Changes of Choroidal Thickness Varied Due to Different Lunch Break Posture and Refractive

Changes of Choroidal Thickness Varied Due to Different Lunch Break Posture and Refractive | 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 Article Changes of Choroidal Thickness Varied Due to Different Lunch Break Posture and Refractive Guangyao Ran, Zhiwei Luo, Qlinglin Xu, Yuangfang Yang, Wen Longbo, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4652335/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 The choroid is crucial in myopia prevention and control research. This study aimed to investigate the effects of different lunch break postures and refractive errors on choroidal thickness (CT) and choroidal vascular volume (CVV). Methods Healthy adult participants underwent a 45-minute lunch break in three different postures on consecutive days: lying lunch break, sitting head-on-arms lunch break, and sitting no lunch break. SS-OCTA measured CT and CVV in the macula before and after each lunch break. Changes in CT were also evaluated across different refractive errors. Results Among 40 adults (80 eyes), the average CT change was 11.62µm for lying lunch break, significantly higher than sitting head-on-arms lunch break (2.60µm) and sitting no lunch break (1.39µm) (both p < 0.0001). Average CVV changes were 8.5µm³ for lying lunch break, 1.9µm³ for sitting head-on-arms lunch break, and 1.3µm³ for sitting no lunch break. CT changes strongly correlated with CVV changes (F1,2158 = 306.1, p < 0.0001). During sitting head-on-arms lunch break, CT decreased by 6.00 ± 14.17 µm in the emmetropia and low hyperopia group, significantly different from other groups (all p < 0.0001). Conclusions Lying down during lunch breaks is most conducive to choroidal thickening, driven by increased CVV. Sitting head-on-arms may lead to choroidal thinning in people with emmetropia or low hyperopia. When considering the development of myopia in children and adolescents, it is suggested that LLB may serve as a protective factor while sitting head-on-arms lunch break may act as a risk factor. Health sciences/Health occupations Health sciences/Medical research choroidal thickness choroidal vascular volume lunch break myopia Figures Figure 1 Figure 2 Figure 3 Figure 4 Background Based on the 2022 population data released by China's National Bureau of Statistics, approximately 256.15 million children and adolescents reside in China, a significant portion of whom are primary and secondary school students requiring lunch breaks during school hours. According to the China Disease Control, the projected prevalence of myopia among young children in China is expected to reach 51.9% by the year 2022. Nevertheless, contemporary studies on lunch breaks primarily emphasize the management of stress levels and the restoration of mental well-being 1 , 2 , there is a paucity of research in the field of ophthalmology regarding the impact of lunch breaks on ocular structure and function. Myopia is a significant global public health issue, with the choroid playing a crucial role in its pathogenesis 3 , 4 . The choroid, a vital anatomical structure within the human eye, serves as the primary source of blood supply to the outer retina 5 – 7 . Numerous studies have indicated a correlation between sleep patterns and the onset of myopia, with the impact of sleep on the choroid potentially serving as a contributing factor 8 – 12 .The choroid demonstrates a reduced thickness in eyes afflicted with myopia when juxtaposed with eyes afflicted with astigmatism and hyperopia 13 .This has prompted several studies to propose that choroidal thickness could serve as an indicator of myopia progression, although this correlation has not been definitively established through quantitative analysis. Therefore, thickening of the choroid may potentially delay the onset of myopia, even if such thickening is only temporary. 14 , 15 . Hence, it is hypothesized that variations in lunch break postures could potentially impact choroidal thickness and blood perfusion, potentially influencing ocular development over time. Limited research of this nature has been conducted due to technological limitations. Historically, OCT or OCTA scanning frequencies were typically limited to thousands or tens of thousands of times per second, with measurement ranges typically confined to within 3mm of the macular center. The measurement principle typically relies on image recognition rather than blood flow signals, with Swept-source Optical Coherence Tomography Angiography (SS-OCTA) offering a more precise assessment of blood flow in the retina and choroid. Increased scanning frequency in OCTA results in higher scanning speeds and reduced errors. Our research aims to utilize SS-OCTA scanning at a frequency of 200,000 scans per second to assess a 6 millimeters range of macular diameter and various lunch break modes following an analysis of choroidal and blood flow alterations. This approach seeks to provide a more precise depiction of choroidal conditions and investigate the influence of different nap modes on the choroid. Materials And Methods Study design and participants This observational study received approval from the Ethics Committee of Changsha Aier Eye Hospital (ID:2023KYPJ018) and followed the principles outlined in the Declaration of Helsinki. Prior to participating in the study, all subjects provided written informed consent. The study's inclusion criteria comprised individuals aged 18 years or older, individuals accustomed to taking lunch breaks, those with intraocular pressure levels between 10–21 mmHg, and individuals with best-corrected visual acuity (BCVA) of 0.0 logarithm of the minimum angle of resolution or more (Snellen equivalent, 1.0 or 20/20) in either eye. Exclusion criteria encompassed individuals with a history of systemic diseases such as diabetes, hypertension, and hyperthyroidism, as well as those with a history of ophthalmic disease or surgery. Prior to the experiment, all participants were instructed to abstain from alcohol and caffeine for 3 days and to refrain from consuming any food or beverages for at least 30 minutes. Prior to the commencement of the study, all participants underwent a thorough baseline ophthalmologic assessment, which included evaluations of visual acuity, slit lamp examination, intraocular pressure (IOP) measurement, refraction, and axial length (AL) measurements. Subsequently, each participant was assessed for IOP, blood pressure (BP), choroidal thickness (CT), and choroidal vascular volume (CVV) both before and after the daily lunch break. Specific settings and environment for lunch breaks As shown in Fig. 1 , lunch break modes were classified into three categories: lying lunch break (LLB), sitting head-on-arms lunch break (SLB), and sitting no lunch break (NLB), with all participants mandated to partake in each of the specified modes. Finished the completion of all examinations, the subjects were re-categorized according to their spherical equivalent results following subjective refraction, encompassing emmetropia and low hyperopia (0D ~ + 3.0D), low myopia (-3.0D~-0.25D), moderate myopia (-6.0D-3.25D), and high myopia (≤ -6.0D). The environmental parameters and contextual factors for the lunch break were as follows: the ambient temperature was measured at around 26°C, the surrounding light intensity was below 10 lux, participants were directed to take a 45-minute lunch break between the hours of 13:00 and 14:00 for three consecutive days, with each day presenting a unique mode. On the initial day, all participants were directed to engage in the task of LLB. On the following day, all participants maintained a seated position with their hands resting on the table and their heads supported by their arms, a posture commonly referred to as SLB. On the third day of the experiment, all participants maintained NLB and were provided with the opportunity to engage in leisure activities such as using computers and smartphones, consistent with their typical behavior outside of the research setting. Instrument information and related parameters IOP was evaluated by noncontact tonometry (Canon TX-20, Tokyo, Japan). Corneal power and AL were measured using the IOL Master 700 (Carl Zeiss Meditec AG, Jena, Germany). Scanning-source optical coherence tomography angiography (SS-OCTA, VG200D; SVision Imaging, Henan, China) was used to detect CT and CVV based on EDTRS 16 ring 9 orientation as shown in Fig. 2 . SS-OCTA fundus images were obtained through the acquisition of a single line consisting of 512 horizontal B-scans in a raster scanning pattern encompassing a 6x6mm 2 area centered on the macula. Each B-scan included 512 individual repetitions of the average A-scan repeated 4 times. The CT and CVV values utilized in this research were aggregated within the Early Treatment Diabetic Retinopathy Study (EDTRS) ring. All evaluations were conducted by a consistent operator. Participants underwent measurements of systolic blood pressure (SBP) and diastolic blood pressure (DBP), from which mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP) were derived using specified equations 17 : MAP = \(\frac{1}{3}\times SBP+\frac{2}{3}\times DBP\) MOPP = \(\frac{2}{3}\times MAP-IOP\) Statistical Analysis All statistical analyses strictly followed a prespecified statistical analysis plan. Data was collected for each subject before and after the lunch break were averaged, including CT, CVV, IOP, MOPP. We conduct a statistical analysis on parameter measurements taken both before and after a lunch break utilizing a paired sample t-test. Repeated measures analysis of variance (ANOVA) was conducted to examine significant changes in CT、CVV、IOP and MOPP associated with various lunch break patterns. Simple linear regression was utilized to the relationship between changes in CT and CVV. Additionally, one-way ANOVA was employed to compare subgroups with different refractive error at the same lunch break pattern. All statistical analyses were performed using GraphPad Prism 9 software and p < 0.05 was considered significant. Results A total of 40 participants, with ages ranging from 19 to 34 years (median age 22 years) and comprising 19 males(47.5%) and 21 females(52.5%), were categorized into four groups based on their spherical equivalent refraction(SER) following subjective optometry. Situation of each SER group: orthoptic and low hyperopia group (range 0D to +2.125D, median SER 0D), low myopia group (range -2.75D to -0.5D, median SER -1.875D), moderate myopia group (range -5.125D to -3.125D, median SER -4.125D), and high myopia group (range -10.125D to -6.00D, median SER -6.75D). Effect of different lunch breaks on each parameter and correlation results Table 1 displays the baseline mean values of CT, CVV, IOP, and MOPP before the lunch break at LLB, which were measured at 310.96 ± 90.00μm, 366.4 ± 243.4μm 3 , 16.26 ± 2.62mm Hg, and 38.18 ± 5.56mm Hg, respectively. After LLB, the mean values of these biological measurement indicators were observed to be 322.59 ± 89.80 μ m, 374.9 ± 246.3μm 3 , 16.28 ± 3.19mmHg, and 35.86 ± 5.44mmHg. Statistical analysis revealed significant increase d in the mean values of CT, CVV, and significant decrease d in MOPP before and after LLB (paired t-test, all p < 0.05). Before SLB, the baseline mean values of CT, CVV, IOP and MOPP were measured as follows: 311.29 ± 90.99 μm, 365.3 ± 243.6μm 3 , 15.83 ± 2.63 mmHg, and 37.05 ± 4.73 mmHg, respectively. After SLB, the mean values of these parameters were recorded as 313.89 ± 90.99 μm, 367.2 ± 242.7μm 3 , 16.68 ± 3.64 mmHg, and 34.09 ± 6.17 mmHg. Statistical analysis revealed significant increase d in the mean values of CT, CVV, IOP, and significant decrease d in MOPP before and after the lunch break (paired t-test, all p < 0.05). Before NLB, the mean values of CT, CVV, IOP, and MOPP were 313.89 ± 89.83 μm, 368.2 ± 245.8μm 3 , 16.11 ± 2.82 mmHg, and 37.52 ± 5.72 mmHg, respectively. Following the lunch break, the average values of these biological measurement indicators were 315.27 ± 89.51 μm, 369.5 ± 246.3μm 3 , 15.94 ± 3.16 mmHg, and 37.44 ± 6.50 mmHg. A statistically significant increased was observed in the average values of CT and CVV before and after the lunch break (paired t-test, both p <0.05). Significant alterations in CT, CVV, IOP and MOPP were noted across various lunch break schedules (repeated measures ANOVA: F2,2157 = 208.00, p < 0.0001 for CT; F2,2157 = 27.43, p <0.0001 for CVV; F2,237 = 5.40, p = 0.0051 for IOP; F2,237 =9.22, p = 0.0001 for MOPP). The mean choroidal thickening in the LLB, SLB, and NLB groups was determined to be 11.62 ± 10.39μm, 2.60 ± 11.46μm, and 1.39 ± 9.23μm, respectively. A statistically significant difference was observed in the choroidal thickening between the LLB group and the other two lunch break mode groups (pair-wise comparison: both p < 0.0001). The CVV exhibited increases of 8.5 ± 22.9μm3, 1.9 ± 20.3 μm3, and 1.3 ± 17.9μm3 in the LLB, SLB, and NLB groups, respectively. The data presented in Figure 3 demonstrates a significant correlation between alterations in CT and variations in CVV (simple linear regression analysis: F1,2158 = 306.1, p < 0.0001). Effect of different lunch breaks on the choroid of each refractive error group According to the data presented in Figure 4 a, following LLB, the thickness of the retina increased by 8.06 ± 14.77μm in the emmetropia and low hyperopia group, 10.25 ± 8.13μm in the low myopia group, 14.00 ± 12.20μm in the moderate myopia group, and 12.26 ± 5.00μm in the high myopia group. There were significant differences in choroidal thickness between the emmetropia and low hyperopia group compared to the moderate myopia group, the low myopia group compared to the moderate myopia group, and the emmetropia and low hyperopia group compared to the high myopia group (Respectively: p 1< 0.0001, p 2=0.0002, p 3=0.0205). Following the administration of SLB, a notable decline in the average magnitude of the overall alteration in the choroid of both eyes was noted in the emmetropia and low hyperopia group, measuring -6.00 ± 14.17 μm in Figure 4 b. This discrepancy was found to be statistically significant when compared to all other groups (all p < 0.0001). Nevertheless, the group with moderate myopia exhibited the highest mean value of choroidal thickening at 6.27 ± 13.20 μm, followed by the high myopia group at 5.14 ± 4.76 μm, and the low myopia group at 0.70 ± 9.05 μm. The disparities in significance between the low myopia group and the moderate myopia group, as well as between the low myopia group and the high myopia group, were equally pronounced (Respectively : p 1< 0.0001, p 2 =0.008). Following the administration of NLB, choroidal changes were found to be statistically insignificant across all four groups, as indicated by the mean values of changes and the lack of significant differences between groups, as illustrated in Figure 4c (all p ＞0.05). Discussion The choroid plays a role in the regulation of ocular growth, which may have significant implications for the pathogenesis and management of myopia, particularly in the adolescent population 5 , 18 – 20 . OCT has been frequently utilized in prior research to assess choroidal thickness beneath the macula, with certain measurements being obtained through manual means. Previous studies have calculated CVV values using OCT measurement results, however, this approach overlooked the potential impact of the extracellular matrix 21 , 22 . This study employed SS-OCTA utilizing blood flow signals with a scanning frequency of z200,000 times per second to quantify the actual CCV and CT within a 6 x 6mm area. The results of our study indicate that LLB resulted in a mean choroidal thickening of 11.62µm, which was significantly higher than the 2.60µm and 1.39µm thickening observed in the SLB and NLB groups, respectively. The choroid is characterized by having one of the highest blood flow rates among the body's tissues, with medium and large blood vessels playing a significant role in this vascular network 18 , 23 , CVV exhibited a similar trend to CT, with LLB resulting in an increase of 0.0085 mm 3 , SLB increasing by 0.0019 mm 3 , and NLB increasing by 0.0013 mm 3 . This further supports the assertion that alterations in CVV play a significant role in influencing changes in CT. Prior research suggests that sleep is intricately linked to the neurobiological regulation of histamine, dopamine, norepinephrine, and the cholinergic system, all of which play a role in vasoconstriction and diastole, ultimately affecting blood flow in the vessels. 24 – 28 . It can be inferred that LLB is more advantageous in restoring choroidal blood supply under neurohumoral regulation, resulting in an elevation of CVV and subsequent choroidal thickening. Conversely, SLB did not induce substantial choroidal thickening, potentially attributed to the mechanical pressure exerted by the arm on the periocular region, impeding adequate blood supply to the compressed eye. This mechanical pressure caused both an increase in IOP and a decrease in MOPP, further decreasing the blood supply to the choroid and leading to choroidal thinning 29 – 31 . The thinning of the choroid from noon to afternoon, attributed to rhythmic changes in the choroid and prolonged eye use, appears to be the primary factor contributing to the lack of significant changes in CT and CVV in eyes 32 . The IOP exhibited a decrease in NLB and remained unchanged in LLB, a phenomenon that could potentially be attributed to variations in body positioning. Malihi et al. 33 highlighted in their research that individuals experience lower ocular pressure while seated compared to when in a supine position. Our findings demonstrate that as the negative degree of refractive error increases, choroidal thickening becomes more pronounced with LLB and SLB. Of note, individuals in the emmetropia and low hyperopia group exhibited a trend of choroidal thinning during SLB, a phenomenon not previously documented in existing literature. SLB may exert mechanical pressure on the eye due to the positioning of the head on the arms, which is a significant contributing factor to impaired choroidal