Distribution of Refractive, Anterior Corneal and Ocular Residual Astigmatism in Children with Idiopathic Congenital Nystagmus - A Cross-Sectional study

Distribution of Refractive, Anterior Corneal and Ocular Residual Astigmatism in Children with Idiopathic Congenital Nystagmus - A Cross-Sectional study | 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 Distribution of Refractive, Anterior Corneal and Ocular Residual Astigmatism in Children with Idiopathic Congenital Nystagmus - A Cross-Sectional study Dikshya Khadka, Romans Chaudhary, Hari Prasad Upadhyay, Swarswati Khadka, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8472010/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 Idiopathic nystagmus is a developmental oculomotor dysfunction. Individuals with ICN showed a higher rate of astigmatism compared to typically developing children. The aim of the study was to determine the distributions of refractive, corneal, and ocular residual astigmatism in children with idiopathic congenital nystagmus (ICN). Methods Refractive astigmatism (RA) was obtained from objective cycloplegic refraction. Anterior corneal astigmatism (ACA)was determined by a hand-held keratometer. Thibos vector analysis was used to calculate ocular residual astigmatism(ORA). All the patients were divided into the following groups: preschool (2–4 years), school-age (5–12 years) and adolescents (13–18 years) years. Results A total of 218 patients, 149 (68.3%), were male, and 69 (31.7%) were female. The mean ± SD age of patients was 7.29 ± 3.96 years (range 2–18years). The overall prevalence and median value of (RA) was 156 (71.6%) CI (65–78), 1D that of ACA was 166 (76.1%) CI (70–81), 1.5D and that of ORA was 136 (62.4%) CI (56–68),1D respectively. In terms of magnitude, the prevalence of RA was moderate 81 (37.2% ), that of ACA was low 74 (33.9%), and that of ORA was negligible 82 (37.6%). WTR is highly prevalent in RA 110 (50.5%) and ACA 58 (66.1%) whereas ATR 107 (49.1%) is commonly observed among ORA. There was a statistically significant change in axis with age (p < 0.001) but there was a moderate positive correlation between the magnitude of the RA and the ACA (r = 0.416, p = 0.01). Conclusion Children with idiopathic congenital nystagmus had high prevalence of astigmatism involving refractive, anterior corneal and ocular residual astigmatism. WTR astigmatism was predominately presented on refractive and corneal astigmatism whereas ATR was predominance in ORA. So, comprehensive assessment including ACA and ORA is important to accurately diagnose the astigmatic profile and optimize long term clinical management in children with Idiopathic congenital nystagmus. Refractive astigmatism Anterior corneal astigmatism Ocular residual astigmatism Idiopathic congenital nystagmus Figures Figure 1 Background The Idiopathic congenital nystagmus is an oculomotor disorder characterized by rhythmic, involuntary oscillatory movement of the eyes with no underlying ocular abnormalities or neurological disorders[ 1 – 3 ]. It is caused mostly by abnormal development of areas of the brain that control ocular motility and gaze stability[ 3 ]. ICNs can be compatible with both excellent visual acuity and normal binocular vision[ 4 ]. However, ICNs can be associated with refractive error and reduced visual acuity, which presents challenges to visual development. Therefore, it may affect visual performance and, ultimately, the quality of life of children[ 1 , 4 ]. Among refractive errors, the prevalence of astigmatism and its magnitude are greater in the ICN population than in the general pediatric population[ 4 ].The with the rule (WTR) is a more frequent type of astigmatism observed in ICNs during infancy. Although against the rule (ATR) astigmatism is prominent during infancy, it tends to decrease with age in normally developing infants. One study reported that the prevalence and magnitude of astigmatism increase with age among children with ICNs[ 4 , 5 ]. A longitudinal study performed by Jethani et al. on congenital nystagmus demonstrated that children younger than 4 years of age initially had no astigmatism, but they had a 25.2% chance of developing WTR astigmatism during follow-up[ 1 ]. Refractive astigmatism or total astigmatism (RA), anterior corneal astigmatism (ACA) and ocular residual astigmatism (ORA) are different types of astigmatism[ 6 , 7 ]. The RA is a composite of the ACA and ORA. ACA arises from the toric shape of the cornea and ORA is attributed to the posterior corneal surface, crystalline lens, and, to a lesser extent, vitreous and retinal lens with perceptual physiology[ 8 ]. The magnitude of ORA was relatively high among myopic children, whereas it was relatively low in children with astigmatism. However, studies have shown a significant correlation between ACA and ORA[ 7 , 8 ]. A compensatory role of internal astigmatism in reducing corneal astigmatism was noted in preschool children and astigmatic children. Both the ATR and oblique ORA counteract WTR in the ACA among astigmatic patients [ 7 , 9 ]. A previous study reported the pattern and prevalence of refractive astigmatism in ICNs. Therefore, data representing the pattern of astigmatism (anterior corneal astigmatism, ocular residual astigmatism) among ICNs are lacking. Therefore, the aim of this study was to determine the distribution and profile of refractive, corneal, and ocular residual astigmatism in children with idiopathic congenital nystagmus (ICN). Specifically, the current study characterized the magnitude and axis of these astigmatic components and their distribution across pediatric age groups. Materials and methods A hospital-based analytical cross-sectional study was conducted at the pediatric ophthalmology and strabismus department of the Lumbini Eye Institute and Research Center, Nepal, from June 2024 to July 2025. Ethical clearance was obtained from the Institutional Review Committee of Lumbini Eye Institute and Research Center (Reference No. 023/018/19) and follow the guideline of Declaration of Helsinki. The informed written and verbal consent was taken from the participants’ parent before enrollment in the study. For the children age 16–18 years written informed consent was also taken from themselves. This study included all the children aged 2 to 18 years who were diagnosed with ICNs by the pediatric ophthalmologist within the hospital, had no prior history of ocular surgery, and had anatomically normal globe and ocular adenxa. This study excluded children with any anterior or posterior pathologies. Patients younger than two years were not included in our study because of the dramatic changes that occur in astigmatism during the first year of life [ 4 ]. Patient age was subdivided into three groups: preschool (2–4 years), school-age (5–12 years) and adolescent (13–18 years)[ 4 , 10 ]. Definition Astigmatism on the basis of meridians can be classified as simple, compound, mixed-type myopia or hyperopia[ 4 ]. Astigmatism was defined as a cylinder error ≥ 0.75 D[ 11 ]. Astigmatism on the basis of power magnitude was graded as negligible (-2.5D)[ 12 ]. Astigmatism on the basis of the limit of the axis was classified as with-the-rule (axis between 0–30°, 150–180), against-the-rule astigmatism (axis between 60–120°) or oblique astigmatism (axis between 30–60° and 121–149)[ 13 , 14 ]. Clinical examination All patients underwent comprehensive eye examinations, which included visual acuity, slit lamp evaluation, and fundus evaluation. RA or total astigmatism was determined by using two drops of 1% cyclopentolate hydrochloride ophthalmic in each eye in the inferior cavity at five-minute of time intervals. The cycloplegic effect was assured with no fluctuation of the retinoscopic reflex ,loss of direct light reaction and mydriasis. Static retinoscopy was performed after 30 minutes (only after the full cycloplegic effect was achieved)[ 15 ]. ACA was determined with a KM-500, Nidek hand-held auto keratometer. The measurements were performed with the child in a sitting position, blinking before each measurement and with the keratometer held vertically. An experienced optometrist took three consecutive readings from each eye and an average of these three readings was taken and recorded in diopter[ 16 , 17 ]. Data analysis and calculations To ensure the calculation more consistent, all astigmatism component were converted into one format so in this study positive cylinder notation was used for data analysis[ 8 , 18 ]. Therefore, the RA and ACA were converted into positive cylinder notation before calculation. Thibos vector analysis was used to calculate the magnitude and axial direction of ORA[ 19 ]. ORA can be obtained from the vectorial difference between the RA and the ACA vector. Astigmatic measurements of the cylinder (C) and axis (α) were expressed on orthogonal vector components J0 and J45 by using standard formula.