Correlation of Ultrasonic Elastography of the Lens With Refractive Error and Biometric Parameters in Non-presbyopic and Presbyopic Patients

Correlation of Ultrasonic Elastography of the Lens With Refractive Error and Biometric Parameters in Non-presbyopic and Presbyopic Patients | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Correlation of Ultrasonic Elastography of the Lens With Refractive Error and Biometric Parameters in Non-presbyopic and Presbyopic Patients Alaa Hussein Qader, Norafida Binti Bahari, Ezamin Bin Abdul Rahim, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7933992/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Presbyopia is the loss of near vision that occurs with ageing due to changes in the lens elasticity and muscle function within the eye. However, the influence of biometric properties and the occurrence of presbyopia are not fully understood. Objective This study investigates the correlation between biometric properties and lens elasticity in individuals with non-presbyopia and presbyopia across various age groups. Methods The study was conducted at the ophthalmology and radiology departments of a large teaching hospital in Selangor, Malaysia. Using a cross-sectional approach, 84 subjects were recruited, with 44 presbyopic and 40 non-presbyopic subjects. The subjects were screened for biometric properties and lens elasticity. Participant eligibility was determined through various tests, including the assessment of refractive errors and visual acuity. Lens thickness and axial length were measured after the best eye was chosen for testing. The eyes were then scanned utilising ultrasound elastography with shear wave technology. Data were analysed using descriptive statistics and Pearson correlation tests. Results Biometric parameters such as amplitude of accommodation (p < 0.001), degree of presbyopia (p < 0.001), lens elasticity (p < 0.001) and lens intensity (p = 0.002) were significantly different between the presbyopic and non-presbyopic subjects. The amplitude of accommodation reduced significantly (p < 0.001) with age, while the degree of presbyopia increased with age compared to younger age subjects (p < 0.001). The mean lens thickness (p = 0.005), elastic degree (p < 0.001), and lens intensity (p < 0.001) increased significantly with advancing age. The elasticity degree was significantly higher in the presbyopia group compared to the non-presbyopia group (13.21 ± 2.09 kPa vs. 6.98 ± 1.73 kPa; p < 0.001). Lens accommodation correlated inversely with lens elasticity degree, whereas the degree of presbyopia correlated positively with lens elasticity degree. Conclusion Biometric properties are promising and reliable indicators in determining lens elasticity and its association with presbyopia. A diagnostic prospective cohort study may be considered in future research to confirm this finding. Such information may assist in developing innovative and cost-effective markers for the early prevention and management of presbyopia. Axial length lens thickness presbyopia ultrasound elastography refractive error Introduction Presbyopia is an age-related near vision impairment, which results from the gradual decrease in accommodation with progressive ageing, leading to multiple effects on quality of vision and quality of life (Kam et al., 2022 ). Presbyopia stands as a significant visual impairment and public health concern affecting the ageing population worldwide. In Malaysia, presbyopia remains a significant concern as the country is experiencing demographic shifts towards an increasingly elderly populace (Ithnin et al., 2023 ). Effective management of presbyopia requires a multidisciplinary approach, encompassing comprehensive ocular assessments, innovative treatment modalities, and public health initiatives aimed at raising awareness and promoting vision care (Majithia et al., 2020 ). Several factors influence the onset and severity of presbyopia, thus further complicating its management (Majithia et al., 2022). Refractive errors such as myopia, hyperopia, and astigmatism can exacerbate presbyopia symptoms, necessitating tailored corrective measures (Berdahl et al., 2020 ). Additionally, the amplitude of accommodation, which declines with age, varies among individuals and affects their ability to focus on near objects (Kubota et al., 2020 ). Assessing the degree of presbyopia and understanding variations in ocular parameters such as axial length and lens thickness are essential in determining appropriate treatment modalities and optimising visual outcomes (McDonald et al., 2022 ). However, these factors may vary across individuals, especially based on their age and their visual acuity, which warrant further investigation (Ithnin et al., 2023 ). Lens elasticity plays an important role in the development and progression of presbyopia. As individuals age, the crystalline lens undergoes structural and biomechanical changes, resulting in reduced flexibility and diminished accommodative ability (Katz et al., 2021 ). These alterations interfere with the eye's ability to adjust focus from distant to near objects, developing as the first symptom of presbyopia (Zhu et al., 2022 ). Research indicates that age-related modifications in the composition and organisation of lens fibres contribute to the loss of accommodation, highlighting the significance of lens biometric properties in understanding the pathophysiology of presbyopia (Berdahl et al., 2020 ). While research on presbyopia and its association with lens elasticity is well-covered (Khadka et al., 2022 ; Zhu et al., 2022 ), there remains a notable gap in understanding the specific biometric properties that influence lens elasticity. Existing studies have primarily focused on age-related changes in lens biomechanics and their impact on presbyopia development (Katz et al., 2021 ), whereas a comprehensive assessment of biometric parameters and their association with lens elasticity is understudied. Elucidating these ocular factors (accommodation, presbyopia, ageing, refractive error, lens thickness, and lens volume), particularly the role of lens elasticity, is crucial for comprehending the characteristics of presbyopia across different biometric properties. This knowledge is essential for developing more effective management strategies. Furthermore, subjective refraction and dynamic retinoscopy are commonly employed in clinical practice to evaluate presbyopia, but the validity and reliability of these methods in quantifying lens intensity remain uncertain (León et al., 2024 ). A revolutionary sonographic method, ultrasonic elastography, uses an additional non-invasive strategy for determining tissue elasticity by static pressure. Currently, two distinct ultrasonic elastography approaches are accessible. In strain-elastography, tissues are compressed along a longitudinal axis, while shear-wave elastography uses transducers to produce shear waves that are then used to probe the tissue (Oğurel & Burulday, 2020 ). The basis of ultrasound-based elastography is by supplying an external load to the tissue and monitoring its distortion at various depths (Chen et al., 2018 ). Unlike strain, shear waves use dynamic stress to create waves in perpendicular or parallel planes. Quantitative and qualitative estimations of tissue flexibility can be obtained by measuring shear-wave velocity (Sigrist et al., 2017 ; Zemanova, 2019). Ultrasound elastography offers a promising alternative for assessing tissue stiffness and elasticity in the crystalline lens (Bontzos et al., 2021 ), yet its utility in validating lens intensity measurements for presbyopia diagnosis and management has not been fully explored. Ultrasound elastography offers an opportunity to validate lens intensity measurements, which are critical in refining diagnostic protocols and optimising treatment strategies (Zemanova, 2019). Overall, biometric assessments of the lens are significant factors that should be considered during diagnosing and treating refractive problems (Kaiti et al., 2021 ; Goulet-Pelletier et al., 2020). However, there is a data paucity regarding the relationship between biometric parameters and refractive error, especially among non-presbyopic and presbyopic subjects. Previous studies have either focused on specific age groups, such as geriatric patients/elderly subjects or the younger population, whereas research encompassing non-presbyopic and presbyopic individuals is limited. The objective of this study is to investigate the correlation between biometric properties and lens elasticity in individuals with non-presbyopia and presbyopia across various age groups. Methods Study design This is observational diagnostic research, representing an initiative for innovative approaches to the delivery of medical care. A cross-sectional study was conducted at the ophthalmology and radiology departments of Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia (UPM) in Serdang, Selangor, Malaysia. The study commenced in April 2021, and the target population comprised individuals aged 19 to 65 visiting the ophthalmology clinic. Study population, sample size and sampling method The study population consisted of patients visiting the ophthalmology department, along with diverse participants, including hospital staff members and volunteer students from UPM. Subjects aged 19 to 65 years old were purposively selected for a comprehensive representation of the targeted demographics. Within this age spectrum, individuals between 41 and 60 were specifically included to account for the onset of presbyopia, a vision-related condition characterised by age-related changes in near vision. Meanwhile, the non-presbyopic group comprised individuals aged 19 to 40, as this age group has a low risk of presbyopia and is rarely affected by the condition. Inclusion and exclusion criteria The inclusion criteria entailed participants visiting HPUPM and providing informed and written consent to participate in this study. Individuals must be between 19 to 65 years old and with the best possible corrected visual acuity of 6/9. A single eye with the clearest vision is to be selected while identifying the best visual acuity monocularly. The exclusion criteria entailed those presented with corrective eye surgery for any refractive defect (‘Lasik’, ‘Laser’, ‘PRK’), patients with amblyopia, any of previous eye surgery, previous trauma to the lens, or thyroid eye disease (exophthalmos), currently on medication that contributes to an increase in fluid retention within the body (water retention), cataract surgery patients with an intraocular lens (IOL), and those diagnosed with cataracts of a grade higher than one or having amblyopia. Diabetic patients and those with macula oedema, keratoconus and other corneal diseases that affect the axis of the eye, advanced stages of glaucoma, and total optic-nerve cupping with a diminished field of vision were excluded. The required sample size was computed based on the primary research objective, which is to determine the correlation between the variables.Top of FormBottom of Form Therefore, correlation and regression tests were selected in G-Power, and utilising the bivariate normal model. The assumed parameters included a study power of 80%, precision level of 5%, correlation ρ H1 of 0.3 and Correlation ρ H0 of 0.0, yielding a total sample of 84. Assessment of refractive error and biometric parameters Multiple eye examinations were performed on the patient’s eyes by a trained assessor. The HUVITS ® auto-refractometer was used to measure all the biometric parameters employed to determine the presence or absence of refractive errors. Visual acuity assessment was performed as described in a previous study (Lee et al., 2010) by using a computerised display screen, and the trial case's lens corrected any vision abnormalities. The results were rated as 6/6, 6/9, 6/12, 6/18, 6/24, 6/36, and 6/60. In cases where the subject had vision issues, the visual acuity was determined by adding lens degrees to the frame. Both assisted and unaided visual acuity readings were reported for each individual. Presbyopia examination and accommodation assessment were performed as described in previous studies (Lee et al., 2010; Chrzanowski, 2020). For further measurements, just one eye with the best vision was chosen. After selecting the clearest eye, the IOL master performed the measurements on the axial length and thickness. For the axial length and lens thickness assessment, the IOL master's achievement was used as the standard, whereby the names and birthdates of the subjects were entered into the device system before the actual check. Data was recorded using assessment sheets, and additional assessment was conducted in radiology employing Canon (Aplio i800) instruments to quantify lens elasticity (Glasser, 2006; Lee et al., 2010; Chrzanowski, 2020). Meanwhile, volume and elasticity measurements were performed using Canon ultrasonography. The data file was stored in the ultrasound machine, and images were downloaded to an external pen drive. Image analysis was performed using the software ImageJ 1.53t, which is able to determine the intensity degree of the lens in both the grayscale and the elastography images (Chrzanowski, 2020). The axial length (AXL) and lens thickness (LT) are measured by the noncontact approach with the use of a technique called ‘PCI’, using information obtained from the retinal pigment epithelium's reflected interference signal (Gaballa et al., 2017). The ZIESS-700 (“Carl-Zeiss Meditec AG”) utilised in this research is built on the concept of ‘SS-OCT’, and it allows observation of the entire eyeball longitudinal plane (Jeon et al., 2020). Presbyopia examination Presbyopia examination was performed by requesting the subject to keep both eyes open while holding the chart at a close working distance of roughly 30 centimetres. The subject was then asked to see if they could read line N8 from the reading chart. If the subject was incapable of reading, a convex lens was added to the frame, and the subject was asked again about their ability to read the line. The degree of presbyopia is equivalent to the lens power that was added (McDonald et al., 2022). A person with mild presbyopia would