filling. The choroidal vascular system is supported by fibroblasts that create a scaffold rich in collagen and elastic elements 34 , 35 . In the thicker choroid, a higher concentration of fibroblasts results in a greater elastic force, leading to the formation of pronounced gaps; conversely, the thinner choroid contains a lower fibroblast count, resulting in reduced elasticity 36 . Our hypothesis posits that the choroid's thickness correlates with its ability to withstand mechanical stress, resulting in more pronounced thinning. This is supported by the absence of substantial choroidal thickening in the low myopia group with SLB. During NLB, there was no statistically significant alteration in choroidal thickness among the various refractive error groups, suggesting that the act of napping may indeed promote choroidal thickening. The choroid undergoes rhythmic fluctuations and experiences a thinning process from midday to late afternoon 37 – 39 . The results of our study indicate that LLB promotes choroidal thickening at midday, and while this thickening may be temporary, Wallman et al. 14 observed in their research that transient thickening of the choroid can also impede the growth of axial length. This suggests that varying lunch break modes may have implications for eye development. However, it is important to note the limitations of our study, which was conducted on adult participants. Future research involving child and adolescent populations is necessary to further elucidate the scientific findings. Nonetheless, we advocate for the adoption of LLB, particularly for individuals who have not yet developed myopia. Conclusion In summary, lying lunch break is more beneficial for choroidal thickening compared to other postures. Increased CVV is the primary factor contributing to this thickening. Sitting head-on-arms is associated with choroidal thinning in emmetropia and low hyperopia, while moderate myopia shows the most significant CT increase. Incorporating lying lunch break may serve as a potential protective measure against myopia, whereas Sitting head-on-arms lunch breaks may be a risk factor for the development of myopia in children and adolescents. Abbreviations CT choroidal thickness CVV choroidal vascular volume IOP intraocular pressure MOPP mean ocular perfusion pressure LLB lying lunch break SLB sitting head-on-arms lunch break NLB sitting no lunch break Declarations Acknowledgements We thank Jiangdong Hao(Aier Academy of Ophthalmology, Central South University) and Xiaoyun(Aier Institute of Optometry and Vision Science) for his technical assistance in this study. Authors ’ contributions GYR and XNL contributed to the concept of the study. ZWL, QLX, YFY, ZKY,LBW and LZ acquired and analyzed the data. GYR performed software analysis. ZWL, YFY helped with the interpretation of the data. GYR drafted the manuscript. QLX, YFY, ZKY and LBW reviewed and the manuscript. XNL supervised the study. All authors read and approved the fnal manuscript. Funding Hunan Province Optometry Engineering and Technology Research Center(2020TP2003) Hunan Province International Cooperation Base for Optometry Science and Technology (2020CB1002) Hubei Key R&D Program(2020BCB013) Hunan Provincial Natural Foundation（2023JJ70031） Availability of data and materials The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Ethics approval and consent to participate This observational study received approval from the Ethics Committee of Changsha Aier Eye Hospital (ID:2023KYPJ018) and followed the principles outlined in the Declaration of Helsinki. Prior to participating in the study, all subjects provided written informed consent. Consent for publication Not Applicable. Competing interests The authors declare that they have no competing interests. References Krajewski, J., Wieland, R. & Sauerland, M. Regulating strain states by using the recovery potential of lunch breaks. J Occup Health Psychol 15, 131–139 (2010). Bennett, A. A., Gabriel, A. S. & Calderwood, C. Examining the interplay of micro-break durations and activities for employee recovery: A mixed-methods investigation. J Occup Health Psychol 25, 126–142 (2020). Holden, B. A. et al. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology 123, 1036–1042 (2016). Peng, W., Zhang, Z., Wang, F., Sun, S. & Sun, Y. Association of educational environment with the prevalence of myopia: a cross-sectional study in central China. Front Public Health 11, 1188198 (2023). Nickla, D. L. & Wallman, J. The multifunctional choroid. Prog Retin Eye Res 29, 144–168 (2010). Liu, R. et al. Effect of Choroidal Vessel Density on the Ellipsoid Zone and Visual Function in Retinitis Pigmentosa Using Optical Coherence Tomography Angiography. Invest Ophthalmol Vis Sci 60, 4328–4335 (2019). Linsenmeier, R. A., Goldstick, T. K., Blum, R. S. & Enroth-Cugell, C. Estimation of retinal oxygen transients from measurements made in the vitreous humor. Exp Eye Res 32, 369–379 (1981). Wei, S.-F. et al. Sleep Duration, Bedtime, and Myopia Progression in a 4-Year Follow-up of Chinese Children: The Anyang Childhood Eye Study. Invest Ophthalmol Vis Sci 61, 37 (2020). Lee, S. S. Y., Nilagiri, V. K. & Mackey, D. A. Sleep and eye disease: A review. Clin Exp Ophthalmol 50, 334–344 (2022). Scuderi, G. et al. Short-Term Effects of Dark Chocolate on Retinal and Choriocapillaris Perfusion in Young, Healthy Subjects Using Optical Coherence Tomography Angiography. Nutrients 12, 664 (2020). Ostrin, L. A., Jnawali, A., Carkeet, A. & Patel, N. B. Twenty-four hour ocular and systemic diurnal rhythms in children. Ophthalmic Physiol Opt 39, 358–369 (2019). Liu, X. N. et al. Sleeping late is a risk factor for myopia development amongst school-aged children in China. Sci Rep 10, 17194 (2020). Prousali, E., Dastiridou, A., Ziakas, N., Androudi, S. & Mataftsi, A. Choroidal thickness and ocular growth in childhood. Surv Ophthalmol 66, 261–275 (2021). Zhu, X., Park, T. W., Winawer, J. & Wallman, J. In a matter of minutes, the eye can know which way to grow. Invest Ophthalmol Vis Sci 46, 2238–2241 (2005). Nickla, D. L. Ocular diurnal rhythms and eye growth regulation: where we are 50 years after Lauber. Exp Eye Res 114, 25–34 (2013). Grading diabetic retinopathy from stereoscopic color fundus photographs–an extension of the modified Airlie House classification. ETDRS report number 10. Early Treatment Diabetic Retinopathy Study Research Group. Ophthalmology 98, 786–806 (1991). Van Keer, K., Breda, J. B., Pinto, L. A., Stalmans, I. & Vandewalle, E. Estimating Mean Ocular Perfusion Pressure Using Mean Arterial Pressure and Intraocular Pressure. Invest Ophthalmol Vis Sci 57, 2260 (2016). Ostrin, L. A. et al. IMI-The Dynamic Choroid: New Insights, Challenges, and Potential Significance for Human Myopia. Invest Ophthalmol Vis Sci 64, 4 (2023). Ss, L. et al. Choroidal Thickening During Young Adulthood and Baseline Choroidal Thickness Predicts Refractive Error Change. Investigative ophthalmology & visual science 63, (2022). Tian, F. et al. Choroidal and Retinal Thickness and Axial Eye Elongation in Chinese Junior Students. Invest Ophthalmol Vis Sci 62, 26 (2021). Wang, J. C. et al. Diabetic Choroidopathy: Choroidal Vascular Density and Volume in Diabetic Retinopathy With Swept-Source Optical Coherence Tomography. Am J Ophthalmol 184, 75–83 (2017). Laíns, I. et al. Choroidal Changes Associated With Subretinal Drusenoid Deposits in Age-related Macular Degeneration Using Swept-source Optical Coherence Tomography. Am J Ophthalmol 180, 55–63 (2017). Alm, A. & Bill, A. Ocular and optic nerve blood flow at normal and increased intraocular pressures in monkeys (Macaca irus): a study with radioactively labelled microspheres including flow determinations in brain and some other tissues. Exp Eye Res 15, 15–29 (1973). Mesulam, M. M., Mufson, E. J., Wainer, B. H. & Levey, A. I. Central cholinergic pathways in the rat: an overview based on an alternative nomenclature (Ch1-Ch6). Neuroscience 10, 1185–1201 (1983). Hobson, J. A., McCarley, R. W. & Wyzinski, P. W. Sleep cycle oscillation: reciprocal discharge by two brainstem neuronal groups. Science 189, 55–58 (1975). Aston-Jones, G. & Bloom, F. E. Activity of norepinephrine-containing locus coeruleus neurons in behaving rats anticipates fluctuations in the sleep-waking cycle. J Neurosci 1, 876–886 (1981). Berridge, C. W., Page, M. E., Valentino, R. J. & Foote, S. L. Effects of locus coeruleus inactivation on electroencephalographic activity in neocortex and hippocampus. Neuroscience 55, 381–393 (1993). Siegel, J. M. & Boehmer, L. N. Narcolepsy and the hypocretin system–where motion meets emotion. Nat Clin Pract Neurol 2, 548–556 (2006). Read, S. A. et al. The short-term influence of elevated intraocular pressure on axial length. Ophthalmic Physiol Opt 31, 398–403 (2011). Petersen, L. G. et al. Gravitational effects on intraocular pressure and ocular perfusion pressure. J Appl Physiol (1985) 132, 24–35 (2022). Lee, T.