[ 7 , 8 , 18 , 19 ] The J0 = (-C/2) * cos(2α) and J45 = (-C/2) * sin(2α) formulas were used to calculate RA and ACA. ORA_vector = RA_vector - ACA_vector formula was used to calculate ORA. The J0_ORA = J0_RA - J0_ACA; J45_ORA = J45_RA - J45_ACA formula was used to calculate the components. The resulting ORA vector components (J0_ORA, J45_ORA) were used for subsequent statistical analysis. Statistical methods Statistical Package for the Social Sciences (SPSS) version 20.0 (IBM, Armonk, NY, USA) was used for the statistical analysis. The non-normally distributed data were expressed as the median value and interquartile range (IQR). A 95% confidence interval (CI)was calculated for different types of astigmatism with their magnitude and axis. Descriptive statistics were performed to determine the distribution of magnitude and axis characteristics and are expressed as percentages and frequencies in the table. Spearman’s rank correlation was used to assess the correlations among the RA, ACA and ORA. There was a strong correlation between the right eye and left eye (r = 0.845), Therefore, only the right eye data were used for statistical analysis. In the inferential statistics to find the association between different types of astigmatism (RA, ACA and ORA) with their magnitude and axis within age group Chi-square test were used. p-value < 0.05 was considered as statistically significant. Results A total of 218 children with idiopathic congenital nystagmus were included; 149 (68.3%) were male, and 69 were female (31.7%). The mean age of the patients was 7.29 ± 3.96 years (range 2–18 years). Among which pre-school, school going and adolescence were 77(35.3%), 116(53.2% and 25(11.5%) respectively. Distribution of astigmatism The overall prevalence of RA was 156 (71.6%) 95% CI, 65.6–78) with median value of 1.5D (IOR 0–2D), that of ACA was 166 (76.1%) CI (70.6–81.7) median 1.5D ( IQR 1–2D), and that of ORA was 136 (62.4%) CI (56.4–68.3) 1.00D median (IQR 0.5–2D). As per the grading of astigmatism, the distribution of RA was moderate 81 (37.2%), ACA was low 74 (33.9%), and ORA was negligible 82 (37.6%) (Table 1 ). According to the orientation of the axis, the distribution of WTR in refractive astigmatism was 110 (50.5%) whereas ATR was 58 (26.6%), and 10 (4.6%) had oblique type refractive astigmatism. Similarly, in anterior corneal astigmatism, out of 144 subjects s (66.1%) presented with WTR 58 (25.7%) ATR, and 7 (3.2%) were having h oblique astigmatism And, in ocular residual astigmatism category, out of 107 subjects, (49.1%) had ATR, 20 (9.2%) had oblique and 18 (8.3%) had WTR (Table 1 ). The distribution of astigmatism based on the position of focal point, 72 (33.0%) had compound hypermetropic astigmatism, 57 (26.1%) had compound myopic astigmatism, 33 (15.1%) had mixed astigmatism, 11 (5.0%) had simple hypermetropic astigmatism, and 10 (4.6%) had simple myopic astigmatism. Distribution of astigmatisms in different age groups The RA, ACA and ORA based on magnitude, whereas ORA based on orientation of the axis did not differ significantly among different age groups (p > 0.05). However, RA (p = 0.02) and ACA (p = 0.004) showed significant change when compared to astigmatism classified based on the orientation of the axis.The magnitude-based classification of astigmatism showed different patterns of astigmatism across age groups. For RA, moderate astigmatism was most common in preschoolers (40%) and school-going children (39%), while adolescents showed a higher prevalence of negligible RA (48%). For ACA, low and moderate levels were equally in preschool children (both 34%), low ACA was common in school-going children (37%), and moderate level of ACA was most common in adolescents (36%). For ORA, negligible categories were more frequent in preschoolers (44%) and adolescents (40%), whereas school-going children showed a higher proportion of low grade ORA (35%). This study also found the distribution of astigmatism based on orientation of axes i.e. WTR, ATR and oblique) among various age groups. In the category of RA, with-the-rule (WTR) astigmatism was the most frequently observed astigmatism among preschool children (58%) and school-going children (50%), while adolescents showed a comparatively higher number of eyes with no astigmatism (44%). For ACA, WTR astigmatism remained the dominant axis across all age groups (64%–67%), though adolescents exhibited a higher number of oblique astigmatism (16%) than the younger groups. In contrast, against-the-rule (ATR) astigmatism was the highly observed axis pattern for ORA, ranging from 45% to 52% across all age groups. Relationship among the magnitudes of the RA, ACA and ORA There was a moderate positive correlation between the magnitude of RA and ACA (r = 0.416, p = 0.01) indicating that increase of ACA power may be associated with increase in RA power. However, there was a weaker positive correlation between the RA and ORA (r = 0.210, p = 0.001). ACA and ORA had moderate positive correlations (r = 0.324, p = 0.001). Overall, all the components of astigmatism e i.e RA, ACA and ORA were statistically significant. Hence, ,it suggests that each component is interrelated with each other with different strengths. The coefficient of determination (R2) and regression equation of magnitude of the RA and ACA was shown in the following scatter diagram (Figure. 2). RA = 0.494 + 0.482 x ACA, R 2 = 0.270) This showed that when ACA is increased by one unit, RA will be increased by 0.482 units. The contribution of ACA in RA was 0.27, i.e 27% variation in RA is explained by ACA while other variation in RA is due to ORA. This relation was found to be statistically significant at the level of 5% . Table 1 Distribution of astigmatism on the basis of magnitude and axis in ICN children (n = 218) Type of astigmatism Prevalence Magnitude n (%) 95% CI (Lower-Upper Axis n (%) 95% CI (Lower-Upper Refractive Astigmatism 156 (71.6%) 95% CI, 65.6–78) Negligible 62(28.4) 22.5–34.4 No Astigmatism 40(18.3) 13.3–23.9 Low 59(27.1) 21.1–33 WTR 110(50.5) 43.6–57.8 Moderate 81(37.2) 31.2–43.1 ATR 58(26.6) 20.7–32.6 High 16(7.3) 4.1–11 Oblique 10(4.6) 1.8–7.8 Anterior Corneal Astigmatism 166 (76.1%) CI (70.6–81.7) Negligible 52(23.9) 17.9–29.8 No Astigmatism 11(5) 2.8–8.3 Low 74(33.9) 27.5–40.4 WTR 144(66.1) 59.2–72 Moderate 60(27.5) 22–33.5 ATR 56(25.7) 20.2–32.1 High 32(14.7) 10.1–19.7 Oblique 7(3.2) 0.9–5.5 Ocular residual Astigmatism 136 (62.4%) CI (56.4–68.3) Negligible 82(37.6) 31.7–44 No Astigmatism 73(33.5) 27.5–39.9 Low 63(28.9) 22.9–34.9 WTR 18(8.3) 4.6–12.4 Moderate 26(11.9) 8.3–16.5 ATR 107(49.1) 42.7–56 High 47(21.6) 16.5–27.1 Oblique 20(9.2) 5.5–13.3 Note : WTR : With The Rule, ATR : Against The Rule Table 2 Association of RA, ACA and ORA across different age groups based on axis and magnitude (n = 218). Characteristic Age group p-value Preschool (n = 77) School-going children (n = 116) Adolescents (n = 25) RA magnitude Group Negligible 18 (23%) 32 (28%) 12 (48%) 0.2 Low 20 (26%) 33 (28%) 6 (24%) Moderate 31 (40%) 45 (39%) 5 (20%) High 8 (10%) 6 (5.2%) 2 (8.0%) ACA magnitude group Negligible 12 (16%) 34 (29%) 6 (24%) 0.11 Low 26 (34%) 43 (37%) 5 (20%) Moderate 26 (34%) 25 (22%) 9 (36%) High 13 (17%) 14 (12%) 5 (20%) ORA magnitude group Negligible 34 (44%) 38 (33%) 10 (40%) 0.3 Low 16 (21%) 41 (35%) 6 (24%) Moderate 8 (10%) 13 (11%) 5 (20%) High 19 (25%) 24 (21%) 4 (16%) ORA Axis group No astigmatism 34 (44%) 32 (28%) 7 (28%) 0.14 WTR 4 (5.2%) 13 (11%) 1 (4.0%) ATR 35 (45%) 59 (51%) 13 (52%) Oblique 4 (5.2%) 12 (10%) 4 (16%) RA Axis group No astigmatism 10 (13%) 19 (16%) 11 (44%) 0.008 WTR 45 (58%) 58 (50%) 7 (28%) ATR 20 (26%) 34 (29%) 4 (16%) Oblique 2 (2.6%) 5 (4.3%) 3 (12%) ACA Axis group No astigmatism 3 (3.9%) 6 (5.2%) 2 (8.0%) 0.04 WTR 50 (65%) 78 (67%) 16 (64%) ATR 23 (30%) 30 (26%) 3 (12%) Oblique 1 (1.3%) 2 (1.7%) 4 (16%) Discussion A hospital-based cross-sectional study aimed to determine the profile of