fall into the category requiring an addition power of up to +1.25D, while moderate presbyopia would require an addition power between more than +1.25D and +2.0D. On the other hand, an advanced presbyopia would necessitate an addition power greater than +2.0D. Age correlates with the amount of prescribed lens power applied; the age range is between 40 to 45 is +1.00, 45 to 60, 50 is +1.50, 50 to 55 is +2.00, 55 to 60 is +2.50, and over 60 is +3.00 or higher (Toit, 2006). Ethical Approval This study was reviewed by the Ethics Committee for Research Involving Human Subjects at the Universiti Putra Malaysia, and approval was granted with the reference number JKEUPM-2022-052. In addition, all the ethical principles for medical research involving human participants, as stipulated in the Declaration of Helsinki, were followed. Image and Data Analysis All data analyses were performed using IBM SPSS, version 26. The data were initially assessed for normality based on the level of skewness and kurtosis. Since all the continuous data were normally distributed, means and standard deviations were computed as measures of central tendency to summarise the dataset. Descriptive analyses were further used to summarise the demographic characteristics of the presbyopic and non-presbyopic subjects. Depending on the type of data, Pearson chi-square and independent t-tests were used to compare the demographic profile and biometric parameters between the two groups, with a p-value set at 0.05. Correlation between either age or lens elasticity and biometric parameters was conducted using Pearson and Spearman correlation coefficients, thus presenting the degree, direction and strength of the association between the variables. The intensity degree of the lens in both the grayscale and the elastography images, as well as the position of the ROI, was determined using the software ImageJ 1.53t. The final result of the measurement was the mean of the histogram degree, which is identical to the intensity degree. As for quantitative data, Results Descriptive characteristics, age distribution and visual acuity A total of 84 participants were recruited in this study, comprising 40 non-presbyopic and 44 presbyopic subjects. Table 1 provides an overview of the subjects’ age distribution. Overall, most of the subjects were aged 41 – 50 (36.9%) and 31 – 40 (35.7%) years old. None of the younger subjects was presbyopic, as 77% and 23% of presbyopic subjects were in the 40-50 and 51-60 age groups, respectively (p <0.001). Seventy-eight of the examined eyes exhibited a visual acuity of 6/6, indicating optimal vision. Within this subset, 34 cases demonstrated normal vision without any discernible refractive errors. The remaining 44 cases required optical aids, specifically corrective lenses, to attain and maintain a visual acuity of 6/6. Further scrutiny identified an additional five cases with a visual acuity of 6/9, which were corrected using supplementary lenses. Only one case within the overall cohort exhibited a visual acuity of 6/12. The overall distribution revealed no significant difference in visual acuity between non-presbyopic and presbyopic subjects (p = 0.59). Table 1: Study characteristics between non-presbyopic and presbyopic patients Frequency (percentage) χ 2 t-test p-value All Non-Presbyopic Presbyopic Age range 19-30 13 (15.5) 13 (32) 0 73.18 <0.001* 31-39 30 (35.7) 27(67) 0 40-50 31 (36.9) 0 34 (77) 51-60 10 (11.9) 0 10(23) Visual acuity 6/12 1 (1.2) 0 1(100.0) 1.06 0.588 6/9 5 (6.0) 2(40.0) 3 (60.0) 6/6 78 (92.9) 38(48.7) 40(51.3) Normal vision 34 (43.6) Optical aided 44 (56.4) Comparisons of Ultrasound Elastography measurements between non-presbyopic and presbyopic subjects Although refraction error was slightly lower in the non-presbyopic group (42%; n = 21) relative to the presbyopic group (58%, n = 29), the difference was not statistically significant (p = 0.211). (Table 2). Remarkably, a conspicuous preponderance of myopia was discerned, constituting a substantial 84% of the entirety of documented refractive errors within the investigated cohort. Presbyopic subjects (2.73±0.88 D) recorded significantly lower AA compared to the non-presbyopic group (2.73±0.88 D) (p <0.001). The AA in the presbyopic subjects was even lower than the normal range (4D – 8D). A high proportion of the subjects (47.6%, n = 40) had insufficient AA, 35.7% ( n = 30) had a normal AA, and 16.7% (n = 14) had excess AA. All the participants with insufficient AA were presbyopia subjects, while those with excess AA were all non-presbyopic subjects. The proportion of those with normal AA was higher among non-presbyopic (86.7%, n =26) compared to presbyopia subjects (13.3%, n = 4) (p<0.001) The average degree of presbyopia was 0.83±0.87 SD, and the value (mean difference (SD) = -1.58 (0.03), p <0.001) was significantly different between the two groups. Subjects with presbyopia displayed a markedly higher elasticity mean of 13.21 ± 2.09 kPa, surpassing both the overall mean and the elasticity observed in the non-presbyopic group. Meanwhile, individuals without presbyopia exhibited a significantly lower lens intensity (26.35 ± 2.98 AU, p = 0.002) compared to the presbyopic subjects (28.34 ± 2.76 AU). Ultrasound elastography data from the non-presbyopic cohort demonstrated a significantly lower mean elasticity value (6.98 kPa) relative to the presbyopic subgroup (13.21 kPa). In contrast, axial length, lens thickness, and lens volume were not significantly different (p>0.05) between the two groups. These results underscore the subtle nature of the variation in these biometric parameters between the two groups, suggesting that presbyopia may not affect these metrics. Table 2: Ultrasound Elastography measurements between non-presbyopic and presbyopic patients Frequency (percentage) χ 2 MD (SE) t-test p-value All Non-Prebyopic Presbyopic Refraction error Yes 50 (40.5) 21(42.0) 29(58.0) 1.56 0.211 No 34 (59.5) 19(55.9) 15(44.1) Amplitude of accommodation Mean ± SD 5.25±3.16 8.03±2.33 2.73±0.88 5.3 (0.02) 13.54 <0.001* Insufficiency 40 (47.6) 0 40 (100.0) 70.10 <0.001* Normal 30(35.7) 26(86.7) 4 (13.3) Excess 14(16.7) 14 (100.0) 0 Degree of presbyopia Mean ± SD 0.83±0.87 0 1.58±0.50 -1.58 (0.03) -20.86 <0.001* Mild (<+1.25D) 25(60.7) 0 11(21.6) 49.41 +2.0D) 13(16.7) 0 14(100.0) Axial length (mm) 23.77±1.01 23.75±0.88 23.79±1.12 -0.03 (0.22) -0.146 0.884 Lens thickness (mm) 3.96±0.31 3.89±0.27 4.02±0.33 -0.13 (0.07) -1.972 0.052 Lens volume (cm 3 ) 0.10±0.01 0.10±0.02 0.10±0.0 0.003 (0.002) 1.049 0.297 Elasticity degree (kPa) 10.24±3.67 6.98±1.73 13.21±2.09 -6.23 (0.42) -14.79 <0.001* Lens intensity 27.39±3.02 26.35±2.98 28.34±2.76 -1.99 (0.63) -3.181 0.002* Elasticity degree (kPa) 10.24±3.67 6.98±1.73 13.21±2.09 -6.23 (0.42) -14.79 <0.001* MD = mean difference, SE = standard error Association between age and biometric parameters No difference was observed in the visual acuity and refractive error between age groups. However, the mean AA reduced significantly as age increased (p<0.001). After 40 years old, a significant proportion of subjects had insufficient AA. Likewise, the mean degree of presbyopia increased significantly with age (p <0.001). Among subjects above 50 years old, 64.3% had an advanced degree of presbyopia compared to the younger age groups (p <0.001). Elasticity degree and lens thickness increased significantly with age (p = 0.005), and also differed significantly across age groups. Nevertheless, despite axial length and lens volume increasing significantly with age, both parameters demonstrated no significant difference across age groups. Table 3: Biometric parameters across various age groups Variables Age (years old) χ 2 F p-value 19-30 31-39 40-50 51-60 Visual acuity 6/12 0 0 0 1(100.0) 9.989 0.125 6/9 0 3(60.0) 1(20.0) 1(20.0) 6/6 13(16.7) 27(34.6) 30(38.5) 8(10.3) Refraction Error Yes 8(16.0) 15(30.0) 20(40.0) 7(14.0) 1.928 0.588 No 5(14.7) 15(44.1) 11(32.4) 3(8.8) Amplitude of accommodation Mean ± SD 9.69±2.45 6.88±2.00 2.82±0.77 2.13±0.92 76.90 <0.001* Insufficiency 0 1(2.5) 30(75.0) 9(22.5) 85.92 <0.001* Normal 5(16.7) 23(76.7) 1(3.3) 1(3.3) Excess 8(57.1) 6(42.9) 0 0 Degree of Presbyopia Mean ± SD 1.42±0.35 2.25±0.31 205.56 <0.001* Mild (<+1.25D) 0 0 11 (25) 0 90.31 +2.0D) 0 0 0 (0) 6(13) Axial length (mm) 23.69±0.74 23.82±1.00 23.63±0.86 24.16±1.62 0.741 0.531 Lens thickness (mm) 3.73±0.25 3.93±0.25 4.01±0.27 4.16±0.47 4.681 0.005* Lens volume (cm 3 ) 0.10±0.00 0.10±0.02 0.10±0.0 0.10±0.00 0.591 0.623 Elasticity degree (kPa) 6.63±1.77 7.47±1.89 12.78±1.66 15.41±1.71 92.26 <0.001* Lens intensity 25.54±2.95 26.56±2.87 28.32±2.47 29.40±3.29 5.656 0.001* Table 4 presents the bivariate correlation between age and biometric parameters. Accommodation displayed a significant, inverse and strong correlation with age (r = -0.89), whereas the degree of presbyopia correlated strongly and positively with age (r = 0.75). Lens thickness had a significant and moderate correlation with age (r = 0.38). Axial length and lens volume depicted no correlation with age. Table 4: Correlation analysis of biometric parameters, presbyopia measurement and age Variables Age (years old) Bivariate correlation (r) p-value Accommodation -0.892 <0.001** Degree of Presbyopia 0.889 <0.001** Axial length 0.035 0.749 Lens thickness 0.380 <0.001** Lens volume -0.007 0.949 **. Correlation is significant at the 0.01 level (2-tailed). Relationship between lens elasticity degree, refractive error, and biometric parameters As shown in Table 5, no relationship was observed between refraction error and lens elasticity degree (p = 0.667), indicating that the lens elasticity degree is unaffected by refraction errors. Meanwhile, lens accommodation depicted a negative and strong correlation with lens elasticity degree (r = -0.85); however, upon adjusting for age, a weak negative correlation was detected (p = -0.27). The degree of presbyopia showed a direct, strong and significant correlation with lens elasticity degree (r = 0.88), and the relationship was moderate (r = 0.54) after being adjusted for age. Lens thickness displayed a weak but significant correlation with lens elasticity degree (p = 0.27), but the relationship was not significant after controlling for age. Detailed description of the linear relationship between the variables is provided in the Supplementary file. Table 7: Bivariate and partial correlation analysis of presbyopia measurement, lens elasticity degree and biometric parameters Variables Lens elasticity degree Bivariate correlation (r) p-value Partial correlation (r partial ) p-value Refraction error 0.072 0.667 0.052 0.456 Accommodation -0.815 <0.001* -0.274 0.012* Degree of Presbyopia 0.880 <0.001* 0.540 <0.001* Axial length 0.006 0.959 -0.044 0.693 Lens thickness 0.268 0.014* -0.101 0.363 Discussion The main aim of this study is to investigate the biometric properties and lens elasticity in individuals with non-presbyopia and presbyopia across various age groups. Understanding the biometric properties and lens elasticity in individuals with and without presbyopia holds significant implications in the field of optometry, ophthalmology, and ageing research. In this study, subjects with presbyopia had a significantly lower amplitude of accommodation compared to non-presbyopic subjects. Presbyopia is a common age-related condition characterised by a progressive decline in the amplitude of accommodation (Kam et al., 2022). Such individuals experience reduced flexibility and efficiency in accommodating to near objects. One primary mechanism in presbyopia is the changes in the composition and properties of the crystalline lens (Kubota et al., 2020). With age, the crystalline lens becomes less elastic and more rigid, impairing its ability to change shape effectively in response to ciliary muscle contraction. This loss of lens flexibility diminishes the eye's ability to adjust its focus for near vision tasks, contributing to presbyopia (Khadka et al., 2022). Another contributing factor is the gradual weakening of the ciliary muscles responsible for controlling lens shape (Cabeza-Gil et al., 2021). With advancing age, the ciliary muscles weaken, leading to diminished contractility and reduced accommodation amplitude (Ithnin et al., 2023; Zhang et al., 2022). Presbyopic subjects also demonstrated a higher lens elasticity degree compared to non-presbyopic subjects. This finding suggests the association between lens elasticity and onset of presbyopia might be shaped by other mechanisms, leading to a paradoxical increase in elasticity among presbyopic individuals. The lens of presbyopic individuals may undergo compensatory changes in response to the loss of accommodative ability (Cacho et al., 2002). As the crystalline lens becomes less elastic with age, adaptations within the lens capsule or alterations in the surrounding structures, such as the ciliary muscle and zonular fibres, may attempt to maintain some degree of flexibility and focusing ability (Zhang et al., 2018). These conditions may lead to a perceived increase in lens elasticity among presbyopic individuals, despite the underlying age-related changes (Zhang et al., 2022). The static analysis revealed a strong correlation between lens elasticity and the presbyopic cohort, but such a relationship was absent in the non-presbyopic group (Gennisson et al., 2013). This empirical observation lends support to the validation of ultrasound elastography outputs. Within the non-presbyopic cohort, it is posited that accommodation operates optimally and conventionally (Zhang et al., 2022). This comparison is consistent with established physiological parameters, which may exhibit inherent inter-individual variations while consistently maintaining an overarching normal range. Notably, these parameters remain unaffected by the chronological progression of age (Manns et al., 2022). An additional corroborating factor covering the aforementioned theory is the negative correlation between the degree of elasticity and accommodation. As the elasticity of the lens decreases, denoted by higher kPa values and indicative of increased rigidity, a corresponding reduction in accommodation ensues (Detorakis et al., 2013). This inverse relationship underscores the