-E., Yoo, C. & Kim, Y. Y. Effects of different sleeping postures on intraocular pressure and ocular perfusion pressure in healthy young subjects. Ophthalmology 120, 1565–1570 (2013). Aptel, F., Weinreb, R. N., Chiquet, C. & Mansouri, K. 24-h monitoring devices and nyctohemeral rhythms of intraocular pressure. Prog Retin Eye Res 55, 108–148 (2016). Malihi, M. & Sit, A. J. Effect of head and body position on intraocular pressure. Ophthalmology 119, 987–991 (2012). Gelman, S. et al. The presence and distribution of elastin in the posterior and retrobulbar regions of the mouse eye. Exp Eye Res 90, 210–215 (2010). Quigley, H. A., Dorman-Pease, M. E. & Brown, A. E. Quantitative study of collagen and elastin of the optic nerve head and sclera in human and experimental monkey glaucoma. Curr Eye Res 10, 877–888 (1991). Wildsoet, C. & Wallman, J. Choroidal and scleral mechanisms of compensation for spectacle lenses in chicks. Vision Res 35, 1175–1194 (1995). Nickla, D. L., Wildsoet, C. & Wallman, J. Visual influences on diurnal rhythms in ocular length and choroidal thickness in chick eyes. Exp Eye Res 66, 163–181 (1998). Nickla, D. L., Wildsoet, C. F. & Troilo, D. Diurnal rhythms in intraocular pressure, axial length, and choroidal thickness in a primate model of eye growth, the common marmoset. Invest Ophthalmol Vis Sci 43, 2519–2528 (2002). Stone, R. A. et al. Diurnal axial length fluctuations in human eyes. Invest Ophthalmol Vis Sci 45, 63–70 (2004). Table Table 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Table1.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-4652335","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":328526692,"identity":"e23a30f2-b701-4669-bebd-cf934faa3152","order_by":0,"name":"Guangyao Ran","email":"","orcid":"","institution":"Aier Academy of Ophthalmology, Central South University","correspondingAuthor":false,"prefix":"","firstName":"Guangyao","middleName":"","lastName":"Ran","suffix":""},{"id":328526693,"identity":"f18ea403-e859-4ab6-aa94-a56245cfa18b","order_by":1,"name":"Zhiwei Luo","email":"","orcid":"","institution":"Aier Institute of Optometry and Vision Science","correspondingAuthor":false,"prefix":"","firstName":"Zhiwei","middleName":"","lastName":"Luo","suffix":""},{"id":328526694,"identity":"0d6897e7-afe9-4725-9a9e-15b55e0f178e","order_by":2,"name":"Qlinglin Xu","email":"","orcid":"","institution":"Aier Institute of Optometry and Vision Science","correspondingAuthor":false,"prefix":"","firstName":"Qlinglin","middleName":"","lastName":"Xu","suffix":""},{"id":328526695,"identity":"b6d5fb21-a565-4cd2-8f5c-47bbef332169","order_by":3,"name":"Yuangfang Yang","email":"","orcid":"","institution":"Aier Academy of Ophthalmology, Central South University","correspondingAuthor":false,"prefix":"","firstName":"Yuangfang","middleName":"","lastName":"Yang","suffix":""},{"id":328526696,"identity":"8d682278-029e-484f-aa71-2e2d6db7fabe","order_by":4,"name":"Wen Longbo","email":"","orcid":"","institution":"Aier Institute of Optometry and Vision Science","correspondingAuthor":false,"prefix":"","firstName":"Wen","middleName":"","lastName":"Longbo","suffix":""},{"id":328526697,"identity":"c66ea2a8-a4dd-48e0-ab61-4fc40b65a3c0","order_by":5,"name":"Ling Zeng","email":"","orcid":"","institution":"Aier Institute of Optometry and Vision Science","correspondingAuthor":false,"prefix":"","firstName":"Ling","middleName":"","lastName":"Zeng","suffix":""},{"id":328526698,"identity":"207abcb5-9855-4cd9-8b59-fc7275547885","order_by":6,"name":"Zhikuan Yang","email":"","orcid":"","institution":"Aier Institute of Optometry and Vision Science","correspondingAuthor":false,"prefix":"","firstName":"Zhikuan","middleName":"","lastName":"Yang","suffix":""},{"id":328526699,"identity":"bde9d980-7496-487d-a02d-e07c457a03f6","order_by":7,"name":"Xiaoning Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIiWNgGAWjYBACPmYGhgNAmoeBgfkAQwKQZcBMQAsbQgtbApFaEEweAzBlQMhhbOw8hgd+VNyRMedf8/HDg4p78ubsvAc/MNTYRON2GFvCwZ4zz3gsZ7zdLJFwpthwZzNfsgTDsbTcBpxamA8c4G07zGNw4+wGicS2hAQDIFuCseEwHi2MDQf/grWcefwj8R9Yi/EP/FqYDxwG23K+h00isQGsxYyALWwJh2XOgGxhM7NIOJZguAGoBcjA7Rd+/jPGH99UHLY3OH/48c0fNQnyBufPGN/4UGODUwsCSCQgcRJwKEKz7wBRykbBKBgFo2AEAgDD+Vlwe/n5TQAAAABJRU5ErkJggg==","orcid":"","institution":"Aier Institute of Optometry and Vision Science","correspondingAuthor":true,"prefix":"","firstName":"Xiaoning","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2024-06-28 05:57:40","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4652335/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4652335/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":60943643,"identity":"964233c8-2dc3-4303-97dd-bd46739bb862","added_by":"auto","created_at":"2024-07-23 22:03:08","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":198246,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDiagram of the three lunch break postures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eAll subjects took a lying lunch break (LLB) on the first day and sitting head-on-arms lunch break (SLB) on the second day and sitting no lunch break (NLB) on the third day of three consecutive lunch breaks.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-4652335/v1/01b4393891a79a16caf5b4f0.png"},{"id":60944422,"identity":"96b13696-08c8-43e4-9eef-fe7cc0d93fb1","added_by":"auto","created_at":"2024-07-23 22:11:08","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1719580,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMeasurement of choroidal thickness and choroidal vascular volume based on EDTRS rings\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eA single measurement yields choroidal thickness values in μm in a circular area of the macula centered on the macular central sulcus with a diameter of 6 mm. EDTRS ring can be divided into 9 regions: CS, SI, TI, NI, II, SO, TO, NO, and IO. Nine values in a single measurement, the mean values of the 9 regions were used in this study.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-4652335/v1/8fbf29312610b18008991400.png"},{"id":60943644,"identity":"1f6e38b2-e358-4ea3-a177-fa974ea9a142","added_by":"auto","created_at":"2024-07-23 22:03:08","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":398128,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe correlation between the change in choroidal thickness and choroidal vascular volume\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eCorrelation analysis between CT and CVV was done based on single measurements of changes in nine regions within the EDTRS ring.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-4652335/v1/8855d1f0653e33c5e2caf14b.png"},{"id":60944421,"identity":"36ce7b22-4cb7-46a1-ab77-45cfd606d4d3","added_by":"auto","created_at":"2024-07-23 22:11:08","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":702413,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMean changes in choroidal thickness within different modalities of lunch breaks among refractive error groups\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLLB: Lying lunch break；\u003c/p\u003e\n\u003cp\u003eSLB : Sitting head-on-arms lunch break；\u003c/p\u003e\n\u003cp\u003eNLB: Sitting no lunch break.\u003c/p\u003e\n\u003cp\u003eOrthoptic and low hyperopia group (n=9 eyes), low myopia group (n=30 eyes), moderate myopia group (n=27 eyes), and high myopia group (n=14 eyes), which were categorized according to spherical equivalent degree.\u003c/p\u003e\n\u003cp\u003eANOVA was used to compare the variability of CT changes in LLB, SLB, and NLB with different refractive errors; * means p-value ＜ 0.05; ** means p-value l＜ 0.01; *** means p-value ＜ 0.001; **** means p-value ＜ 0.0001; \"ns\" means p-value \u0026gt; 0.05.\u003c/p\u003e","description":"","filename":"Figure4abc.png","url":"https://assets-eu.researchsquare.com/files/rs-4652335/v1/e263e8c50113fb9d48f4e7c8.png"},{"id":63573080,"identity":"fd03a5b9-c83a-4ba9-be2e-693b90a76e1c","added_by":"auto","created_at":"2024-08-29 18:18:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4183713,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4652335/v1/82f474d6-2d85-45ee-9601-03b0a59f0b43.pdf"},{"id":60945084,"identity":"4f9f9a8c-98a8-4857-990e-cebdef02ab98","added_by":"auto","created_at":"2024-07-23 22:19:08","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":182303,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-4652335/v1/71ab0fc789703329d93e3e58.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Changes of Choroidal Thickness Varied Due to Different Lunch Break Posture and Refractive","fulltext":[{"header":"Background","content":"\u003cp\u003eBased on the 2022 population data released by China's National Bureau of Statistics, approximately 256.15\u0026nbsp;million children and adolescents reside in China, a significant portion of whom are primary and secondary school students requiring lunch breaks during school hours. According to the China Disease Control, the projected prevalence of myopia among young children in China is expected to reach 51.9% by the year 2022. Nevertheless, contemporary studies on lunch breaks primarily emphasize the management of stress levels and the restoration of mental well-being\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, there is a paucity of research in the field of ophthalmology regarding the impact of lunch breaks on ocular structure and function.