astigmatism (refractive, anterior corneal and ocular residual) in a pediatric population with idiopathic congenital nystagmus. In this study, 71.6% of the ICN children were refractive astigmatism (RA) that was, similar to the study done in idiopathic congenital nystagmus population (65.37%)[ 4 ] and the normal population (13%)[ 13 ], 26.76%[ 20 ]. ACA was the most common type of astigmatism, at 76%, which is comparable to the myopic population (85%) [ 8 ], but it was higher than those reported in the normal population (36.9%)[ 13 ]. However, the prevalence of ORA was (62%), which was greater than a study conducted among myopic children (51.5%)[ 8 ] and preschool children (44.2%) respectively[ 5 ].The prevalence of RA seems to be greater in patients with ICNs than in the normal population. Similarly, In this study the prevalence of ACA among ICN children was similar to myopic children but much higher than normal population [ 8 ]. However, the prevalence of ORA is higher among children with ICN than the children with myopia.The reason could be the higher prevalence of astigmatism among ICN than normal population because the children with ICN shows higher and more diverse refractive anomalies because of early foveal motor instability and associated ocular pathway abnormalities which disturb the emmetropization and produce axial and corneal asymmetries [ 4 , 9 ]. Among the classifications of meridional astigmatism of the RA, compound hypermetropic astigmatism (33%) was frequently observed following compound myopic astigmatism (26.59%), whereas the reverse condition was observed among ICNs, in which compound myopic astigmatism was the most common type (30.72%), followed by compound hypermetropic astigmatism (27%)[ 4 ]. This may be because the current study included a pediatric population (2–18 years), whereas the study of Frencia et al. included ICN patients in the age range of 2–69 years. The current study has median value with prevalence of RA, ACA, and ORA are 1.5D(71.6%), 1.5D(76.1%), 1D (62%) whereas a study conducted at Nanjing among preschool children their median value and prevalence was was 0.25D(14.2%), 1D(56.1%), 1(44.2%) respectively[ 9 ]. This means that children with ICN have higher magnitude of RA, ACA compared with non nystagmus children but interestingly the median of ORA is similar. Prevalence of higher corneal astigmatism may be due to the frequent mechanical interaction between eyelid and cornea occurring due to nystagmoid movement [ 5 , 21 ]. The RA was predominantly moderate grade (37.2%), the ACA was low grade (33.9%), and the ORA was negligible (37.6%), which matched the previously documented patterns [ 9 ]. On the basis of the limits of the axis WTR, ATR, and oblique, WTR was predominant in the ACA (66%) and RA (50.5%), but in the ORA, it was predominant in the ATR (49.1%), which also matched with preschool and myopic children[ 8 ]. This finding indicates a greater dominance of WTR in the cornea, which seems to play a major role in overall refractive astigmatism in ICNs, similar to findings noted among the infantile nystagmus syndrome population. ORA displayed greater dominance of the ATR in approximately half of the total participants, which opposed the ACA. Thus, this study suggests that a compensatory mechanism, most likely from the crystalline lens, can develop. Therefore, ATR can be partially neutralized by WTR astigmatism of the anterior cornea. The magnitude of the ACA and ORA has a moderate positive correlation (r = 0.324), which further supports that the internal compensatory response aligns with the findings of studies on the relationship between corneal and residual astigmatism[ 8 , 9 , 14 ] . The magnitude of astigmatism among age groups did not significantly differ (P > 0.005). However, the axis was significantly different among the different age groups (p < 0.005). This study revealed a shift in the orientation of the axis with age, i.e., a decrease in the WTR RA with age (p = 0.004), and the oblique axis of the ACA increased with age, but there was no difference in the ORA particularly among the astigmatism classified based on the orientation of the axis with the age. Conclusion Children with idiopathic congenital nystagmus presented with high astigmatism involving refractive, anterior corneal and ocular residual astigmatism. WTR astigmatism was predominately presented on refractive and corneal astigmatism whereas ATR was predominance in ORA. Magnitude of astigmatism was remained stable in different age group but the astigmatic axis was statistically significant in age-related shift. So, comprehensive assessment including ACA and ORA is important to accurately diagnose the astigmatic profile and optimize long term clinical management in children with Idiopathic congenital nystagmus. Strength and limitation To the best of our knowledge, this study is novel in reporting the distribution of anterior corneal astigmatism and ocular residual astigmatism in children with nystagmus using vector analysis. Thus, this study provides a better understanding of the underlying mechanisms of astigmatic characteristics than studies that focus solely on refractive error. This Study provides a comprehensive and precise profile of the astigmatic component of a specific clinical population (ICN) of the pediatric age group. An age-stratified approach helped to evaluate the developmental trend of the change of power and axis. However, the lack of a control group, hospital-based sampling, cross sectional study design may limit the generality of the study. This study included only anterior corneal astigmatism, so the contribution of the posterior cornea to total astigmatism was unknown. Therefore, advanced imaging, such as Schiempflug tomography, can help classify posterior corneal and lenticular astigmatism. Furthermore, investigating the impact of astigmatism on quality of life can be done. Abbreviations ICN Idiopathic congenital nystagmus RA Refractive astigmatism ACA Anterior corneal astigmatism ORA Ocular residual astigmatism WTR With the rule ATR Against the rule IQR:Inter-quartile range SD Standard deviation. Declarations Ethics approval and consent to participate: Ethical clearance was obtained from the Institutional Review Committee of Lumbini Eye Institute and Research Center (Reference No. 023/018/19). The research was conducted in accordance with tenets of Declaration of Helsinki. The written informed and verbal consent was taken from the parents before enrollment in the study. For children age 16-18 years written informed consent was also taken from themselves. Consent for publication : Not applicable Availability of data and materials: The datasets used during the current study are available from the corresponding author on reasonable request. Competing Interests: The authors declare that they have no competing interest Funding : No financial disclosure Author Contributions Conceptualization: Dikshya Khadka, Romans Chaudhary, Hari Thapa Data collection: Dikshya Khadka, Swarswati Khadka Formal analysis: Dikshya Khadka, Hari Prasad Upadhyay Investigation: Dikshya Khadka Methodology: Dikshya Khadka, Hari Thapa Supervision: Hari Thapa, Swaraswati Khadka Writing – original draft: Dikshya Khadka Writing – review & editing: Dikshya Khadka, Romans Chaudhary, Hari Prasad Upadhyay, Hari Thapa Acknowledgement Authors would like to express our sincere gratitude to all the participants for their valuable time and contribution to this research. 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Optom Vis Sci Off Publ Am Acad Optom 2002 Sept 1;79:606–13. Thibos LN, Wheeler W, Horner D. Power vectors: an application of Fourier analysis to the description and statistical analysis of refractive error. Optom Vis Sci Off Publ Am Acad Optom. 1997 June;74(6):367–75. Wang Y, Li L, Tang XL, Guo GL, Chen MW, Cha LL et al. Characteristics of astigmatism in school-age children aged 5 to 13 years in northeast Sichuan: a cross-sectional school-based study. Transl Pediatr [Internet]. 2024 July 31 [cited 2025 Dec 7];13(7):1130–40. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11319998/ Shah JR. A Review of Astigmatism - A Refractive Error correctable by Cylindrical glasses. J Drug Deliv Ther [Internet]. 2015 Mar 15 [cited 2025 Dec 9];5(2):29–36. Available from: http://jddtonline.info/index.php/jddt/article/view/1073 Additional Declarations No competing interests reported. 