pivotal role of lens biomechanics in the accommodation process. We found significant correlations between lens elasticity and key variables such as age, accommodation, and the presence of presbyopia. This finding suggests a discernible relationship between these variables, contributing valuable insights into the interplay of these parameters within the ocular system. The consistency between our study and previous research lends credibility to the identified relationships and contributes to the growing body of knowledge in the field (Chen et al., 2021; Fekadu et al., 2021; Liu et al., 2023). In this study, higher accommodation correlated with lower elasticity, whereas a higher degree of presbyopia and lens thickness was associated with higher lens elasticity. No significant correlation was detected between refractive error and the lens elasticity degree across age groups. The insignificant results may stem from various ways in which refractive errors are manifested, each affecting vision in distinct manners (Bhardwaj & Rajeshbhai, 2013). Furthermore, this finding sheds more light on our preceding observation, where the correlation between lens elasticity degree and axial length, as well as lens thickness, was significant. Collectively, these findings suggest that lens elasticity is moderately influenced by biometric properties. The proportion of refractive error was higher among presbyopic subjects, aligning with prior research outcomes affirming the pervasive nature of myopia in East Asian populations. For instance, prevalence estimates indicate that over 50% of cases of refractive errors (Majithia et al., 2020). This high prevalence has been consistently observed in countries such as Korea, Japan, Singapore, and China, substantiating the widespread nature of myopia in this region (Kaiti et al., 2020). These findings suggest that the degree of lens elasticity across various age groups is contingent upon the physiological ageing processes occurring within the eye, rather than being attributable to refractive anomalies. Therefore, while the elasticity of the lens can exert an impact on vision, such effects may not be directly associated with refractive errors in the eye. The observed correlations suggest a complex interplay between lens elasticity, age-related changes, and the manifestation of refractive conditions. The inverse association between accommodation and lens elasticity illustrates the dynamic lens thickness for focal ..s among individuals, with some exhibiting higher levels of elasticity even in the presence of advanced presbyopia. This variability might be influenced by genetic factors, environmental influences, or other unknown variables. Lens power is determined by curvature and refractive index. The optical power of the human eye lens is intricately governed by its curvature and refractive index, important factors orchestrating the lens's ability to focus incident light onto the retina (Bassnett, 2021). Limitations and recommendations This study is subject to important limitations. All the research modalities and instruments are exclusive to a single hospital, leading to the use of identical devices for outpatient assessments. There were delays given the necessity to conduct assessments during periods of reduced patient activity owing to time constraints. A large sample size was not recruited since the study was restricted to the Ophthalmology and Radiology departments. These distinct yet interconnected sections, situated within proximity, necessitate completion for each participant to finalise the dataset and facilitate report writing. Challenges were faced during certain assessments as the imaging equipment was concurrently utilised by multiple ophthalmologists and patients, leading to extended wait times. In response, these patients opted to defer their participation and agreed to return on the subsequent day. Given the voluntary nature of the data collection, it was incumbent upon the patients to revisit the respective department to complete the data collection or testing process. Despite being beyond the researcher’s control, these issues do not significantly influence the overall outcome. Nonetheless, this limitation reflects the need to accrue a more extensive dataset from the patient cohort. The lack of comparable research also limits the opportunity for the external validation of our findings. Consequently, this limitation affected the corroboration of the present data with existing literature. Nevertheless, this study serves as a foundational platform for subsequent investigations in the field. The diverse demographic backgrounds of patients, encompassing various ethnicities and age groups, added complexity to the process. Although this diversity did not compromise the accuracy of data collection, it did contribute to an extended duration required for patient interaction and engagement. For future research, a broader age range is deemed essential to enhance the inclusivity of diverse age groups. A distinct population of cataract patients also warrants consideration to ascertain the elasticity degree and its correlation with cataract grade. Utilising ultrasound elastography images as a reference, there exists an opportunity to establish a novel categorisation and classification of presbyopia grounded in the elasticity degree and its intensity, thus contributing to a refined understanding of this condition. Given the reliance on ultrasound elastography for assessing lens elasticity, ensuring consistency in output values across multiple cases is paramount. Quality assurance measures, including standardised protocols, regular calibration, and ongoing training for operators, should be implemented to maintain precision and reliability in measurements obtained from ultrasound elastography machines. Given the significant differences observed in age distribution, amplitude of accommodation, and degree of presbyopia between presbyopic and non-presbyopic subjects, it is crucial to implement age-specific screening protocols for early detection and intervention. Regular eye examinations, particularly for individuals approaching middle age and beyond, can aid in identifying presbyopia and initiating appropriate management strategies promptly. Incorporating biometric assessments, including lens elasticity measurements, into routine eye examinations can provide valuable insights into the progression of presbyopia and aid in personalised treatment planning. Clinicians should consider integrating techniques such as lenticular elastography ultrasound to accurately evaluate lens elasticity and monitor changes over time. Based on the observed higher elasticity degree in the presbyopia group compared to the non-presbyopia group, there is a need for further research to explore the underlying mechanisms driving changes in lens elasticity with age. Investigating factors influencing lens elasticity, such as genetic predisposition, lifestyle factors, and environmental influences, can inform the development of targeted interventions aimed at preserving or restoring the function of the human lens. Conclusion This study revealed significant differences in several biometric parameters between presbyopic and non-presbyopic subjects, highlighting the influence of age-related changes on ocular characteristics. With advancing age, the amplitude of accommodation reduced progressively while the degree of presbyopia increased. Additionally, lens thickness, elasticity degree, and lens intensity were found to significantly increase with age, indicating age-related changes in the biomechanical properties of the lens. Presbyopic individuals exhibited higher elasticity degrees, with the elasticity degree increasing significantly with age. Correlation analyses further revealed strong associations between lens elasticity and factors such as lens accommodation and the degree of presbyopia. These findings underscore the potential utility of biometric properties as reliable indicators of lens elasticity, particularly in the context of presbyopia. Understanding the relationship between these parameters could aid in the development of innovative and cost-effective markers for early detection and management of presbyopia. Declarations Conflict of Interest None Funds None Author Contribution Conception and design: AHQ, NBB, RBMSAnalysis and interpretation of the data: EBA, MBMZ, AHQDrafting of the article: AHQCritical revision of the article for important intellectual content: AHQ, NBB, RBMS, EBAFinal approval of the article: AHQ, AHQ, NBB, RBMS, EBA, MBMZProvision of study materials or patients: AHQ, NBB, RBMSStatistical expertise: AHQ, NBBAdministrative, technical, or logistic support: NBBCollection and assembly of data: AHQ Data Availability Data will be made available upon request from the authors References Berdahl, J., Bala, C., Dhariwal, M., Lemp-Hull, J., Thakker, D., & Jawla, S. (2020). Patient and economic burden of presbyopia: a systematic literature review. Clinical Ophthalmology , 3439–3450. Bhardwaj, V., & Rajeshbhai, G. P. (2013). Axial length, anterior chamber depth-a study in different age groups and refractive errors. Journal of clinical and diagnostic research: JCDR, 7(10), 2211. Bassnett, S. (2021). Zinn's zonule. Progress in retinal and eye research , 82 , 100902. Bontzos, G., Douglas, V. P., Douglas, K. A., Kapsala, Z., Drakonaki, E. E., & Detorakis, E. T. (2021). Ultrasound elastography in ocular and periocular tissues: A review. Current Medical Imaging , 17 (9), 1041–1053. Chen, P. Y., Shih, C. C., Lin, W. C., Ma, T., Zhou, Q., Shung, K. K., & Huang, C. C. (2018). High-resolution shear wave imaging of the human cornea using a dual-element transducer. Sensors , 18 (12), 4244. Chrzanowski KT. Measurement of eyepiece diopter of direct view imagers. Opto-Electronics Rev . 2020;28. http://dx.doi.org/10.24425/opelre.2020.135373 Cabeza-Gil, I., Grasa, J., & Calvo, B. (2021). A numerical investigation of changes in lens shape during accommodation. Scientific Reports , 11 (1), 9639. Cacho, P., García, A., Lara, F., & Seguí, M. (2002). Diagnostic signs of accommodative insufficiency. Optometry and Vision Science , 79 (9), 614–620. Chen, L. J., Chang, Y. J., Shieh, C. F., Yu, J. H., & Yang, M. C. (2021). Relationship between practices of eye protection against solar ultraviolet radiation and cataract in a rural area. PloS one , 16 (7), e0255136. Du Toit, R. (2006). How to prescribe spectacles for presbyopia. Community Eye Health , 19 (57), 12. Fekadu, S. A., Seid, M. A., Akalu, Y., Gela, Y. Y., Diress, M., Getnet, M., … Belsti, Y. (2022). Factors associated with diabetic retinopathy screening and regular eye checkup practice among diabetic patients attending Felege Hiwot Specialized Hospital. International Journal of Ophthalmology , 15 (11), 1829. Gennisson, J. L., Deffieux, T., Fink, M., & Tanter, M. (2013). Ultrasound elastography: principles and techniques. Diagnostic and interventional imaging , 94 (5), 487–495. Glasser, A. (2006). Accommodation: mechanism and measurement. Ophthalmol Clin North Am , 19 (1), 1–12. Ithnin, M. H., Othman, S. F., Abd Aziz, N. A., & Adnan, M. A. H. M. (2023). The Status Of Myopia Refractive Error From 2018 Until 2021 Among Aged 30 To 35 Years Old In A Private Optometry Practice, Dungun, Malaysia: Retrospective Data. International Journal Of Allied Health Sciences , 7 (5). Kaiti, R., Shyangbo, R., Sharma, I. P., & Dahal, M. (2021). Review on current concepts of myopia and its control strategies. International Journal of Ophthalmology , 14 (4), 606. Kam, K. W., Pang, C. P., & Yam, J. C. (2022). Refractive Errors, Myopia, and Presbyopia. Ophthalmic Epidemiology , 87–112. Katz, J. A., Karpecki, P. M., Dorca, A., Chiva-Razavi, S., Floyd, H., Barnes, E., … Donnenfeld, E. (2021). Presbyopia–A review of current treatment options and emerging therapies. Clinical Ophthalmology , 2167–2178. Khadka, N. K., Timsina, R., & Mainali, L. (2022). An AFM Approach Applied in a Study of α-Crystallin Membrane Association: New Insights into Lens Hardening and Presbyopia Development. Membranes , 12 (5), 522. Kubota, M., Kubota, S., Kobashi, H., Ayaki, M., Negishi, K., & Tsubota, K. (2020). Difference in pupillary diameter as an important factor for evaluating amplitude of accommodation: a prospective observational study. Journal of Clinical Medicine , 9 (8), 2678. Lee, A. C., Qazi, M. A., & Pepose, J. S. (2008). Biometry and intraocular lens power calculation. Current opinion in ophthalmology , 19 (1), 13–17. León, A., Rosenfield, M., Medrano, S. M., Durán, S. C., & Pinzón, C. V. (2024). Objective and subjective assessment of accommodative insufficiency. Optometry and Vision Science , 101 (1), 44–54. Liu, M. X., Li, D. L., Yin, Z. J., Li, Y. Z., Zheng, Y. J., Qin, Y., … Pan, C. W. (2023). Smoking, alcohol consumption and corneal biomechanical parameters among Chinese university students. Eye , 37 (13), 2723–2729. Majithia, S., Wong, K. H., Chee, M. L., Soh, Z. D., Thakur, S., Fang, X. L., … Cheng, C. Y. (2020). Normative patterns and factors associated with presbyopia progression in a multiethnic Asian population: the Singapore Epidemiology of Eye Diseases Study. British Journal of Ophthalmology , 104 (11), 1591–1595. Manns, F., Durkee, H. A., Chang, Y. C., Mesquita, G. M., Williams, S., Cabot, F., … Parel, J. M. A. (2020). Effect of inter-individual accondas in ocular parameters on optical and mechanical accommodation efficiency. Investigative Ophthalmology & Visual Science , 61 (7), 4637–4637. McDonald, M. B., Barnett, M., Gaddie, I. B., Karpecki, P., Mah, F., Nichols, K. K., & Trattler, W. B. (2022). Classification of presbyopia by severity. Ophthalmology and therapy , 11 (1), 1–11. Oğurel, T., & Burulday, V. (2020). Strain and Shear Wave Elastography in Diagnosis of Retrobulbar Neuritis. Journal of neuro-ophthalmology: the official journal of the North American Neuro-Ophthalmology Society , 40 (2), 169–173. Sigrist, R. M. S., Liau, J., Kaffas, A. E., Chammas, M. C., & Willmann, J. K. (2017). Ultrasound elastography: review of techniques and clinical applications. Theranostics 7: 1303–1329. Zemanová, M. (2019). Shear wave elastography in ophthalmic diagnosis. Journal Français d'Ophtalmologie , 42 (1), 73–80. Song, J. S., Hyon, J. Y., & Jeon, H. S. (2020). Comparison of ocular biometry and refractive outcomes using IOL master 500, IOL master 700, and Lenstar LS900. Korean journal of ophthalmology: KJO , 34 (2), 126–132. Zhang, H., Singh, M., Zvietcovich, F., Larin, K. V., & Aglyamov, S. R. (2022). Age-related viscoelasticity changes in rabbit lens measured by optical coherence elastography. Optical Elastography and Tissue Biomechanics VIV , 11962 (24–30). Zhang, X., Wang, Q., Lyu, Z., Gao, X., Zhang, P., Lin, H., … Chen, X. (2018). Noninvasive assessment of age-related stiffness of crystalline lenses in a rabbit model using ultrasound elastography. Biomedical Engineering Online , 17 (1), 1–11. Zhu, Y., Zhong, Y., & Fu, Y. (2022). The effects of premium intraocular lenses on presbyopia treatments. Advances in Ophthalmology Practice and Research , 2 (1), 100042. Additional Declarations No competing interests reported. Supplementary Files SupplementaryFigure1.