\u003c/p\u003e \u003cp\u003eMyopia is a significant global public health issue, with the choroid playing a crucial role in its pathogenesis\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. The choroid, a vital anatomical structure within the human eye, serves as the primary source of blood supply to the outer retina\u003csup\u003e\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. Numerous studies have indicated a correlation between sleep patterns and the onset of myopia, with the impact of sleep on the choroid potentially serving as a contributing factor\u003csup\u003e\u003cspan additionalcitationids=\"CR9 CR10 CR11\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.The choroid demonstrates a reduced thickness in eyes afflicted with myopia when juxtaposed with eyes afflicted with astigmatism and hyperopia\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e.This has prompted several studies to propose that choroidal thickness could serve as an indicator of myopia progression, although this correlation has not been definitively established through quantitative analysis. Therefore, thickening of the choroid may potentially delay the onset of myopia, even if such thickening is only temporary.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eHence, it is hypothesized that variations in lunch break postures could potentially impact choroidal thickness and blood perfusion, potentially influencing ocular development over time. Limited research of this nature has been conducted due to technological limitations. Historically, OCT or OCTA scanning frequencies were typically limited to thousands or tens of thousands of times per second, with measurement ranges typically confined to within 3mm of the macular center. The measurement principle typically relies on image recognition rather than blood flow signals, with Swept-source Optical Coherence Tomography Angiography (SS-OCTA) offering a more precise assessment of blood flow in the retina and choroid. Increased scanning frequency in OCTA results in higher scanning speeds and reduced errors. Our research aims to utilize SS-OCTA scanning at a frequency of 200,000 scans per second to assess a 6 millimeters range of macular diameter and various lunch break modes following an analysis of choroidal and blood flow alterations. This approach seeks to provide a more precise depiction of choroidal conditions and investigate the influence of different nap modes on the choroid.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eStudy design and participants\u003c/h2\u003e\n \u003cp\u003eThis observational study received approval from the Ethics Committee of Changsha Aier Eye Hospital (ID:2023KYPJ018) and followed the principles outlined in the Declaration of Helsinki. Prior to participating in the study, all subjects provided written informed consent.\u003c/p\u003e\n \u003cp\u003eThe study\u0026apos;s inclusion criteria comprised individuals aged 18 years or older, individuals accustomed to taking lunch breaks, those with intraocular pressure levels between 10\u0026ndash;21 mmHg, and individuals with best-corrected visual acuity (BCVA) of 0.0 logarithm of the minimum angle of resolution or more (Snellen equivalent, 1.0 or 20/20) in either eye. Exclusion criteria encompassed individuals with a history of systemic diseases such as diabetes, hypertension, and hyperthyroidism, as well as those with a history of ophthalmic disease or surgery. Prior to the experiment, all participants were instructed to abstain from alcohol and caffeine for 3 days and to refrain from consuming any food or beverages for at least 30 minutes.\u003c/p\u003e\n \u003cp\u003ePrior to the commencement of the study, all participants underwent a thorough baseline ophthalmologic assessment, which included evaluations of visual acuity, slit lamp examination, intraocular pressure (IOP) measurement, refraction, and axial length (AL) measurements. Subsequently, each participant was assessed for IOP, blood pressure (BP), choroidal thickness (CT), and choroidal vascular volume (CVV) both before and after the daily lunch break.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003eSpecific settings and environment for lunch breaks\u003c/h2\u003e\n \u003cp\u003eAs shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, lunch break modes were classified into three categories: lying lunch break (LLB), sitting head-on-arms lunch break (SLB), and sitting no lunch break (NLB), with all participants mandated to partake in each of the specified modes. Finished the completion of all examinations, the subjects were re-categorized according to their spherical equivalent results following subjective refraction, encompassing emmetropia and low hyperopia (0D\u0026thinsp;~\u0026thinsp;+\u0026thinsp;3.0D), low myopia (-3.0D~-0.25D), moderate myopia (-6.0D-3.25D), and high myopia (\u0026le; -6.0D). The environmental parameters and contextual factors for the lunch break were as follows: the ambient temperature was measured at around 26\u0026deg;C, the surrounding light intensity was below 10 lux, participants were directed to take a 45-minute lunch break between the hours of 13:00 and 14:00 for three consecutive days, with each day presenting a unique mode. On the initial day, all participants were directed to engage in the task of LLB. On the following day, all participants maintained a seated position with their hands resting on the table and their heads supported by their arms, a posture commonly referred to as SLB. On the third day of the experiment, all participants maintained NLB and were provided with the opportunity to engage in leisure activities such as using computers and smartphones, consistent with their typical behavior outside of the research setting.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003eInstrument information and related parameters\u003c/h2\u003e\n \u003cp\u003eIOP was evaluated by noncontact tonometry (Canon TX-20, Tokyo, Japan). Corneal power and AL were measured using the IOL Master 700 (Carl Zeiss Meditec AG, Jena, Germany). Scanning-source optical coherence tomography angiography (SS-OCTA, VG200D; SVision Imaging, Henan, China) was used to detect CT and CVV based on EDTRS\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e ring 9 orientation as shown in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. SS-OCTA fundus images were obtained through the acquisition of a single line consisting of 512 horizontal B-scans in a raster scanning pattern encompassing a 6x6mm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e area centered on the macula. Each B-scan included 512 individual repetitions of the average A-scan repeated 4 times. The CT and CVV values utilized in this research were aggregated within the Early Treatment Diabetic Retinopathy Study (EDTRS) ring. All evaluations were conducted by a consistent operator. Participants underwent measurements of systolic blood pressure (SBP) and diastolic blood pressure (DBP), from which mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP) were derived using specified equations\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e:\u003c/p\u003e\n\u003c/div\u003e\n\u003ch2 class=\"Heading\"\u003eMAP = \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\frac{1}{3}\\times SBP+\\frac{2}{3}\\times DBP\\)\u003c/span\u003e\u003c/span\u003e\u003c/h2\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eMOPP =\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\frac{2}{3}\\times MAP-IOP\\)\u003c/span\u003e\u003c/span\u003e\u003c/h2\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003eStatistical Analysis\u003c/h2\u003e\n \u003cp\u003eAll statistical analyses strictly followed a prespecified statistical analysis plan. Data was collected for each subject before and after the lunch break were averaged, including CT, CVV, IOP, MOPP. We conduct a statistical analysis on parameter measurements taken both before and after a lunch break utilizing a paired sample t-test. Repeated measures analysis of variance (ANOVA) was conducted to examine significant changes in CT、CVV、IOP and MOPP associated with various lunch break patterns. Simple linear regression was utilized to the relationship between changes in CT and CVV. Additionally, one-way ANOVA was employed to compare subgroups with different refractive error at the same lunch break pattern. All statistical analyses were performed using GraphPad Prism 9 software and \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered significant.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 40 participants, with ages ranging from 19 to 34 years (median age 22 years) and comprising 19 males(47.5%) and 21 females(52.5%), were categorized into four groups based on their spherical equivalent refraction(SER) following subjective optometry. Situation of each SER group: orthoptic and low hyperopia group (range 0D to +2.125D, median SER 0D), low myopia group (range -2.75D to -0.5D, median SER -1.875D), moderate myopia group (range -5.125D to -3.125D, median SER -4.125D), and high myopia group (range -10.125D to -6.00D, median SER -6.75D).