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13:44:58","extension":"xml","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":81509,"visible":true,"origin":"","legend":"","description":"","filename":"8c8ad42c9f61424fbb81f098e0595b021structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8472010/v1/9e3a47e57e708987ea4cecca.xml"},{"id":100689722,"identity":"605aa527-8bcd-4cef-88e4-a99bad143016","added_by":"auto","created_at":"2026-01-20 13:45:27","extension":"html","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":89667,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8472010/v1/d20a6a2d15514ba508d75c88.html"},{"id":100689618,"identity":"6f936c3f-ee1d-4a6c-aef4-d455dd485dbd","added_by":"auto","created_at":"2026-01-20 13:43:54","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":10656,"visible":true,"origin":"","legend":"\u003cp\u003eAssociations between the magnitudes of the ACA and RA\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8472010/v1/b3a6fff88ba9e5a65bd71175.jpg"},{"id":104400096,"identity":"b7501021-7191-436c-b325-7d7616538e3a","added_by":"auto","created_at":"2026-03-11 12:08:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":907392,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8472010/v1/1ea92639-0d0a-4d87-a86e-c398435963ff.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Distribution of Refractive, Anterior Corneal and Ocular Residual Astigmatism in Children with Idiopathic Congenital Nystagmus - A Cross-Sectional study","fulltext":[{"header":"Background","content":"\u003cp\u003eThe Idiopathic congenital nystagmus is an oculomotor disorder characterized by rhythmic, involuntary oscillatory movement of the eyes with no underlying ocular abnormalities or neurological disorders[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. It is caused mostly by abnormal development of areas of the brain that control ocular motility and gaze stability[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. ICNs can be compatible with both excellent visual acuity and normal binocular vision[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, ICNs can be associated with refractive error and reduced visual acuity, which presents challenges to visual development. Therefore, it may affect visual performance and, ultimately, the quality of life of children[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Among refractive errors, the prevalence of astigmatism and its magnitude are greater in the ICN population than in the general pediatric population[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].The with the rule (WTR) is a more frequent type of astigmatism observed in ICNs during infancy. Although against the rule (ATR) astigmatism is prominent during infancy, it tends to decrease with age in normally developing infants. One study reported that the prevalence and magnitude of astigmatism increase with age among children with ICNs[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. A longitudinal study performed by Jethani et al. on congenital nystagmus demonstrated that children younger than 4 years of age initially had no astigmatism, but they had a 25.2% chance of developing WTR astigmatism during follow-up[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Refractive astigmatism or total astigmatism (RA), anterior corneal astigmatism (ACA) and ocular residual astigmatism (ORA) are different types of astigmatism[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The RA is a composite of the ACA and ORA. ACA arises from the toric shape of the cornea and ORA is attributed to the posterior corneal surface, crystalline lens, and, to a lesser extent, vitreous and retinal lens with perceptual physiology[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The magnitude of ORA was relatively high among myopic children, whereas it was relatively low in children with astigmatism. However, studies have shown a significant correlation between ACA and ORA[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. A compensatory role of internal astigmatism in reducing corneal astigmatism was noted in preschool children and astigmatic children. Both the ATR and oblique ORA counteract WTR in the ACA among astigmatic patients [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. A previous study reported the pattern and prevalence of refractive astigmatism in ICNs. Therefore, data representing the pattern of astigmatism (anterior corneal astigmatism, ocular residual astigmatism) among ICNs are lacking. Therefore, the aim of this study was to determine the distribution and profile of refractive, corneal, and ocular residual astigmatism in children with idiopathic congenital nystagmus (ICN). Specifically, the current study characterized the magnitude and axis of these astigmatic components and their distribution across pediatric age groups.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003eA hospital-based analytical cross-sectional study was conducted at the pediatric ophthalmology and strabismus department of the Lumbini Eye Institute and Research Center, Nepal, from June 2024 to July 2025. Ethical clearance was obtained from the Institutional Review Committee of Lumbini Eye Institute and Research Center (Reference No. 023/018/19) and follow the guideline of Declaration of Helsinki. The informed written and verbal consent was taken from the participants\u0026rsquo; parent before enrollment in the study. For the children age 16\u0026ndash;18 years written informed consent was also taken from themselves. This study included all the children aged 2 to 18 years who were diagnosed with ICNs by the pediatric ophthalmologist within the hospital, had no prior history of ocular surgery, and had anatomically normal globe and ocular adenxa. This study excluded children with any anterior or posterior pathologies. Patients younger than two years were not included in our study because of the dramatic changes that occur in astigmatism during the first year of life [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Patient age was subdivided into three groups: preschool (2\u0026ndash;4 years), school-age (5\u0026ndash;12 years) and adolescent (13\u0026ndash;18 years)[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eDefinition\u003c/h2\u003e \u003cp\u003eAstigmatism on the basis of meridians can be classified as simple, compound, mixed-type myopia or hyperopia[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Astigmatism was defined as a cylinder error\u0026thinsp;\u0026ge;\u0026thinsp;0.75 D[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Astigmatism on the basis of power magnitude was graded as negligible (\u0026lt;-0.75D), low (-1D to -1.5D), moderate (-1.5D to -2.5D) and high (\u0026gt;-2.5D)[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Astigmatism on the basis of the limit of the axis was classified as with-the-rule (axis between 0\u0026ndash;30\u0026deg;, 150\u0026ndash;180), against-the-rule astigmatism (axis between 60\u0026ndash;120\u0026deg;) or oblique astigmatism (axis between 30\u0026ndash;60\u0026deg; and 121\u0026ndash;149)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eClinical examination\u003c/h3\u003e\n\u003cp\u003eAll patients underwent comprehensive eye examinations, which included visual acuity, slit lamp evaluation, and fundus evaluation. RA or total astigmatism was determined by using two drops of 1% cyclopentolate hydrochloride ophthalmic in each eye in the inferior cavity at five-minute of time intervals. The cycloplegic effect was assured with no fluctuation of the retinoscopic reflex ,loss of direct light reaction and mydriasis. Static retinoscopy was performed after 30 minutes (only after the full cycloplegic effect was achieved)[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. ACA was determined with a KM-500, Nidek hand-held auto keratometer. The measurements were performed with the child in a sitting position, blinking before each measurement and with the keratometer held vertically. An experienced optometrist took three consecutive readings from each eye and an average of these three readings was taken and recorded in diopter[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eData analysis and calculations\u003c/h3\u003e\n\u003cp\u003eTo ensure the calculation more consistent, all astigmatism component were converted into one format so in this study positive cylinder notation was used for data analysis[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Therefore, the RA and ACA were converted into positive cylinder notation before calculation. Thibos vector analysis was used to calculate the magnitude and axial direction of ORA[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. ORA can be obtained from the vectorial difference between the RA and the ACA vector. Astigmatic measurements of the cylinder (C) and axis (α) were expressed on orthogonal vector components J0 and J45 by using standard formula.