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7933992","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":542276845,"identity":"f1774687-fc1e-40c8-8d73-43f5c4258934","order_by":0,"name":"Alaa Hussein Qader","email":"","orcid":"","institution":"Universiti Putra Malaysia","correspondingAuthor":false,"prefix":"","firstName":"Alaa","middleName":"Hussein","lastName":"Qader","suffix":""},{"id":542276846,"identity":"9a99d23c-1313-4c1c-8076-9a17a887737f","order_by":1,"name":"Norafida Binti Bahari","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYDAC5oMNEowNDAkMDIyNDyBCCQS0sCXCtTQbEKklgQGqhYFNgigt/G3MjTd+7rDL4599uK2ad8c2Bn72HAOmm224tUgcY2y27D2TXCxxLrHtNu+Z2wySPW8MmHPxaGG439gmwdvGnNhwhhGope02g8GNHPxa5I8xtkn+batPnA/UUgzSYk9IiwFQizRv2+HEDUAtzGBbJAhoMQT6xVr2zPHEjWcYmyXnnrnNI3HmWcHhnHO4tcgdY3948+2O6sR5Z9gffni747Ycf3vyxsc5ZXi8jwKAEcQDog8wspGgBQr+EKtlFIyCUTAKRgAAAI/oWFKWDCZiAAAAAElFTkSuQmCC","orcid":"","institution":"Universiti Putra Malaysia","correspondingAuthor":true,"prefix":"","firstName":"Norafida","middleName":"Binti","lastName":"Bahari","suffix":""},{"id":542276847,"identity":"2b930fc2-e56e-482b-8a5b-decae8738824","order_by":2,"name":"Ezamin Bin Abdul Rahim","email":"","orcid":"","institution":"Universiti Putra Malaysia","correspondingAuthor":false,"prefix":"","firstName":"Ezamin","middleName":"Bin Abdul","lastName":"Rahim","suffix":""},{"id":542276848,"identity":"353dc470-e38f-4156-8f8a-ecb073957c53","order_by":3,"name":"Rafidah Binti Md Saleh","email":"","orcid":"","institution":"Universiti Putra Malaysia","correspondingAuthor":false,"prefix":"","firstName":"Rafidah","middleName":"Binti Md","lastName":"Sa","suffix":"Md"},{"id":542276849,"identity":"542fc1cd-145f-435d-b7fa-ffaa259327ca","order_by":4,"name":"Muhsonat Binti Mohamad Zain","email":"","orcid":"","institution":"Hospital Pengajar, Universiti Putra Malaysia","correspondingAuthor":false,"prefix":"","firstName":"Muhsonat","middleName":"Binti Mohamad","lastName":"Zain","suffix":""}],"badges":[],"createdAt":"2025-10-23 16:23:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7933992/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7933992/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":95540361,"identity":"d943f4ed-14ee-4c74-a0a1-5710f38f7fbf","added_by":"auto","created_at":"2025-11-10 11:24:03","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72117,"visible":true,"origin":"","legend":"","description":"","filename":"Revisedwithoutchanges.docx","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/f402ce9bd0585a9710d97467.docx"},{"id":95540360,"identity":"21bf38dd-65cf-41dd-8fde-94f948f1e7da","added_by":"auto","created_at":"2025-11-10 11:24:03","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7645,"visible":true,"origin":"","legend":"","description":"","filename":"5f31f2747d054760a771dc0fb84fff60.json","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/9fc23825e38e5fc5bd7e27f3.json"},{"id":95540358,"identity":"96412248-0d87-4cb2-971a-5cb1b9d7c2a3","added_by":"auto","created_at":"2025-11-10 11:24:03","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":148409,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryFigure1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/a8630bc4dc6bbf38edc36961.docx"},{"id":95540357,"identity":"ba782659-f625-46ef-862e-4f4d676e8bc8","added_by":"auto","created_at":"2025-11-10 11:24:02","extension":"xml","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":127738,"visible":true,"origin":"","legend":"","description":"","filename":"5f31f2747d054760a771dc0fb84fff601enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/4b5141d101f6142a154918ce.xml"},{"id":95540362,"identity":"8d07aba6-216f-4944-88a2-521b60447596","added_by":"auto","created_at":"2025-11-10 11:24:04","extension":"xml","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":127541,"visible":true,"origin":"","legend":"","description":"","filename":"5f31f2747d054760a771dc0fb84fff601structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/1e6279bbf9616278d97035d6.xml"},{"id":95654486,"identity":"ee28c340-976f-42b9-a8b8-d6eb5e22f168","added_by":"auto","created_at":"2025-11-11 16:12:09","extension":"html","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":136770,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/66a7574184e1b6ca6fa6724d.html"},{"id":96913599,"identity":"854b8ec2-27d0-4456-90ad-0e408bd0679d","added_by":"auto","created_at":"2025-11-27 14:03:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1149997,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/36dbdb39-97c8-4f5e-82fa-c2ae11b0828f.pdf"},{"id":95540366,"identity":"298bc1f4-e2ef-4d50-8b44-8bc671f32864","added_by":"auto","created_at":"2025-11-10 11:24:05","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":148409,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryFigure1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7933992/v1/1e25786d09f0598948070739.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eCorrelation of Ultrasonic Elastography of the Lens With Refractive Error and Biometric Parameters in Non-presbyopic and Presbyopic Patients\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePresbyopia is an age-related near vision impairment, which results from the gradual decrease in accommodation with progressive ageing, leading to multiple effects on quality of vision and quality of life (Kam et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Presbyopia stands as a significant visual impairment and public health concern affecting the ageing population worldwide. In Malaysia, presbyopia remains a significant concern as the country is experiencing demographic shifts towards an increasingly elderly populace (Ithnin et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Effective management of presbyopia requires a multidisciplinary approach, encompassing comprehensive ocular assessments, innovative treatment modalities, and public health initiatives aimed at raising awareness and promoting vision care (Majithia et al., \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eSeveral factors influence the onset and severity of presbyopia, thus further complicating its management (Majithia et al., 2022). Refractive errors such as myopia, hyperopia, and astigmatism can exacerbate presbyopia symptoms, necessitating tailored corrective measures (Berdahl et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Additionally, the amplitude of accommodation, which declines with age, varies among individuals and affects their ability to focus on near objects (Kubota et al., \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Assessing the degree of presbyopia and understanding variations in ocular parameters such as axial length and lens thickness are essential in determining appropriate treatment modalities and optimising visual outcomes (McDonald et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). However, these factors may vary across individuals, especially based on their age and their visual acuity, which warrant further investigation (Ithnin et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eLens elasticity plays an important role in the development and progression of presbyopia. As individuals age, the crystalline lens undergoes structural and biomechanical changes, resulting in reduced flexibility and diminished accommodative ability (Katz et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). These alterations interfere with the eye's ability to adjust focus from distant to near objects, developing as the first symptom of presbyopia (Zhu et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Research indicates that age-related modifications in the composition and organisation of lens fibres contribute to the loss of accommodation, highlighting the significance of lens biometric properties in understanding the pathophysiology of presbyopia (Berdahl et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWhile research on presbyopia and its association with lens elasticity is well-covered (Khadka et al., \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Zhu et al., \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), there remains a notable gap in understanding the specific biometric properties that influence lens elasticity. Existing studies have primarily focused on age-related changes in lens biomechanics and their impact on presbyopia development (Katz et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), whereas a comprehensive assessment of biometric parameters and their association with lens elasticity is understudied. Elucidating these ocular factors (accommodation, presbyopia, ageing, refractive error, lens thickness, and lens volume), particularly the role of lens elasticity, is crucial for comprehending the characteristics of presbyopia across different biometric properties. This knowledge is essential for developing more effective management strategies.\u003c/p\u003e\u003cp\u003eFurthermore, subjective refraction and dynamic retinoscopy are commonly employed in clinical practice to evaluate presbyopia, but the validity and reliability of these methods in quantifying lens intensity remain uncertain (Le\u0026oacute;n et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). A revolutionary sonographic method, ultrasonic elastography, uses an additional non-invasive strategy for determining tissue elasticity by static pressure. Currently, two distinct ultrasonic elastography approaches are accessible. In strain-elastography, tissues are compressed along a longitudinal axis, while shear-wave elastography uses transducers to produce shear waves that are then used to probe the tissue (Oğurel \u0026amp; Burulday, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). The basis of ultrasound-based elastography is by supplying an external load to the tissue and monitoring its distortion at various depths (Chen et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Unlike strain, shear waves use dynamic stress to create waves in perpendicular or parallel planes. Quantitative and qualitative estimations of tissue flexibility can be obtained by measuring shear-wave velocity (Sigrist et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Zemanova, 2019). Ultrasound elastography offers a promising alternative for assessing tissue stiffness and elasticity in the crystalline lens (Bontzos et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2021\u003c/span\u003e), yet its utility in validating lens intensity measurements for presbyopia diagnosis and management has not been fully explored. Ultrasound elastography offers an opportunity to validate lens intensity measurements, which are critical in refining diagnostic protocols and optimising treatment strategies (Zemanova, 2019).\u003c/p\u003e\u003cp\u003eOverall, biometric assessments of the lens are significant factors that should be considered during diagnosing and treating refractive problems (Kaiti et al., \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Goulet-Pelletier et al., 2020). However, there is a data paucity regarding the relationship between biometric parameters and refractive error, especially among non-presbyopic and presbyopic subjects. Previous studies have either focused on specific age groups, such as geriatric patients/elderly subjects or the younger population, whereas research encompassing non-presbyopic and presbyopic individuals is limited. The objective of this study is to investigate the correlation between biometric properties and lens elasticity in individuals with non-presbyopia and presbyopia across various age groups.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy design\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis is observational diagnostic research, representing an initiative for innovative approaches to the delivery of medical care. A cross-sectional study was conducted at the ophthalmology and radiology departments of Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia (UPM) in Serdang, Selangor, Malaysia. The study commenced in April 2021, and the target population comprised individuals aged 19 to 65 visiting the ophthalmology clinic.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy population, sample size and sampling method\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study population consisted of patients visiting the ophthalmology department, along with diverse participants, including hospital staff members and volunteer students from UPM. Subjects aged 19 to 65 years old were purposively selected for a comprehensive representation of the targeted demographics. Within this age spectrum, individuals between 41 and 60 were specifically included to account for the onset of presbyopia, a vision-related condition characterised by age-related changes in near vision. Meanwhile, the non-presbyopic group comprised individuals aged 19 to 40, as this age group has a low risk of presbyopia and is rarely affected by the condition.