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of different lunch breaks on each parameter and correlation results\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTable 1 displays the baseline mean values of CT, CVV, IOP, and MOPP before the lunch break at LLB, which were measured at 310.96 \u0026plusmn; 90.00\u0026mu;m, 366.4 \u0026plusmn; 243.4\u0026mu;m\u003csup\u003e3\u003c/sup\u003e, 16.26 \u0026plusmn; 2.62mm Hg, and 38.18 \u0026plusmn; 5.56mm Hg, respectively. After LLB, the mean values of these biological measurement indicators were observed to be 322.59 \u0026plusmn; 89.80 \u0026mu; m, 374.9 \u0026plusmn; 246.3\u0026mu;m\u003csup\u003e3\u003c/sup\u003e, 16.28 \u0026plusmn; 3.19mmHg, and 35.86 \u0026plusmn; 5.44mmHg. Statistical analysis revealed significant increase\u003cu\u003ed\u0026nbsp;\u003c/u\u003ein the mean values of CT, CVV, and significant decrease\u003cu\u003ed\u0026nbsp;\u003c/u\u003ein MOPP before and after LLB (paired t-test, all \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05). Before SLB, the baseline mean values of CT, CVV, IOP and MOPP were measured as follows: 311.29 \u0026plusmn; 90.99 \u0026mu;m, 365.3 \u0026plusmn; 243.6\u0026mu;m\u003csup\u003e3\u003c/sup\u003e, 15.83 \u0026plusmn; 2.63 mmHg, and 37.05 \u0026plusmn; 4.73 mmHg, respectively. After SLB, the mean values of these parameters were recorded as 313.89 \u0026plusmn; 90.99 \u0026mu;m, 367.2 \u0026plusmn; 242.7\u0026mu;m\u003csup\u003e3\u003c/sup\u003e, 16.68 \u0026plusmn; 3.64 mmHg, and 34.09 \u0026plusmn; 6.17 mmHg. Statistical analysis revealed significant increase\u003cu\u003ed\u0026nbsp;\u003c/u\u003ein the mean values of CT, CVV, IOP, and significant decrease\u003cu\u003ed\u0026nbsp;\u003c/u\u003ein MOPP before and after the lunch break (paired t-test, all \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.05). Before NLB, the mean values of CT, CVV, IOP, and MOPP were 313.89 \u0026plusmn; 89.83 \u0026mu;m, 368.2 \u0026plusmn; 245.8\u0026mu;m\u003csup\u003e3\u003c/sup\u003e, 16.11 \u0026plusmn; 2.82 mmHg, and 37.52 \u0026plusmn; 5.72 mmHg, respectively. Following the lunch break, the average values of these biological measurement indicators were 315.27 \u0026plusmn; 89.51 \u0026mu;m, 369.5 \u0026plusmn; 246.3\u0026mu;m\u003csup\u003e3\u003c/sup\u003e, 15.94 \u0026plusmn; 3.16 mmHg, and 37.44 \u0026plusmn; 6.50 mmHg. A statistically significant increased was observed in the average values of CT and CVV before and after the lunch break (paired t-test, both \u003cem\u003ep\u003c/em\u003e\u0026lt;0.05). Significant alterations in CT, CVV, IOP and MOPP were noted across various lunch break schedules (repeated measures ANOVA: F2,2157 = 208.00, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.0001 for CT; F2,2157 = 27.43, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt;0.0001 for CVV; F2,237 = 5.40, \u003cem\u003ep\u003c/em\u003e = 0.0051 for IOP; F2,237 =9.22, \u003cem\u003ep\u003c/em\u003e = 0.0001 for MOPP). The mean choroidal thickening in the LLB, SLB, and NLB groups was determined to be 11.62 \u0026plusmn; 10.39\u0026mu;m, 2.60 \u0026plusmn; 11.46\u0026mu;m, and 1.39 \u0026plusmn; 9.23\u0026mu;m, respectively. A statistically significant difference was observed in the choroidal thickening between the LLB group and the other two lunch break mode groups (pair-wise comparison: both \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.0001). The CVV exhibited increases of 8.5 \u0026plusmn; 22.9\u0026mu;m3, 1.9 \u0026plusmn; 20.3 \u0026mu;m3, and 1.3 \u0026plusmn; 17.9\u0026mu;m3 in the LLB, SLB, and NLB groups, respectively. The data presented in Figure 3 demonstrates a significant correlation between alterations in CT and variations in CVV (simple linear regression analysis: F1,2158 = 306.1, \u003cem\u003ep\u0026nbsp;\u003c/em\u003e\u0026lt; 0.0001).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEffect of different lunch breaks on the choroid of each refractive error group\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to the data presented in Figure 4 a, following LLB, the thickness of the retina increased by 8.06 \u0026plusmn; 14.77\u0026mu;m in the emmetropia and low hyperopia group, 10.25 \u0026plusmn; 8.13\u0026mu;m in the low myopia group, 14.00 \u0026plusmn; 12.20\u0026mu;m in the moderate myopia group, and 12.26 \u0026plusmn; 5.00\u0026mu;m in the high myopia group. There were significant differences in choroidal thickness between the emmetropia and low hyperopia group compared to the moderate myopia group, the low myopia group compared to the moderate myopia group, and the emmetropia and low hyperopia group compared to the high myopia group (Respectively: \u003cem\u003ep\u003c/em\u003e1\u0026lt; 0.0001, \u003cem\u003ep\u003c/em\u003e2=0.0002, \u003cem\u003ep\u003c/em\u003e3=0.0205). Following the administration of SLB, a notable decline in the average magnitude of the overall alteration in the choroid of both eyes was noted in the emmetropia and low hyperopia group, measuring -6.00 \u0026plusmn; 14.17 \u0026mu;m in Figure 4 b. This discrepancy was found to be statistically significant when compared to all other groups (all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.0001). Nevertheless, the group with moderate myopia exhibited the highest mean value of choroidal thickening at 6.27 \u0026plusmn; 13.20 \u0026mu;m, followed by the high myopia group at 5.14 \u0026plusmn; 4.76 \u0026mu;m, and the low myopia group at 0.70 \u0026plusmn; 9.05 \u0026mu;m. The disparities in significance between the low myopia group and the moderate myopia group, as well as between the low myopia group and the high myopia group, were equally pronounced (Respectively : \u003cem\u003ep\u003c/em\u003e1\u0026lt; 0.0001, \u003cem\u003ep\u003c/em\u003e2 =0.008). Following the administration of NLB, choroidal changes were found to be statistically insignificant across all four groups, as indicated by the mean values of changes and the lack of significant differences between groups, as illustrated in Figure 4c (all \u003cem\u003ep\u003c/em\u003e＞0.05).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe choroid plays a role in the regulation of ocular growth, which may have significant implications for the pathogenesis and management of myopia, particularly in the adolescent population\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. OCT has been frequently utilized in prior research to assess choroidal thickness beneath the macula, with certain measurements being obtained through manual means. Previous studies have calculated CVV values using OCT measurement results, however, this approach overlooked the potential impact of the extracellular matrix \u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e,\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. This study employed SS-OCTA utilizing blood flow signals with a scanning frequency of z200,000 times per second to quantify the actual CCV and CT within a 6 x 6mm area. The results of our study indicate that LLB resulted in a mean choroidal thickening of 11.62\u0026micro;m, which was significantly higher than the 2.60\u0026micro;m and 1.39\u0026micro;m thickening observed in the SLB and NLB groups, respectively. The choroid is characterized by having one of the highest blood flow rates among the body's tissues, with medium and large blood vessels playing a significant role in this vascular network \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e, CVV exhibited a similar trend to CT, with LLB resulting in an increase of 0.0085 mm\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, SLB increasing by 0.0019 mm\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, and NLB increasing by 0.0013 mm\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. This further supports the assertion that alterations in CVV play a significant role in influencing changes in CT. Prior research suggests that sleep is intricately linked to the neurobiological regulation of histamine, dopamine, norepinephrine, and the cholinergic system, all of which play a role in vasoconstriction and diastole, ultimately affecting blood flow in the vessels.\u003csup\u003e\u003cspan additionalcitationids=\"CR25 CR26 CR27\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. It can be inferred that LLB is more advantageous in restoring choroidal blood supply under neurohumoral regulation, resulting in an elevation of CVV and subsequent choroidal thickening. Conversely, SLB did not induce substantial choroidal thickening, potentially attributed to the mechanical pressure exerted by the arm on the periocular region, impeding adequate blood supply to the compressed eye. This mechanical pressure caused both an increase in IOP and a decrease in MOPP, further decreasing the blood supply to the choroid and leading to choroidal thinning\u003csup\u003e\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. The thinning of the choroid from noon to afternoon, attributed to rhythmic changes in the choroid and prolonged eye use, appears to be the primary factor contributing to the lack of significant changes in CT and CVV in eyes \u003csup\u003e\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. The IOP exhibited a decrease in NLB and remained unchanged in LLB, a phenomenon that could potentially be attributed to variations in body positioning. Malihi et al.