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe J0 = (-C/2) * cos(2α) and J45 = (-C/2) * sin(2α) formulas were used to calculate RA and ACA.\u003c/p\u003e \u003cp\u003eORA_vector\u0026thinsp;=\u0026thinsp;RA_vector - ACA_vector formula was used to calculate ORA.\u003c/p\u003e \u003cp\u003eThe J0_ORA\u0026thinsp;=\u0026thinsp;J0_RA - J0_ACA; J45_ORA\u0026thinsp;=\u0026thinsp;J45_RA - J45_ACA formula was used to calculate the components.\u003c/p\u003e \u003cp\u003eThe resulting ORA vector components (J0_ORA, J45_ORA) were used for subsequent statistical analysis.\u003c/p\u003e\n\u003ch3\u003eStatistical methods\u003c/h3\u003e\n\u003cp\u003eStatistical Package for the Social Sciences (SPSS) version 20.0 (IBM, Armonk, NY, USA) was used for the statistical analysis. The non-normally distributed data were expressed as the median value and interquartile range (IQR). A 95% confidence interval (CI)was calculated for different types of astigmatism with their magnitude and axis. Descriptive statistics were performed to determine the distribution of magnitude and axis characteristics and are expressed as percentages and frequencies in the table. Spearman\u0026rsquo;s rank correlation was used to assess the correlations among the RA, ACA and ORA. There was a strong correlation between the right eye and left eye (r\u0026thinsp;=\u0026thinsp;0.845), Therefore, only the right eye data were used for statistical analysis. In the inferential statistics to find the association between different types of astigmatism (RA, ACA and ORA) with their magnitude and axis within age group Chi-square test were used. p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered as statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 218 children with idiopathic congenital nystagmus were included; 149 (68.3%) were male, and 69 were female (31.7%). The mean age of the patients was 7.29\u0026thinsp;\u0026plusmn;\u0026thinsp;3.96 years (range 2\u0026ndash;18 years). Among which pre-school, school going and adolescence were 77(35.3%), 116(53.2% and 25(11.5%) respectively.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eDistribution of astigmatism\u003c/h2\u003e \u003cp\u003eThe overall prevalence of RA was 156 (71.6%) 95% CI, 65.6\u0026ndash;78) with median value of 1.5D (IOR 0\u0026ndash;2D), that of ACA was 166 (76.1%) CI (70.6\u0026ndash;81.7) median 1.5D ( IQR 1\u0026ndash;2D), and that of ORA was 136 (62.4%) CI (56.4\u0026ndash;68.3) 1.00D median (IQR 0.5\u0026ndash;2D). As per the grading of astigmatism, the distribution of RA was moderate 81 (37.2%), ACA was low 74 (33.9%), and ORA was negligible 82 (37.6%) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). According to the orientation of the axis, the distribution of WTR in refractive astigmatism was 110 (50.5%) whereas ATR was 58 (26.6%), and 10 (4.6%) had oblique type refractive astigmatism. Similarly, in anterior corneal astigmatism, out of 144 subjects s (66.1%) presented with WTR 58 (25.7%) ATR, and 7 (3.2%) were having h oblique astigmatism And, in ocular residual astigmatism category, out of 107 subjects, (49.1%) had ATR, 20 (9.2%) had oblique and 18 (8.3%) had WTR (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe distribution of astigmatism based on the position of focal point, 72 (33.0%) had compound hypermetropic astigmatism, 57 (26.1%) had compound myopic astigmatism, 33 (15.1%) had mixed astigmatism, 11 (5.0%) had simple hypermetropic astigmatism, and 10 (4.6%) had simple myopic astigmatism.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eDistribution of astigmatisms in different age groups\u003c/h3\u003e\n\u003cp\u003eThe RA, ACA and ORA based on magnitude, whereas ORA based on orientation of the axis did not differ significantly among different age groups (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). However, RA (p\u0026thinsp;=\u0026thinsp;0.02) and ACA (p\u0026thinsp;=\u0026thinsp;0.004) showed significant change when compared to astigmatism classified based on the orientation of the axis.The magnitude-based classification of astigmatism showed different patterns of astigmatism across age groups. For RA, moderate astigmatism was most common in preschoolers (40%) and school-going children (39%), while adolescents showed a higher prevalence of negligible RA (48%). For ACA, low and moderate levels were equally in preschool children (both 34%), low ACA was common in school-going children (37%), and moderate level of ACA was most common in adolescents (36%). For ORA, negligible categories were more frequent in preschoolers (44%) and adolescents (40%), whereas school-going children showed a higher proportion of low grade ORA (35%). This study also found the distribution of astigmatism based on orientation of axes i.e. WTR, ATR and oblique) among various age groups. In the category of RA, with-the-rule (WTR) astigmatism was the most frequently observed astigmatism among preschool children (58%) and school-going children (50%), while adolescents showed a comparatively higher number of eyes with no astigmatism (44%). For ACA, WTR astigmatism remained the dominant axis across all age groups (64%\u0026ndash;67%), though adolescents exhibited a higher number of oblique astigmatism (16%) than the younger groups. In contrast, against-the-rule (ATR) astigmatism was the highly observed axis pattern for ORA, ranging from 45% to 52% across all age groups.\u003c/p\u003e\n\u003ch3\u003eRelationship among the magnitudes of the RA, ACA and ORA\u003c/h3\u003e\n\u003cp\u003eThere was a moderate positive correlation between the magnitude of RA and ACA (r\u0026thinsp;=\u0026thinsp;0.416, p\u0026thinsp;=\u0026thinsp;0.01) indicating that increase of ACA power may be associated with increase in RA power. However, there was a weaker positive correlation between the RA and ORA (r\u0026thinsp;=\u0026thinsp;0.210, p\u0026thinsp;=\u0026thinsp;0.001). ACA and ORA had moderate positive correlations (r\u0026thinsp;=\u0026thinsp;0.324, p\u0026thinsp;=\u0026thinsp;0.001). Overall, all the components of astigmatism e i.e RA, ACA and ORA were statistically significant. Hence, ,it suggests that each component is interrelated with each other with different strengths. The coefficient of determination (R2) and regression equation of magnitude of the RA and ACA was shown in the following scatter diagram (Figure. 2).\u003c/p\u003e \u003cp\u003eRA\u0026thinsp;=\u0026thinsp;0.494\u0026thinsp;+\u0026thinsp;0.482 x ACA, R\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.270)\u003c/p\u003e \u003cp\u003eThis showed that when ACA is increased by one unit, RA will be increased by 0.482 units. The contribution of ACA in RA was 0.27, i.e 27% variation in RA is explained by ACA while other variation in RA is due to ORA. This relation was found to be statistically significant at the level of 5% .\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDistribution of astigmatism on the basis of magnitude and axis in ICN children (n\u0026thinsp;=\u0026thinsp;218)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eType of astigmatism\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePrevalence\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMagnitude\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e95% CI (Lower-Upper\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eAxis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003en (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e95% CI (Lower-Upper\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eRefractive Astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e156 (71.6%) 95% CI, 65.6\u0026ndash;78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegligible\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e62(28.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22.5\u0026ndash;34.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNo Astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e40(18.