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eInclusion and exclusion criteria\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe inclusion criteria entailed participants visiting HPUPM and providing informed and written consent to participate in this study. Individuals must be between 19 to 65 years old and with the best possible corrected visual acuity of 6/9. A single eye with the clearest vision is to be selected while identifying the best visual acuity monocularly. The exclusion criteria entailed those presented with corrective eye surgery for any refractive defect (‘Lasik’, ‘Laser’, ‘PRK’), patients with amblyopia, any of previous eye surgery, previous trauma to the lens, or thyroid eye disease (exophthalmos), currently on medication that contributes to an increase in fluid retention within the body (water retention), cataract surgery patients with an intraocular lens (IOL), and those diagnosed with cataracts of a grade higher than one or having amblyopia. Diabetic patients and those with macula oedema, keratoconus and other corneal diseases that affect the axis of the eye, advanced stages of glaucoma, and total optic-nerve cupping with a diminished field of vision were excluded.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe required sample size was computed based on the primary research objective, which is to determine the correlation between the variables.Top of FormBottom of Form Therefore, correlation and regression tests were selected in G-Power, and utilising the bivariate normal model. The assumed parameters included a study power of 80%, precision level of 5%, correlation ρ H1 of 0.3 and Correlation ρ H0 of 0.0, yielding a total sample of 84.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAssessment of refractive error and biometric parameters\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMultiple eye examinations were performed on the patient’s eyes by a trained assessor. The HUVITS\u003csup\u003e®\u003c/sup\u003e auto-refractometer was used to measure all the biometric parameters employed to determine the presence or absence of refractive errors. Visual acuity assessment was performed as described in a previous study (Lee et al., 2010) by using a computerised display screen, and the trial case's lens corrected any vision abnormalities. The results were rated as 6/6, 6/9, 6/12, 6/18, 6/24, 6/36, and 6/60. In cases where the subject had vision issues, the visual acuity was determined by adding lens degrees to the frame. Both assisted and unaided visual acuity readings were reported for each individual. Presbyopia examination and accommodation assessment were performed as described in previous studies (Lee et al., 2010; Chrzanowski, 2020).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFor further measurements, just one eye with the best vision was chosen. After selecting the clearest eye, the IOL master performed the measurements on the axial length and thickness. For the axial length and lens thickness assessment, the IOL master's achievement was used as the standard, whereby the names and birthdates of the subjects were entered into the device system before the actual check. Data was recorded using assessment sheets, and additional assessment was conducted in radiology employing Canon (Aplio i800) instruments to quantify lens elasticity (Glasser, 2006; Lee et al., 2010; Chrzanowski, 2020). Meanwhile, volume and elasticity measurements were performed using Canon ultrasonography. The data file was stored in the ultrasound machine, and images were downloaded to an external pen drive. Image analysis was performed using the software ImageJ 1.53t, which is able to determine the intensity degree of the lens in both the grayscale and the elastography images (Chrzanowski, 2020).\u003c/p\u003e\n\u003cp\u003eThe axial length (AXL) and lens thickness (LT) are measured by the noncontact approach with the use of a technique called ‘PCI’, using information obtained from the retinal pigment epithelium's reflected interference signal (Gaballa et al., 2017). The ZIESS-700 (“Carl-Zeiss Meditec AG”) utilised in this research is built on the concept of ‘SS-OCT’, and it allows observation of the entire eyeball longitudinal plane (Jeon et al., 2020).\u003c/p\u003e\n\u003ch2\u003e\u003cem\u003ePresbyopia examination\u0026nbsp;\u003c/em\u003e\u003c/h2\u003e\n\u003cp\u003ePresbyopia examination was performed by requesting the subject to keep both eyes open while holding the chart at a close working distance of roughly 30 centimetres. The subject was then asked to see if they could read line N8 from the reading chart. If the subject was incapable of reading, a convex lens was added to the frame, and the subject was asked again about their ability to read the line. The degree of presbyopia is equivalent to the lens power that was added (McDonald et al., 2022). A person with mild presbyopia would fall into the category requiring an addition power of up to +1.25D, while moderate presbyopia would require an addition power between more than +1.25D and +2.0D. On the other hand, an advanced presbyopia would necessitate an addition power greater than +2.0D. Age correlates with the amount of prescribed lens power applied; the age range is between 40 to 45 is +1.00, 45 to 60, 50 is +1.50, 50 to 55 is +2.00, 55 to 60 is +2.50, and over 60 is +3.00 or higher (Toit, 2006).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eEthical Approval\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was reviewed by the Ethics Committee for Research Involving Human Subjects at the Universiti Putra Malaysia, and approval was granted with the reference number JKEUPM-2022-052. In addition, all the ethical principles for medical research involving human participants, as stipulated in the Declaration of Helsinki, were followed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImage and Data Analysis\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data analyses were performed using IBM SPSS, version 26. The data were initially assessed for normality based on the level of skewness and kurtosis. Since all the continuous data were normally distributed, means and standard deviations were computed as measures of central tendency to summarise the dataset. Descriptive analyses were further used to summarise the demographic characteristics of the presbyopic and non-presbyopic subjects. Depending on the type of data, Pearson chi-square and independent t-tests were used to compare the demographic profile and biometric parameters between the two groups, with a p-value set at 0.05. Correlation between either age or lens elasticity and biometric parameters was conducted using Pearson and Spearman correlation coefficients, thus presenting the degree, direction and strength of the association between the variables. The intensity degree of the lens in both the grayscale and the elastography images, as well as the position of the ROI, was determined using the software ImageJ 1.53t. The final result of the measurement was the mean of the histogram degree, which is identical to the intensity degree. As for quantitative data,\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eDescriptive characteristics, age distribution and visual acuity\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 84 participants were recruited in this study, comprising 40 non-presbyopic and 44 presbyopic subjects. Table 1 provides an overview of the subjects\u0026rsquo; age distribution. Overall, most of the subjects were aged 41 \u0026ndash; 50 (36.9%) and 31 \u0026ndash; 40 (35.7%) years old. None of the younger subjects was presbyopic, as 77% and 23% of presbyopic subjects were in the 40-50 and 51-60 age groups, respectively (p \u0026lt;0.001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSeventy-eight of the examined eyes exhibited a visual acuity of 6/6, indicating optimal vision. Within this subset, 34 cases demonstrated normal vision without any discernible refractive errors. The remaining 44 cases required optical aids, specifically corrective lenses, to attain and maintain a visual acuity of 6/6. Further scrutiny identified an additional five cases with a visual acuity of 6/9, which were corrected using supplementary lenses. Only one case within the overall cohort exhibited a visual acuity of 6/12. The overall distribution revealed no significant difference in visual acuity between non-presbyopic and presbyopic subjects (p = 0.59).\u003c/p\u003e\n\u003cp id=\"_Toc164851361\"\u003eTable 1: Study characteristics between non-presbyopic and presbyopic patients\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrequency (percentage)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026chi;\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003et-test\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAll\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNon-Presbyopic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePresbyopic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge range\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19-30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13 (15.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13 (32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e73.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e31-39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30 (35.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27(67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40-50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e31 (36.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e34 (77)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e51-60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10 (11.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10(23)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eVisual acuity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6/12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1 (1.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.06\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.588\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6/9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5 (6.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2(40.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3 (60.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6/6\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e78 (92.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e38(48.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40(51.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNormal vision\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e34 (43.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eOptical aided\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e44 (56.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eComparisons of Ultrasound Elastography measurements between non-presbyopic and presbyopic subjects\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAlthough refraction error was slightly\u0026nbsp;lower in the non-presbyopic group (42%; n = 21) relative to the presbyopic group (58%, n = 29), the difference was not statistically significant (p = 0.211). (Table 2). Remarkably, a conspicuous preponderance of myopia was discerned, constituting a substantial 84% of the entirety of documented refractive errors within the investigated cohort.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePresbyopic subjects (2.73\u0026plusmn;0.88 D) recorded significantly lower AA compared to the non-presbyopic group (2.73\u0026plusmn;0.88 D) (p \u0026lt;0.001). The AA in the presbyopic subjects was even lower than the normal range (4D \u0026ndash; 8D).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA high proportion of the subjects (47.6%, n = 40) had insufficient AA, 35.7% ( n = 30) had a normal AA, and 16.7% (n = 14) had excess AA. All the participants with insufficient AA were presbyopia subjects, while those with excess AA were all non-presbyopic subjects. The proportion of those with normal AA was higher among non-presbyopic (86.7%, n =26) compared to presbyopia subjects (13.3%, n = 4) (p\u0026lt;0.001)\u003c/p\u003e\n\u003cp\u003eThe average degree of presbyopia was 0.83\u0026plusmn;0.87 SD, and the value (mean difference (SD) = -1.58 (0.03), p \u0026lt;0.001) was significantly different between the two groups. Subjects with presbyopia displayed a markedly higher elasticity mean of 13.21 \u0026plusmn; 2.09 kPa, surpassing both the overall mean and the elasticity observed in the non-presbyopic group. Meanwhile, individuals without presbyopia exhibited a significantly lower lens intensity (26.35 \u0026plusmn; 2.98 AU, p = 0.002) compared to the presbyopic subjects (28.34 \u0026plusmn; 2.76 AU).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eUltrasound elastography data from the non-presbyopic cohort demonstrated a significantly lower mean elasticity value (6.98 kPa) relative to the presbyopic subgroup (13.21 kPa).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn contrast, axial length, lens thickness, and lens volume were not significantly different (p\u0026gt;0.05) between the two groups. These results underscore the subtle nature of the variation in these biometric parameters between the two groups, suggesting that presbyopia may not affect these metrics.\u003c/p\u003e\n\u003cp id=\"_Toc164851364\"\u003e\u003cstrong\u003eTable 2: Ultrasound Elastography measurements between non-presbyopic and presbyopic patients\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrequency (percentage)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026chi;\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMD (SE)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003et-test\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAll\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNon-Prebyopic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePresbyopic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eRefraction error\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e50 (40.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21(42.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e29(58.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.211\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e34 (59.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19(55.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15(44.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAmplitude of accommodation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.25\u0026plusmn;3.