\u003csup\u003e\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003ehighlighted in their research that individuals experience lower ocular pressure while seated compared to when in a supine position.\u003c/p\u003e \u003cp\u003eOur findings demonstrate that as the negative degree of refractive error increases, choroidal thickening becomes more pronounced with LLB and SLB. Of note, individuals in the emmetropia and low hyperopia group exhibited a trend of choroidal thinning during SLB, a phenomenon not previously documented in existing literature. SLB may exert mechanical pressure on the eye due to the positioning of the head on the arms, which is a significant contributing factor to impaired choroidal filling. The choroidal vascular system is supported by fibroblasts that create a scaffold rich in collagen and elastic elements\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e,\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. In the thicker choroid, a higher concentration of fibroblasts results in a greater elastic force, leading to the formation of pronounced gaps; conversely, the thinner choroid contains a lower fibroblast count, resulting in reduced elasticity\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. Our hypothesis posits that the choroid's thickness correlates with its ability to withstand mechanical stress, resulting in more pronounced thinning. This is supported by the absence of substantial choroidal thickening in the low myopia group with SLB. During NLB, there was no statistically significant alteration in choroidal thickness among the various refractive error groups, suggesting that the act of napping may indeed promote choroidal thickening.\u003c/p\u003e \u003cp\u003eThe choroid undergoes rhythmic fluctuations and experiences a thinning process from midday to late afternoon\u003csup\u003e\u003cspan additionalcitationids=\"CR38\" citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. The results of our study indicate that LLB promotes choroidal thickening at midday, and while this thickening may be temporary, Wallman et al.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e observed in their research that transient thickening of the choroid can also impede the growth of axial length. This suggests that varying lunch break modes may have implications for eye development. However, it is important to note the limitations of our study, which was conducted on adult participants. Future research involving child and adolescent populations is necessary to further elucidate the scientific findings. Nonetheless, we advocate for the adoption of LLB, particularly for individuals who have not yet developed myopia.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, lying lunch break is more beneficial for choroidal thickening compared to other postures. Increased CVV is the primary factor contributing to this thickening. Sitting head-on-arms is associated with choroidal thinning in emmetropia and low hyperopia, while moderate myopia shows the most significant CT increase. Incorporating lying lunch break may serve as a potential protective measure against myopia, whereas Sitting head-on-arms lunch breaks may be a risk factor for the development of myopia in children and adolescents.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eCT \u0026nbsp;choroidal thickness\u003c/p\u003e\n\u003cp\u003eCVV \u0026nbsp;choroidal vascular volume\u003c/p\u003e\n\u003cp\u003eIOP \u0026nbsp; intraocular pressure\u003c/p\u003e\n\u003cp\u003eMOPP \u0026nbsp;mean ocular perfusion pressure\u003c/p\u003e\n\u003cp\u003eLLB \u0026nbsp;lying lunch break\u003c/p\u003e\n\u003cp\u003eSLB \u0026nbsp;sitting head-on-arms lunch break\u003c/p\u003e\n\u003cp\u003eNLB \u0026nbsp;sitting no lunch break\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank Jiangdong\u0026nbsp;Hao(Aier Academy of Ophthalmology, Central South University)\u0026nbsp;and Xiaoyun(Aier Institute of Optometry and Vision Science)\u0026nbsp;for his technical assistance in this study.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u003c/strong\u003e\u003cstrong\u003e\u0026rsquo;\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGYR and XNL contributed to the concept of the study. ZWL, QLX, YFY, ZKY,LBW and LZ acquired and analyzed the data. GYR performed software analysis. ZWL, YFY helped with the interpretation of the data. GYR drafted the manuscript. QLX, YFY, ZKY and LBW reviewed and the manuscript. XNL supervised the study. All authors read and approved the fnal manuscript.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHunan Province Optometry Engineering and Technology Research Center(2020TP2003)\u003c/p\u003e\n\u003cp\u003eHunan Province International Cooperation Base for Optometry Science and Technology (2020CB1002)\u003c/p\u003e\n\u003cp\u003eHubei Key R\u0026amp;D Program(2020BCB013)\u003c/p\u003e\n\u003cp\u003eHunan Provincial Natural Foundation（2023JJ70031）\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis observational study received approval from the Ethics Committee of Changsha Aier Eye Hospital (ID:2023KYPJ018) and followed the principles outlined in the Declaration of Helsinki. Prior to participating in the study, all subjects provided written informed consent.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eKrajewski, J., Wieland, R. \u0026amp; Sauerland, M. Regulating strain states by using the recovery potential of lunch breaks. J Occup Health Psychol 15, 131\u0026ndash;139 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBennett, A. A., Gabriel, A. S. \u0026amp; Calderwood, C. Examining the interplay of micro-break durations and activities for employee recovery: A mixed-methods investigation. J Occup Health Psychol 25, 126\u0026ndash;142 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHolden, B. A. \u003cem\u003eet al.\u003c/em\u003e Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology 123, 1036\u0026ndash;1042 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePeng, W., Zhang, Z., Wang, F., Sun, S. \u0026amp; Sun, Y. Association of educational environment with the prevalence of myopia: a cross-sectional study in central China. Front Public Health 11, 1188198 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNickla, D. L. \u0026amp; Wallman, J. The multifunctional choroid. Prog Retin Eye Res 29, 144\u0026ndash;168 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu, R. \u003cem\u003eet al.\u003c/em\u003e Effect of Choroidal Vessel Density on the Ellipsoid Zone and Visual Function in Retinitis Pigmentosa Using Optical Coherence Tomography Angiography. Invest Ophthalmol Vis Sci 60, 4328\u0026ndash;4335 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLinsenmeier, R. A., Goldstick, T. K., Blum, R. S. \u0026amp; Enroth-Cugell, C. Estimation of retinal oxygen transients from measurements made in the vitreous humor. Exp Eye Res 32, 369\u0026ndash;379 (1981).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWei, S.-F. \u003cem\u003eet al.\u003c/em\u003e Sleep Duration, Bedtime, and Myopia Progression in a 4-Year Follow-up of Chinese Children: The Anyang Childhood Eye Study. Invest Ophthalmol Vis Sci 61, 37 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee, S. S. Y., Nilagiri, V. K. \u0026amp; Mackey, D. A. Sleep and eye disease: A review. Clin Exp Ophthalmol 50, 334\u0026ndash;344 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eScuderi, G. \u003cem\u003eet al.\u003c/em\u003e Short-Term Effects of Dark Chocolate on Retinal and Choriocapillaris Perfusion in Young, Healthy Subjects Using Optical Coherence Tomography Angiography. Nutrients 12, 664 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOstrin, L. A., Jnawali, A., Carkeet, A. \u0026amp; Patel, N. B. Twenty-four hour ocular and systemic diurnal rhythms in children. Ophthalmic Physiol Opt 39, 358\u0026ndash;369 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu, X. N. \u003cem\u003eet al.\u003c/em\u003e Sleeping late is a risk factor for myopia development amongst school-aged children in China. Sci Rep 10, 17194 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eProusali, E., Dastiridou, A., Ziakas, N., Androudi, S. \u0026amp; Mataftsi, A. Choroidal thickness and ocular growth in childhood. Surv Ophthalmol 66, 261\u0026ndash;275 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhu, X., Park, T. W., Winawer, J. \u0026amp; Wallman, J. In a matter of minutes, the eye can know which way to grow. Invest Ophthalmol Vis Sci 46, 2238\u0026ndash;2241 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNickla, D. L. Ocular diurnal rhythms and eye growth regulation: where we are 50 years after Lauber. Exp Eye Res 114, 25\u0026ndash;34 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrading diabetic retinopathy from stereoscopic color fundus photographs\u0026ndash;an extension of the modified Airlie House classification. ETDRS report number 10. Early Treatment Diabetic Retinopathy Study Research Group. Ophthalmology 98, 786\u0026ndash;806 (1991).