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e13.3\u0026ndash;23.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e59(27.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21.1\u0026ndash;33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eWTR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e110(50.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e43.6\u0026ndash;57.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e81(37.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e31.2\u0026ndash;43.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eATR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e58(26.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20.7\u0026ndash;32.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16(7.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.1\u0026ndash;11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOblique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10(4.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1.8\u0026ndash;7.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eAnterior Corneal Astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e166 (76.1%) CI (70.6\u0026ndash;81.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegligible\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e52(23.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e17.9\u0026ndash;29.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNo Astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e11(5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.8\u0026ndash;8.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e74(33.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e27.5\u0026ndash;40.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eWTR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e144(66.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e59.2\u0026ndash;72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60(27.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22\u0026ndash;33.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eATR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e56(25.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20.2\u0026ndash;32.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e32(14.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10.1\u0026ndash;19.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOblique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e7(3.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.9\u0026ndash;5.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eOcular residual Astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e136 (62.4%) CI (56.4\u0026ndash;68.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNegligible\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e82(37.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e31.7\u0026ndash;44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNo Astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e73(33.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e27.5\u0026ndash;39.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e63(28.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22.9\u0026ndash;34.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eWTR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e18(8.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.6\u0026ndash;12.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26(11.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.3\u0026ndash;16.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eATR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e107(49.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e42.7\u0026ndash;56\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e47(21.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e16.5\u0026ndash;27.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eOblique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e20(9.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e5.5\u0026ndash;13.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c8\" namest=\"c2\"\u003e \u003cp\u003eNote : WTR : With The Rule, ATR : Against The Rule\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eAssociation of RA, ACA and ORA across different age groups based on axis and magnitude\u003c/b\u003e (n\u0026thinsp;=\u0026thinsp;218).\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eCharacteristic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eAge group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreschool (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSchool-going children (n\u0026thinsp;=\u0026thinsp;116)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAdolescents (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRA magnitude Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNegligible\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (23%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32 (28%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12 (48%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20 (26%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33 (28%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (24%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31 (40%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e45 (39%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (20%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (5.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (8.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eACA magnitude group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNegligible\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (16%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34 (29%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (24%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26 (34%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e43 (37%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (20%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26 (34%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (22%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9 (36%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (17%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (12%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (20%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eORA magnitude group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNegligible\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34 (44%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e38 (33%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10 (40%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16 (21%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e41 (35%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6 (24%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eModerate\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (11%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5 (20%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19 (25%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24 (21%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (16%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eORA Axis group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34 (44%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32 (28%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (28%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWTR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (5.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (11%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1 (4.0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eATR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35 (45%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e59 (51%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13 (52%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOblique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (5.