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8.03\u0026plusmn;2.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.73\u0026plusmn;0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.3 (0.02)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eInsufficiency\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40 (47.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40 (100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e70.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNormal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30(35.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26(86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4 (13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eExcess\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e14(16.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e14 (100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eDegree of presbyopia\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.83\u0026plusmn;0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.58\u0026plusmn;0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-1.58 (0.03)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-20.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMild (\u0026lt;+1.25D)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25(60.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11(21.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e49.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eModerate (+1.25D - +2.0D)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27(22.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e19(100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAdvance (\u0026gt;+2.0D)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13(16.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e14(100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAxial length (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.77\u0026plusmn;1.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.75\u0026plusmn;0.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.79\u0026plusmn;1.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.03 (0.22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.146\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.884\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLens thickness (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.96\u0026plusmn;0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.89\u0026plusmn;0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.02\u0026plusmn;0.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.13 (0.07)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-1.972\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.052\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLens volume (cm\u003csup\u003e3\u003c/sup\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.003 (0.002)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.049\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.297\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eElasticity degree (kPa)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.24\u0026plusmn;3.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.98\u0026plusmn;1.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.21\u0026plusmn;2.09\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-6.23 (0.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-14.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLens intensity\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27.39\u0026plusmn;3.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26.35\u0026plusmn;2.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e28.34\u0026plusmn;2.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-1.99 (0.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-3.181\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.002*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eElasticity degree (kPa)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.24\u0026plusmn;3.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.98\u0026plusmn;1.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.21\u0026plusmn;2.09\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-6.23 (0.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-14.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eMD = mean difference, SE = standard error\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eAssociation between age and biometric parameters\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo difference was observed in the visual acuity and refractive error between age groups. However, the mean AA reduced significantly as age increased (p\u0026lt;0.001). After 40 years old, a significant proportion of subjects had insufficient AA. Likewise, the mean degree of presbyopia increased significantly with age (p \u0026lt;0.001). Among subjects above 50 years old, 64.3% had an advanced degree of presbyopia compared to the younger age groups (p \u0026lt;0.001). Elasticity degree and lens thickness increased significantly with age (p = 0.005), and also differed significantly across age groups. \u0026nbsp; Nevertheless, despite axial length and lens volume increasing significantly with age, both parameters demonstrated no significant difference across age groups.\u0026nbsp;\u003c/p\u003e\n\u003cp id=\"_Toc164851373\"\u003e\u003cstrong\u003eTable 3:\u003c/strong\u003e Biometric parameters across various age groups\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (years old)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026chi;\u003csup\u003e2\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e19-30\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e31-39\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e40-50\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003e51-60\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eVisual acuity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6/12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(100.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.989\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6/9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3(60.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6/6\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13(16.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27(34.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30(38.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8(10.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eRefraction Error\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8(16.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15(30.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20(40.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7(14.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.928\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.588\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5(14.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15(44.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11(32.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3(8.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eAmplitude of accommodation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.69\u0026plusmn;2.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.88\u0026plusmn;2.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.82\u0026plusmn;0.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.13\u0026plusmn;0.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e76.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eInsufficiency\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(2.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30(75.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9(22.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e85.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNormal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5(16.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23(76.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1(3.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eExcess\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8(57.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6(42.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003eDegree of Presbyopia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMean \u0026plusmn; SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1.42\u0026plusmn;0.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.25\u0026plusmn;0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e205.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMild (\u0026lt;+1.25D)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11 (25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e90.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eModerate\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(+1.25D - +2.0D)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27 (62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAdvance (\u0026gt;+2.0D)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0 (0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6(13)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAxial length (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.69\u0026plusmn;0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.82\u0026plusmn;1.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.63\u0026plusmn;0.86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e24.16\u0026plusmn;1.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.741\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.531\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLens thickness (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.73\u0026plusmn;0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.93\u0026plusmn;0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.01\u0026plusmn;0.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.16\u0026plusmn;0.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.681\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.005*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLens volume (cm\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.10\u0026plusmn;0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.591\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.623\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eElasticity degree (kPa)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.63\u0026plusmn;1.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7.47\u0026plusmn;1.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12.78\u0026plusmn;1.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e15.41\u0026plusmn;1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e92.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLens intensity\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25.54\u0026plusmn;2.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26.56\u0026plusmn;2.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e28.32\u0026plusmn;2.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e29.40\u0026plusmn;3.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.656\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 4 presents the bivariate correlation between age and biometric parameters. Accommodation displayed a significant, inverse and strong correlation with age (r = -0.89), whereas the degree of presbyopia correlated strongly and positively with age (r = 0.75). Lens thickness had a significant and moderate correlation with age (r = 0.38). Axial length and lens volume depicted no correlation with age.\u003c/p\u003e\n\u003cp id=\"_Toc164851375\"\u003e\u003cstrong\u003eTable 4:\u003c/strong\u003e Correlation analysis of biometric parameters, presbyopia measurement and age\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (years old)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBivariate correlation (r)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAccommodation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.892\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eDegree of Presbyopia\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.889\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAxial length\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.035\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.749\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLens thickness\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.380\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001**\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLens volume\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.949\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e**. Correlation is significant at the 0.01 level (2-tailed).\u003c/p\u003e\n\u003cp\u003eRelationship between lens elasticity degree, refractive error, and biometric parameters\u003c/p\u003e\n\u003cp\u003eAs shown in Table 5, no relationship was observed between\u0026nbsp;refraction error and lens elasticity degree (p = 0.667), indicating that the lens elasticity degree is unaffected by refraction errors. Meanwhile, lens accommodation depicted a negative and strong correlation with lens elasticity degree (r = -0.85); however, upon adjusting for age, a weak negative correlation was detected (p = -0.27). The degree of presbyopia showed a direct, strong and significant correlation with lens elasticity degree (r = 0.88), and the relationship was moderate (r = 0.54) after being adjusted for age. Lens thickness displayed a weak but significant correlation with lens elasticity degree (p = 0.27), but the relationship was not significant after controlling for age. Detailed description of the linear relationship between the variables is provided in the Supplementary file.