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVan Keer, K., Breda, J. B., Pinto, L. A., Stalmans, I. \u0026amp; Vandewalle, E. Estimating Mean Ocular Perfusion Pressure Using Mean Arterial Pressure and Intraocular Pressure. Invest Ophthalmol Vis Sci 57, 2260 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOstrin, L. A. \u003cem\u003eet al.\u003c/em\u003e IMI-The Dynamic Choroid: New Insights, Challenges, and Potential Significance for Human Myopia. Invest Ophthalmol Vis Sci 64, 4 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSs, L. \u003cem\u003eet al.\u003c/em\u003e Choroidal Thickening During Young Adulthood and Baseline Choroidal Thickness Predicts Refractive Error Change. Investigative ophthalmology \u0026amp; visual science 63, (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTian, F. \u003cem\u003eet al.\u003c/em\u003e Choroidal and Retinal Thickness and Axial Eye Elongation in Chinese Junior Students. Invest Ophthalmol Vis Sci 62, 26 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang, J. C. \u003cem\u003eet al.\u003c/em\u003e Diabetic Choroidopathy: Choroidal Vascular Density and Volume in Diabetic Retinopathy With Swept-Source Optical Coherence Tomography. Am J Ophthalmol 184, 75\u0026ndash;83 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLa\u0026iacute;ns, I. \u003cem\u003eet al.\u003c/em\u003e Choroidal Changes Associated With Subretinal Drusenoid Deposits in Age-related Macular Degeneration Using Swept-source Optical Coherence Tomography. Am J Ophthalmol 180, 55\u0026ndash;63 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlm, A. \u0026amp; Bill, A. Ocular and optic nerve blood flow at normal and increased intraocular pressures in monkeys (Macaca irus): a study with radioactively labelled microspheres including flow determinations in brain and some other tissues. Exp Eye Res 15, 15\u0026ndash;29 (1973).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMesulam, M. M., Mufson, E. J., Wainer, B. H. \u0026amp; Levey, A. I. Central cholinergic pathways in the rat: an overview based on an alternative nomenclature (Ch1-Ch6). Neuroscience 10, 1185\u0026ndash;1201 (1983).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHobson, J. A., McCarley, R. W. \u0026amp; Wyzinski, P. W. Sleep cycle oscillation: reciprocal discharge by two brainstem neuronal groups. Science 189, 55\u0026ndash;58 (1975).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAston-Jones, G. \u0026amp; Bloom, F. E. Activity of norepinephrine-containing locus coeruleus neurons in behaving rats anticipates fluctuations in the sleep-waking cycle. J Neurosci 1, 876\u0026ndash;886 (1981).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBerridge, C. W., Page, M. E., Valentino, R. J. \u0026amp; Foote, S. L. Effects of locus coeruleus inactivation on electroencephalographic activity in neocortex and hippocampus. Neuroscience 55, 381\u0026ndash;393 (1993).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiegel, J. M. \u0026amp; Boehmer, L. N. Narcolepsy and the hypocretin system\u0026ndash;where motion meets emotion. Nat Clin Pract Neurol 2, 548\u0026ndash;556 (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRead, S. A. \u003cem\u003eet al.\u003c/em\u003e The short-term influence of elevated intraocular pressure on axial length. Ophthalmic Physiol Opt 31, 398\u0026ndash;403 (2011).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePetersen, L. G. \u003cem\u003eet al.\u003c/em\u003e Gravitational effects on intraocular pressure and ocular perfusion pressure. J Appl Physiol (1985) 132, 24\u0026ndash;35 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee, T.-E., Yoo, C. \u0026amp; Kim, Y. Y. Effects of different sleeping postures on intraocular pressure and ocular perfusion pressure in healthy young subjects. Ophthalmology 120, 1565\u0026ndash;1570 (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAptel, F., Weinreb, R. N., Chiquet, C. \u0026amp; Mansouri, K. 24-h monitoring devices and nyctohemeral rhythms of intraocular pressure. Prog Retin Eye Res 55, 108\u0026ndash;148 (2016).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMalihi, M. \u0026amp; Sit, A. J. Effect of head and body position on intraocular pressure. Ophthalmology 119, 987\u0026ndash;991 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGelman, S. \u003cem\u003eet al.\u003c/em\u003e The presence and distribution of elastin in the posterior and retrobulbar regions of the mouse eye. Exp Eye Res 90, 210\u0026ndash;215 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQuigley, H. A., Dorman-Pease, M. E. \u0026amp; Brown, A. E. Quantitative study of collagen and elastin of the optic nerve head and sclera in human and experimental monkey glaucoma. Curr Eye Res 10, 877\u0026ndash;888 (1991).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWildsoet, C. \u0026amp; Wallman, J. Choroidal and scleral mechanisms of compensation for spectacle lenses in chicks. Vision Res 35, 1175\u0026ndash;1194 (1995).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNickla, D. L., Wildsoet, C. \u0026amp; Wallman, J. Visual influences on diurnal rhythms in ocular length and choroidal thickness in chick eyes. Exp Eye Res 66, 163\u0026ndash;181 (1998).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNickla, D. L., Wildsoet, C. F. \u0026amp; Troilo, D. Diurnal rhythms in intraocular pressure, axial length, and choroidal thickness in a primate model of eye growth, the common marmoset. Invest Ophthalmol Vis Sci 43, 2519\u0026ndash;2528 (2002).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStone, R. A. \u003cem\u003eet al.\u003c/em\u003e Diurnal axial length fluctuations in human eyes. Invest Ophthalmol Vis Sci 45, 63\u0026ndash;70 (2004).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003eTable 1 is available in the Supplementary Files section.\u003c/p\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":"choroidal thickness, choroidal vascular volume, lunch break, myopia","lastPublishedDoi":"10.21203/rs.3.rs-4652335/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4652335/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe choroid is crucial in myopia prevention and control research. This study aimed to investigate the effects of different lunch break postures and refractive errors on choroidal thickness (CT) and choroidal vascular volume (CVV).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eHealthy adult participants underwent a 45-minute lunch break in three different postures on consecutive days: lying lunch break, sitting head-on-arms lunch break, and sitting no lunch break. SS-OCTA measured CT and CVV in the macula before and after each lunch break. Changes in CT were also evaluated across different refractive errors.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eAmong 40 adults (80 eyes), the average CT change was 11.62\u0026micro;m for lying lunch break, significantly higher than sitting head-on-arms lunch break (2.60\u0026micro;m) and sitting no lunch break (1.39\u0026micro;m) (both \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). Average CVV changes were 8.5\u0026micro;m\u0026sup3; for lying lunch break, 1.9\u0026micro;m\u0026sup3; for sitting head-on-arms lunch break, and 1.3\u0026micro;m\u0026sup3; for sitting no lunch break. CT changes strongly correlated with CVV changes (F1,2158\u0026thinsp;=\u0026thinsp;306.1, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). During sitting head-on-arms lunch break, CT decreased by 6.00\u0026thinsp;\u0026plusmn;\u0026thinsp;14.17 \u0026micro;m in the emmetropia and low hyperopia group, significantly different from other groups (all \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eLying down during lunch breaks is most conducive to choroidal thickening, driven by increased CVV. Sitting head-on-arms may lead to choroidal thinning in people with emmetropia or low hyperopia. When considering the development of myopia in children and adolescents, it is suggested that LLB may serve as a protective factor while sitting head-on-arms lunch break may act as a risk factor.\u003c/p\u003e","manuscriptTitle":"Changes of Choroidal Thickness Varied Due to Different Lunch Break Posture and Refractive","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-23 22:03:03","doi":"10.21203/rs.3.rs-4652335/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":"66b73412-f570-4742-b675-968b5b6add7a","owner":[],"postedDate":"July 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":34770616,"name":"Health sciences/Health occupations"},{"id":34770617,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2024-08-29T18:10:12+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-23 22:03:03","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4652335","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4652335","identity":"rs-4652335","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}