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (10%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (16%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eRA Axis group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (13%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (16%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11 (44%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.008\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWTR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45 (58%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e58 (50%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7 (28%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eATR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20 (26%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34 (29%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (16%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOblique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (2.6%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (4.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (12%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eACA Axis group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo astigmatism\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (3.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (5.2%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (8.0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWTR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e50 (65%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78 (67%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16 (64%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eATR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (30%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 (26%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3 (12%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOblique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (1.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 (1.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 (16%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eA hospital-based cross-sectional study aimed to determine the profile of astigmatism (refractive, anterior corneal and ocular residual) in a pediatric population with idiopathic congenital nystagmus. In this study, 71.6% of the ICN children were refractive astigmatism (RA) that was, similar to the study done in idiopathic congenital nystagmus population (65.37%)[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] and the normal population (13%)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], 26.76%[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. ACA was the most common type of astigmatism, at 76%, which is comparable to the myopic population (85%) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], but it was higher than those reported in the normal population (36.9%)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. However, the prevalence of ORA was (62%), which was greater than a study conducted among myopic children (51.5%)[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and preschool children (44.2%) respectively[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].The prevalence of RA seems to be greater in patients with ICNs than in the normal population. Similarly, In this study the prevalence of ACA among ICN children was similar to myopic children but much higher than normal population [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. However, the prevalence of ORA is higher among children with ICN than the children with myopia.The reason could be the higher prevalence of astigmatism among ICN than normal population because the children with ICN shows higher and more diverse refractive anomalies because of early foveal motor instability and associated ocular pathway abnormalities which disturb the emmetropization and produce axial and corneal asymmetries [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong the classifications of meridional astigmatism of the RA, compound hypermetropic astigmatism (33%) was frequently observed following compound myopic astigmatism (26.59%), whereas the reverse condition was observed among ICNs, in which compound myopic astigmatism was the most common type (30.72%), followed by compound hypermetropic astigmatism (27%)[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. This may be because the current study included a pediatric population (2\u0026ndash;18 years), whereas the study of Frencia et al. included ICN patients in the age range of 2\u0026ndash;69 years.\u003c/p\u003e \u003cp\u003eThe current study has median value with prevalence of RA, ACA, and ORA are 1.5D(71.6%), 1.5D(76.1%), 1D (62%) whereas a study conducted at Nanjing among preschool children their median value and prevalence was was 0.25D(14.2%), 1D(56.1%), 1(44.2%) respectively[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. This means that children with ICN have higher magnitude of RA, ACA compared with non nystagmus children but interestingly the median of ORA is similar. Prevalence of higher corneal astigmatism may be due to the frequent mechanical interaction between eyelid and cornea occurring due to nystagmoid movement [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The RA was predominantly moderate grade (37.2%), the ACA was low grade (33.9%), and the ORA was negligible (37.6%), which matched the previously documented patterns [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. On the basis of the limits of the axis WTR, ATR, and oblique, WTR was predominant in the ACA (66%) and RA (50.5%), but in the ORA, it was predominant in the ATR (49.1%), which also matched with preschool and myopic children[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. This finding indicates a greater dominance of WTR in the cornea, which seems to play a major role in overall refractive astigmatism in ICNs, similar to findings noted among the infantile nystagmus syndrome population. ORA displayed greater dominance of the ATR in approximately half of the total participants, which opposed the ACA. Thus, this study suggests that a compensatory mechanism, most likely from the crystalline lens, can develop. Therefore, ATR can be partially neutralized by WTR astigmatism of the anterior cornea. The magnitude of the ACA and ORA has a moderate positive correlation (r\u0026thinsp;=\u0026thinsp;0.324), which further supports that the internal compensatory response aligns with the findings of studies on the relationship between corneal and residual astigmatism[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] .\u003c/p\u003e \u003cp\u003eThe magnitude of astigmatism among age groups did not significantly differ (P\u0026thinsp;\u0026gt;\u0026thinsp;0.005). However, the axis was significantly different among the different age groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.005). This study revealed a shift in the orientation of the axis with age, i.e., a decrease in the WTR RA with age (p\u0026thinsp;=\u0026thinsp;0.004), and the oblique axis of the ACA increased with age, but there was no difference in the ORA particularly among the astigmatism classified based on the orientation of the axis with the age.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eChildren with idiopathic congenital nystagmus presented with high astigmatism involving refractive, anterior corneal and ocular residual astigmatism. WTR astigmatism was predominately presented on refractive and corneal astigmatism whereas ATR was predominance in ORA. Magnitude of astigmatism was remained stable in different age group but the astigmatic axis was statistically significant in age-related shift. So, comprehensive assessment including ACA and ORA is important to accurately diagnose the astigmatic profile and optimize long term clinical management in children with Idiopathic congenital nystagmus.\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStrength and limitation\u003c/h2\u003e \u003cp\u003eTo the best of our knowledge, this study is novel in reporting the distribution of anterior corneal astigmatism and ocular residual astigmatism in children with nystagmus using vector analysis. Thus, this study provides a better understanding of the underlying mechanisms of astigmatic characteristics than studies that focus solely on refractive error. This Study provides a comprehensive and precise profile of the astigmatic component of a specific clinical population (ICN) of the pediatric age group. An age-stratified approach helped to evaluate the developmental trend of the change of power and axis. However, the lack of a control group, hospital-based sampling, cross sectional study design may limit the generality of the study. This study included only anterior corneal astigmatism, so the contribution of the posterior cornea to total astigmatism was unknown. Therefore, advanced imaging, such as Schiempflug tomography, can help classify posterior corneal and lenticular astigmatism. Furthermore, investigating the impact of astigmatism on quality of life can be done.