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 7:\u003c/strong\u003e Bivariate and partial correlation analysis of presbyopia measurement, lens elasticity degree\u0026nbsp;and biometric parameters\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLens elasticity degree\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBivariate correlation (r)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePartial correlation (r\u003csub\u003epartial\u003c/sub\u003e)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eRefraction error\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.072\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.667\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.052\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.456\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAccommodation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.815\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.274\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.012*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eDegree of Presbyopia\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.880\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.540\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAxial length\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.959\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.044\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.693\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLens thickness\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.268\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.014*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e-0.101\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.363\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe main aim of this study is to investigate the biometric properties and lens elasticity in individuals with non-presbyopia and presbyopia across various age groups. Understanding the biometric properties and lens elasticity in individuals with and without presbyopia holds significant implications in the field of optometry, ophthalmology, and ageing research.\u003c/p\u003e\n\u003cp\u003eIn this study, subjects with presbyopia had a significantly lower amplitude of accommodation compared to non-presbyopic subjects.\u0026nbsp;Presbyopia is a common age-related condition characterised by a progressive decline in the amplitude of accommodation (Kam et al., 2022). Such individuals experience reduced flexibility and efficiency in accommodating to near objects. One primary mechanism in presbyopia is the changes in the composition and properties of the crystalline lens (Kubota et al., 2020). With age, the crystalline lens becomes less elastic and more rigid, impairing its ability to change shape effectively in response to ciliary muscle contraction. This loss of lens flexibility diminishes the eye's ability to adjust its focus for near vision tasks, contributing to presbyopia (Khadka et al., 2022). Another contributing factor is the gradual weakening of the ciliary muscles responsible for controlling lens shape (Cabeza-Gil et al., 2021). With advancing age, the ciliary muscles weaken, leading to diminished contractility and reduced accommodation amplitude (Ithnin et al., 2023; Zhang et al., 2022).\u003c/p\u003e\n\u003cp\u003ePresbyopic subjects also demonstrated a higher lens elasticity degree compared to non-presbyopic subjects. This finding suggests the association between lens elasticity and onset of presbyopia might be shaped by other mechanisms, leading to a paradoxical increase in elasticity among presbyopic individuals. The lens of presbyopic individuals may undergo compensatory changes in response to the loss of accommodative ability (Cacho et al., 2002). As the crystalline lens becomes less elastic with age, adaptations within the lens capsule or alterations in the surrounding structures, such as the ciliary muscle and zonular fibres, may attempt to maintain some degree of flexibility and focusing ability (Zhang et al., 2018). These conditions may lead to a perceived increase in lens elasticity among presbyopic individuals, despite the underlying age-related changes (Zhang et al., 2022).\u003c/p\u003e\n\u003cp\u003eThe static analysis revealed a strong correlation between lens elasticity and the presbyopic cohort, but such a relationship was absent in the non-presbyopic group (Gennisson et al., 2013). This empirical observation lends support to the validation of ultrasound elastography outputs. Within the non-presbyopic cohort, it is posited that accommodation operates optimally and conventionally (Zhang et al., 2022). This comparison is consistent with established physiological parameters, which may exhibit inherent inter-individual variations while consistently maintaining an overarching normal range. Notably, these parameters remain unaffected by the chronological progression of age (Manns et al., 2022). An additional corroborating factor covering the aforementioned theory is the negative correlation between the degree of elasticity and accommodation. As the elasticity of the lens decreases, denoted by higher kPa values and indicative of increased rigidity, a corresponding reduction in accommodation ensues (Detorakis et al., 2013). This inverse relationship underscores the pivotal role of lens biomechanics in the accommodation process.\u003c/p\u003e\n\u003cp\u003eWe found significant correlations between lens elasticity and key variables such as age, accommodation, and the presence of presbyopia. This finding suggests a discernible relationship between these variables, contributing valuable insights into the interplay of these parameters within the ocular system. The consistency between our study and previous research lends credibility to the identified relationships and contributes to the growing body of knowledge in the field (Chen et al., 2021; Fekadu et al., 2021; Liu et al., 2023).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn this study, higher accommodation correlated with lower elasticity, whereas a higher degree of presbyopia and lens thickness was associated with higher lens elasticity. No significant correlation was detected between refractive error and the lens elasticity degree across age groups. The insignificant results may stem from various ways in which refractive errors are manifested, each affecting vision in distinct manners (Bhardwaj \u0026amp; Rajeshbhai, 2013). Furthermore, this finding sheds more light on our preceding observation, where the correlation between lens elasticity degree and axial length, as well as lens thickness, was significant. Collectively, these findings suggest that lens elasticity is moderately influenced by biometric properties.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe proportion of refractive error was higher among presbyopic subjects, aligning with prior research outcomes affirming the pervasive nature of myopia in East Asian populations. For instance, prevalence estimates indicate that over 50% of cases of refractive errors (Majithia et al., 2020). This high prevalence has been consistently observed in countries such as Korea, Japan, Singapore, and China, substantiating the widespread nature of myopia in this region (Kaiti et al., 2020). These findings suggest that the degree of lens elasticity across various age groups is contingent upon the physiological ageing processes occurring within the eye, rather than being attributable to refractive anomalies. Therefore, while the elasticity of the lens can exert an impact on vision, such effects may not be directly associated with refractive errors in the eye. The observed correlations suggest a complex interplay between lens elasticity, age-related changes, and the manifestation of refractive conditions.\u003c/p\u003e\n\u003cp\u003eThe inverse association between accommodation and lens elasticity illustrates the dynamic lens thickness for focal ..s among individuals, with some exhibiting higher levels of elasticity even in the presence of advanced presbyopia. This variability might be influenced by genetic factors, environmental influences, or other unknown variables. Lens power is determined by curvature and refractive index. The optical power of the human eye lens is intricately governed by its curvature and refractive index, important factors orchestrating the lens's ability to focus incident light onto the retina (Bassnett, 2021).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLimitations and recommendations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study is subject to important limitations. All the research modalities and instruments are exclusive to a single hospital, leading to the use of identical devices for outpatient assessments. There were delays given the necessity to conduct assessments during periods of reduced patient activity owing to time constraints. A large sample size was not recruited since the study was restricted to the Ophthalmology and Radiology departments. These distinct yet interconnected sections, situated within proximity, necessitate completion for each participant to finalise the dataset and facilitate report writing. Challenges were faced during certain assessments as the imaging equipment was concurrently utilised by multiple ophthalmologists and patients, leading to extended wait times. In response, these patients opted to defer their participation and agreed to return on the subsequent day. Given the voluntary nature of the data collection, it was incumbent upon the patients to revisit the respective department to complete the data collection or testing process. Despite being beyond the researcher’s control, these issues do not significantly influence the overall outcome. Nonetheless, this limitation reflects the need to accrue a more extensive dataset from the patient cohort.\u003c/p\u003e\n\u003cp\u003eThe lack of comparable research also limits the opportunity for the external validation of our findings. Consequently, this limitation affected the corroboration of the present data with existing literature. Nevertheless, this study serves as a foundational platform for subsequent investigations in the field. The diverse demographic backgrounds of patients, encompassing various ethnicities and age groups, added complexity to the process. Although this diversity did not compromise the accuracy of data collection, it did contribute to an extended duration required for patient interaction and engagement.\u003c/p\u003e\n\u003cp\u003eFor future research, a broader age range is deemed essential to enhance the inclusivity of diverse age groups. A distinct population of cataract patients also warrants consideration to ascertain the elasticity degree and its correlation with cataract grade. Utilising ultrasound elastography images as a reference, there exists an opportunity to establish a novel categorisation and classification of presbyopia grounded in the elasticity degree and its intensity, thus contributing to a refined understanding of this condition. Given the reliance on ultrasound elastography for assessing lens elasticity, ensuring consistency in output values across multiple cases is paramount. Quality assurance measures, including standardised protocols, regular calibration, and ongoing training for operators, should be implemented to maintain precision and reliability in measurements obtained from ultrasound elastography machines.\u003c/p\u003e\n\u003cp\u003eGiven the significant differences observed in age distribution, amplitude of accommodation, and degree of presbyopia between presbyopic and non-presbyopic subjects, it is crucial to implement age-specific screening protocols for early detection and intervention. Regular eye examinations, particularly for individuals approaching middle age and beyond, can aid in identifying presbyopia and initiating appropriate management strategies promptly. Incorporating biometric assessments, including lens elasticity measurements, into routine eye examinations can provide valuable insights into the progression of presbyopia and aid in personalised treatment planning. Clinicians should consider integrating techniques such as lenticular elastography ultrasound to accurately evaluate lens elasticity and monitor changes over time.\u003c/p\u003e\n\u003cp\u003eBased on the observed higher elasticity degree in the presbyopia group compared to the non-presbyopia group, there is a need for further research to explore the underlying mechanisms driving changes in lens elasticity with age. Investigating factors influencing lens elasticity, such as genetic predisposition, lifestyle factors, and environmental influences, can inform the development of targeted interventions aimed at preserving or restoring the function of the human lens.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study revealed significant differences in several biometric parameters between presbyopic and non-presbyopic subjects, highlighting the influence of age-related changes on ocular characteristics. With advancing age, the amplitude of accommodation reduced progressively while the degree of presbyopia increased. Additionally, lens thickness, elasticity degree, and lens intensity were found to significantly increase with age, indicating age-related changes in the biomechanical properties of the lens. Presbyopic individuals exhibited higher elasticity degrees, with the elasticity degree increasing significantly with age. Correlation analyses further revealed strong associations between lens elasticity and factors such as lens accommodation and the degree of presbyopia. These findings underscore the potential utility of biometric properties as reliable indicators of lens elasticity, particularly in the context of presbyopia. Understanding the relationship between these parameters could aid in the development of innovative and cost-effective markers for early detection and management of presbyopia.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflict of Interest\u003c/h2\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eFunds\u003c/h2\u003e\u003cp\u003eNone\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConception and design: AHQ, NBB, RBMSAnalysis and interpretation of the data: EBA, MBMZ, AHQDrafting of the article: AHQCritical revision of the article for important intellectual content: AHQ, NBB, RBMS, EBAFinal approval of the article: AHQ, AHQ, NBB, RBMS, EBA, MBMZProvision of study materials or patients: AHQ, NBB, RBMSStatistical expertise: AHQ, NBBAdministrative, technical, or logistic support: NBBCollection and assembly of data: AHQ\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData will be made available upon request from the authors\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBerdahl, J., Bala, C., Dhariwal, M., Lemp-Hull, J., Thakker, D., \u0026amp; Jawla, S. (2020). Patient and economic burden of presbyopia: a systematic literature review. \u003cem\u003eClinical Ophthalmology\u003c/em\u003e, 3439\u0026ndash;3450.