\u003c/p\u003e \u003c/div\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eICN\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIdiopathic congenital nystagmus\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eRA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eRefractive astigmatism\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eACA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAnterior corneal astigmatism\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eORA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eOcular residual astigmatism\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eWTR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eWith the rule\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eATR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAgainst the rule IQR:Inter-quartile range\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eStandard deviation.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u0026nbsp;\u003c/strong\u003eEthical clearance was obtained from the Institutional Review Committee of Lumbini Eye Institute and Research Center (Reference No. 023/018/19). The research was conducted in accordance with tenets of Declaration of Helsinki. The written informed and verbal consent was taken from the parents before enrollment in the study. For children age 16-18 years written informed consent was also taken from themselves.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e: \u0026nbsp; Not applicable\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e The datasets used during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no competing interest\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e: No financial disclosure\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization: \u0026nbsp; Dikshya Khadka, Romans Chaudhary, Hari Thapa\u003c/p\u003e\n\u003cp\u003eData collection: \u0026nbsp; Dikshya Khadka, Swarswati Khadka\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eFormal analysis: \u0026nbsp; Dikshya Khadka, Hari Prasad Upadhyay\u003c/p\u003e\n\u003cp\u003eInvestigation: Dikshya Khadka \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMethodology: Dikshya Khadka, Hari Thapa\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSupervision: Hari Thapa, Swaraswati Khadka\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWriting – original draft: Dikshya Khadka\u003c/p\u003e\n\u003cp\u003eWriting – review \u0026amp; editing: \u0026nbsp;Dikshya Khadka, Romans Chaudhary, Hari Prasad Upadhyay, Hari Thapa\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAuthors would like to express our sincere gratitude to all the participants for their valuable time and contribution to this research. Authors are also thankful to the Lumbini Eye Institute and Research Center (LEIRC), Nepal for granting ethical approval and for their continuous support and cooperation throughout the study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eJethani J, Prakash K, Vijayalakshmi P, Parija S. Changes in astigmatism in children with congenital nystagmus. Graefes Arch Clin Exp Ophthalmol. 2006;244(8):938\u0026ndash;43. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00417-005-0157-6\u003c/span\u003e\u003cspan address=\"10.1007/s00417-005-0157-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2005 Dec 16. PMID: 16362319.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePapageorgiou E, Asproudis I, Maconachie G, Tsironi EE, Gottlob I. The treatment of amblyopia: current practice and emerging trends. 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Optom Vis Sci Off Publ Am Acad Optom. 1997 June;74(6):367\u0026ndash;75.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Y, Li L, Tang XL, Guo GL, Chen MW, Cha LL et al. Characteristics of astigmatism in school-age children aged 5 to 13 years in northeast Sichuan: a cross-sectional school-based study. Transl Pediatr [Internet]. 2024 July 31 [cited 2025 Dec 7];13(7):1130\u0026ndash;40. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://pmc.ncbi.nlm.nih.gov/articles/PMC11319998/\u003c/span\u003e\u003cspan address=\"https://pmc.ncbi.nlm.nih.gov/articles/PMC11319998/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShah JR. A Review of Astigmatism - A Refractive Error correctable by Cylindrical glasses. J Drug Deliv Ther [Internet]. 2015 Mar 15 [cited 2025 Dec 9];5(2):29\u0026ndash;36. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://jddtonline.info/index.php/jddt/article/view/1073\u003c/span\u003e\u003cspan address=\"http://jddtonline.info/index.php/jddt/article/view/1073\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\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":"Refractive astigmatism, Anterior corneal astigmatism, Ocular residual astigmatism, Idiopathic congenital nystagmus","lastPublishedDoi":"10.21203/rs.3.rs-8472010/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8472010/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eIdiopathic nystagmus is a developmental oculomotor dysfunction. Individuals with ICN showed a higher rate of astigmatism compared to typically developing children. The aim of the study was to determine the distributions of refractive, corneal, and ocular residual astigmatism in children with idiopathic congenital nystagmus (ICN).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eRefractive astigmatism (RA) was obtained from objective cycloplegic refraction. Anterior corneal astigmatism (ACA)was determined by a hand-held keratometer. Thibos vector analysis was used to calculate ocular residual astigmatism(ORA). All the patients were divided into the following groups: preschool (2\u0026ndash;4 years), school-age (5\u0026ndash;12 years) and adolescents (13\u0026ndash;18 years) years.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eA total of 218 patients, 149 (68.3%), were male, and 69 (31.7%) were female. The mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD age of patients was 7.29\u0026thinsp;\u0026plusmn;\u0026thinsp;3.96 years (range 2\u0026ndash;18years). The overall prevalence and median value of (RA) was 156 (71.6%) CI (65\u0026ndash;78), 1D that of ACA was 166 (76.1%) CI (70\u0026ndash;81), 1.5D and that of ORA was 136 (62.4%) CI (56\u0026ndash;68),1D respectively. In terms of magnitude, the prevalence of RA was moderate 81 (37.2% ), that of ACA was low 74 (33.9%), and that of ORA was negligible 82 (37.6%). WTR is highly prevalent in RA 110 (50.5%) and ACA 58 (66.1%) whereas ATR 107 (49.1%) is commonly observed among ORA. There was a statistically significant change in axis with age (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) but there was a moderate positive correlation between the magnitude of the RA and the ACA (r\u0026thinsp;=\u0026thinsp;0.416, p\u0026thinsp;=\u0026thinsp;0.01).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eChildren with idiopathic congenital nystagmus had high prevalence of astigmatism involving refractive, anterior corneal and ocular residual astigmatism. WTR astigmatism was predominately presented on refractive and corneal astigmatism whereas ATR was predominance in ORA. So, comprehensive assessment including ACA and ORA is important to accurately diagnose the astigmatic profile and optimize long term clinical management in children with Idiopathic congenital nystagmus.\u003c/p\u003e","manuscriptTitle":"Distribution of Refractive, Anterior Corneal and Ocular Residual Astigmatism in Children with Idiopathic Congenital Nystagmus - A Cross-Sectional study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-20 11:27:06","doi":"10.21203/rs.3.rs-8472010/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":"0da72ba8-815e-415b-88bd-8dec40463333","owner":[],"postedDate":"January 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-02T05:55:23+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-20 11:27:06","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8472010","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8472010","identity":"rs-8472010","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}