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBhardwaj, V., \u0026amp; Rajeshbhai, G. P. (2013). Axial length, anterior chamber depth-a study in different age groups and refractive errors. Journal of clinical and diagnostic research: JCDR, 7(10), 2211.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBassnett, S. (2021). Zinn's zonule. \u003cem\u003eProgress in retinal and eye research\u003c/em\u003e, \u003cem\u003e82\u003c/em\u003e, 100902.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBontzos, G., Douglas, V. P., Douglas, K. A., Kapsala, Z., Drakonaki, E. E., \u0026amp; Detorakis, E. T. (2021). Ultrasound elastography in ocular and periocular tissues: A review. \u003cem\u003eCurrent Medical Imaging\u003c/em\u003e, \u003cem\u003e17\u003c/em\u003e(9), 1041\u0026ndash;1053.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen, P. Y., Shih, C. C., Lin, W. C., Ma, T., Zhou, Q., Shung, K. K., \u0026amp; Huang, C. C. (2018). High-resolution shear wave imaging of the human cornea using a dual-element transducer. \u003cem\u003eSensors\u003c/em\u003e, \u003cem\u003e18\u003c/em\u003e(12), 4244.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChrzanowski KT. Measurement of eyepiece diopter of direct view imagers. \u003cem\u003eOpto-Electronics Rev\u003c/em\u003e. 2020;28. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://dx.doi.org/10.24425/opelre.2020.135373\u003c/span\u003e\u003cspan address=\"10.24425/opelre.2020.135373\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCabeza-Gil, I., Grasa, J., \u0026amp; Calvo, B. (2021). A numerical investigation of changes in lens shape during accommodation. \u003cem\u003eScientific Reports\u003c/em\u003e, \u003cem\u003e11\u003c/em\u003e(1), 9639.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eCacho, P., Garc\u0026iacute;a, A., Lara, F., \u0026amp; Segu\u0026iacute;, M. (2002). Diagnostic signs of accommodative insufficiency. \u003cem\u003eOptometry and Vision Science\u003c/em\u003e, \u003cem\u003e79\u003c/em\u003e(9), 614\u0026ndash;620.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChen, L. J., Chang, Y. J., Shieh, C. F., Yu, J. H., \u0026amp; Yang, M. C. (2021). Relationship between practices of eye protection against solar ultraviolet radiation and cataract in a rural area. \u003cem\u003ePloS one\u003c/em\u003e, \u003cem\u003e16\u003c/em\u003e(7), e0255136.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDu Toit, R. (2006). How to prescribe spectacles for presbyopia. \u003cem\u003eCommunity Eye Health\u003c/em\u003e, \u003cem\u003e19\u003c/em\u003e(57), 12.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eFekadu, S. A., Seid, M. A., Akalu, Y., Gela, Y. Y., Diress, M., Getnet, M., \u0026hellip; Belsti, Y. (2022). Factors associated with diabetic retinopathy screening and regular eye checkup practice among diabetic patients attending Felege Hiwot Specialized Hospital. \u003cem\u003eInternational Journal of Ophthalmology\u003c/em\u003e, \u003cem\u003e15\u003c/em\u003e(11), 1829.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGennisson, J. L., Deffieux, T., Fink, M., \u0026amp; Tanter, M. (2013). Ultrasound elastography: principles and techniques. \u003cem\u003eDiagnostic and interventional imaging\u003c/em\u003e, \u003cem\u003e94\u003c/em\u003e(5), 487\u0026ndash;495.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGlasser, A. (2006). Accommodation: mechanism and measurement. \u003cem\u003eOphthalmol Clin North Am\u003c/em\u003e, \u003cem\u003e19\u003c/em\u003e(1), 1\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIthnin, M. H., Othman, S. F., Abd Aziz, N. A., \u0026amp; Adnan, M. A. H. M. (2023). The Status Of Myopia Refractive Error From 2018 Until 2021 Among Aged 30 To 35 Years Old In A Private Optometry Practice, Dungun, Malaysia: Retrospective Data. \u003cem\u003eInternational Journal Of Allied Health Sciences\u003c/em\u003e, \u003cem\u003e7\u003c/em\u003e(5).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKaiti, R., Shyangbo, R., Sharma, I. P., \u0026amp; Dahal, M. (2021). Review on current concepts of myopia and its control strategies. \u003cem\u003eInternational Journal of Ophthalmology\u003c/em\u003e, \u003cem\u003e14\u003c/em\u003e(4), 606.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKam, K. W., Pang, C. P., \u0026amp; Yam, J. C. (2022). Refractive Errors, Myopia, and Presbyopia. \u003cem\u003eOphthalmic Epidemiology\u003c/em\u003e, 87\u0026ndash;112.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKatz, J. A., Karpecki, P. M., Dorca, A., Chiva-Razavi, S., Floyd, H., Barnes, E., \u0026hellip; Donnenfeld, E. (2021). Presbyopia\u0026ndash;A review of current treatment options and emerging therapies. \u003cem\u003eClinical Ophthalmology\u003c/em\u003e, 2167\u0026ndash;2178.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKhadka, N. K., Timsina, R., \u0026amp; Mainali, L. (2022). An AFM Approach Applied in a Study of α-Crystallin Membrane Association: New Insights into Lens Hardening and Presbyopia Development. \u003cem\u003eMembranes\u003c/em\u003e, \u003cem\u003e12\u003c/em\u003e(5), 522.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKubota, M., Kubota, S., Kobashi, H., Ayaki, M., Negishi, K., \u0026amp; Tsubota, K. (2020). Difference in pupillary diameter as an important factor for evaluating amplitude of accommodation: a prospective observational study. \u003cem\u003eJournal of Clinical Medicine\u003c/em\u003e, \u003cem\u003e9\u003c/em\u003e(8), 2678.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee, A. C., Qazi, M. A., \u0026amp; Pepose, J. S. (2008). Biometry and intraocular lens power calculation. \u003cem\u003eCurrent opinion in ophthalmology\u003c/em\u003e, \u003cem\u003e19\u003c/em\u003e(1), 13\u0026ndash;17.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLe\u0026oacute;n, A., Rosenfield, M., Medrano, S. M., Dur\u0026aacute;n, S. C., \u0026amp; Pinz\u0026oacute;n, C. V. (2024). Objective and subjective assessment of accommodative insufficiency. \u003cem\u003eOptometry and Vision Science\u003c/em\u003e, \u003cem\u003e101\u003c/em\u003e(1), 44\u0026ndash;54.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLiu, M. X., Li, D. L., Yin, Z. J., Li, Y. Z., Zheng, Y. J., Qin, Y., \u0026hellip; Pan, C. W. (2023). Smoking, alcohol consumption and corneal biomechanical parameters among Chinese university students. \u003cem\u003eEye\u003c/em\u003e, \u003cem\u003e37\u003c/em\u003e(13), 2723\u0026ndash;2729.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMajithia, S., Wong, K. H., Chee, M. L., Soh, Z. D., Thakur, S., Fang, X. L., \u0026hellip; Cheng, C. Y. (2020). Normative patterns and factors associated with presbyopia progression in a multiethnic Asian population: the Singapore Epidemiology of Eye Diseases Study. \u003cem\u003eBritish Journal of Ophthalmology\u003c/em\u003e, \u003cem\u003e104\u003c/em\u003e(11), 1591\u0026ndash;1595.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eManns, F., Durkee, H. A., Chang, Y. C., Mesquita, G. M., Williams, S., Cabot, F., \u0026hellip; Parel, J. M. A. (2020). Effect of inter-individual accondas in ocular parameters on optical and mechanical accommodation efficiency. \u003cem\u003eInvestigative Ophthalmology \u0026amp; Visual Science\u003c/em\u003e, \u003cem\u003e61\u003c/em\u003e(7), 4637\u0026ndash;4637.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMcDonald, M. B., Barnett, M., Gaddie, I. B., Karpecki, P., Mah, F., Nichols, K. K., \u0026amp; Trattler, W. B. (2022). Classification of presbyopia by severity. \u003cem\u003eOphthalmology and therapy\u003c/em\u003e, \u003cem\u003e11\u003c/em\u003e(1), 1\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOğurel, T., \u0026amp; Burulday, V. (2020). Strain and Shear Wave Elastography in Diagnosis of Retrobulbar Neuritis. \u003cem\u003eJournal of neuro-ophthalmology: the official journal of the North American Neuro-Ophthalmology Society\u003c/em\u003e, \u003cem\u003e40\u003c/em\u003e(2), 169\u0026ndash;173.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSigrist, R. M. S., Liau, J., Kaffas, A. E., Chammas, M. C., \u0026amp; Willmann, J. K. (2017). Ultrasound elastography: review of techniques and clinical applications. Theranostics 7: 1303\u0026ndash;1329.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZemanov\u0026aacute;, M. (2019). Shear wave elastography in ophthalmic diagnosis. \u003cem\u003eJournal Fran\u0026ccedil;ais d'Ophtalmologie\u003c/em\u003e, \u003cem\u003e42\u003c/em\u003e(1), 73\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSong, J. S., Hyon, J. Y., \u0026amp; Jeon, H. S. (2020). Comparison of ocular biometry and refractive outcomes using IOL master 500, IOL master 700, and Lenstar LS900. \u003cem\u003eKorean journal of ophthalmology: KJO\u003c/em\u003e, \u003cem\u003e34\u003c/em\u003e(2), 126\u0026ndash;132.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang, H., Singh, M., Zvietcovich, F., Larin, K. V., \u0026amp; Aglyamov, S. R. (2022). Age-related viscoelasticity changes in rabbit lens measured by optical coherence elastography. \u003cem\u003eOptical Elastography and Tissue Biomechanics VIV\u003c/em\u003e, 11962 (24\u0026ndash;30).\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang, X., Wang, Q., Lyu, Z., Gao, X., Zhang, P., Lin, H., \u0026hellip; Chen, X. (2018). Noninvasive assessment of age-related stiffness of crystalline lenses in a rabbit model using ultrasound elastography. \u003cem\u003eBiomedical Engineering Online\u003c/em\u003e, \u003cem\u003e17\u003c/em\u003e(1), 1\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhu, Y., Zhong, Y., \u0026amp; Fu, Y. (2022). The effects of premium intraocular lenses on presbyopia treatments. \u003cem\u003eAdvances in Ophthalmology Practice and Research\u003c/em\u003e, \u003cem\u003e2\u003c/em\u003e(1), 100042.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Axial length, lens thickness, presbyopia, ultrasound elastography, refractive error","lastPublishedDoi":"10.21203/rs.3.rs-7933992/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7933992/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003ePresbyopia is the loss of near vision that occurs with ageing due to changes in the lens elasticity and muscle function within the eye. However, the influence of biometric properties and the occurrence of presbyopia are not fully understood.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e\u003cp\u003eThis study investigates the correlation between biometric properties and lens elasticity in individuals with non-presbyopia and presbyopia across various age groups.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThe study was conducted at the ophthalmology and radiology departments of a large teaching hospital in Selangor, Malaysia. Using a cross-sectional approach, 84 subjects were recruited, with 44 presbyopic and 40 non-presbyopic subjects. The subjects were screened for biometric properties and lens elasticity. Participant eligibility was determined through various tests, including the assessment of refractive errors and visual acuity. Lens thickness and axial length were measured after the best eye was chosen for testing. The eyes were then scanned utilising ultrasound elastography with shear wave technology. Data were analysed using descriptive statistics and Pearson correlation tests.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eBiometric parameters such as amplitude of accommodation (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), degree of presbyopia (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), lens elasticity (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and lens intensity (p\u0026thinsp;=\u0026thinsp;0.002) were significantly different between the presbyopic and non-presbyopic subjects. The amplitude of accommodation reduced significantly (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) with age, while the degree of presbyopia increased with age compared to younger age subjects (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The mean lens thickness (p\u0026thinsp;=\u0026thinsp;0.005), elastic degree (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and lens intensity (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) increased significantly with advancing age. The elasticity degree was significantly higher in the presbyopia group compared to the non-presbyopia group (13.21\u0026thinsp;\u0026plusmn;\u0026thinsp;2.09 kPa vs. 6.98\u0026thinsp;\u0026plusmn;\u0026thinsp;1.73 kPa; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Lens accommodation correlated inversely with lens elasticity degree, whereas the degree of presbyopia correlated positively with lens elasticity degree.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eBiometric properties are promising and reliable indicators in determining lens elasticity and its association with presbyopia. A diagnostic prospective cohort study may be considered in future research to confirm this finding. Such information may assist in developing innovative and cost-effective markers for the early prevention and management of presbyopia.\u003c/p\u003e","manuscriptTitle":"Correlation of Ultrasonic Elastography of the Lens With Refractive Error and Biometric Parameters in Non-presbyopic and Presbyopic Patients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-10 11:23:29","doi":"10.21203/rs.3.rs-7933992/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cf901900-dd11-4b78-9b7b-63c113cec598","owner":[],"postedDate":"November 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-21T13:53:51+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-10 11:23:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7933992","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7933992","identity":"rs-7933992","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}