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Clinical Relevance: Identification of individuals with a higher risk of developing refractive error under specific gene and environmental backgrounds, especially myopia, could enable more personalized myopic control advice for patients., Background: Refractive error is a common disease that affects visual quality and ocular health worldwide. Its mechanisms have not been elaborated, although both genes and the environment are known to contribute to the process. Interactions between genes and the environment have been shown to exert effects on the onset of refractive error, especially myopia. Axial length elongation is the main characteristic of myopia development and could indicate the severity of myopia. Thus, the purpose of the study was to investigate the interaction between environmental factors and genetic markers of VIPR2 and their impact on spherical equivalence and axial length in a population of Han Chinese children., Methods: A total of 1825 children aged 13~15 years in the Anyang Childhood Eye Study (ACES) were measured for cycloplegic autorefraction, axial length, and height. Saliva DNA was extracted for genotyping three single-nucleotide polymorphisms (SNPs) in the candidate gene (VIPR2). The median outdoor time (2 h/day) was used to categorize children into high and low exposure groups, respectively. Genetic quality control and linear and logistic regressions were performed. Generalized multifactor dimensional reduction (GMDR) was used to investigate gene-environment interactions., Results: There were 1391 children who passed genetic quality control. Rs2071623 of VIPR2 was associated with axial length (T allele, β=-0.11 se=0.04 p=0.006), while SNP nominally interacted with outdoor time (T allele, β=-0.17 se=0.08 p=0.029). Rs2071623 in children with high outdoor exposure had a significant interaction effect on axial length (p=0.0007, β=-0.19 se=0.056) compared to children with low outdoor exposure. GMDR further suggested the existence of an interaction effect between outdoor time and rs2071623., Conclusions: Rs2071623 within VIPR2 could interact with outdoor time in Han Chinese children. More outdoor exposure could enhance the protective effect of the T allele on axial elongation., (Copyright © 2023 Molecular Vision.)

Purpose: To assess the repeatability and agreement between Scheimpflug-based corneal topographers, Scansys and Pentacam, in measuring ocular parameters in myopic eyes., Setting: Grade-A tertiary hospital in Beijing, China., Design: Cross-sectional study., Methods: The following measurements were performed in 204 subjects undergoing preoperative examinations for refractive surgery from the corneal curvature, astigmatism, corneal thickness, corneal volume, corneal asphericity, anterior chamber depth (ACD) and volume (ACV), and pupil diameters. Repeatability was determined using intraclass correlation coefficient with 95% CI, Cronbach α, coefficient of variation, within-subject SD, test-retest repeatability, and 1-way analysis of variance (1-way analysis of variance). The interdevice agreement was determined using paired t test and Bland-Altman plots., Results: Scansys showed good repeatability in the anterior and posterior corneal flattest meridian (Kf), steepest meridian (Ks), and mean (Km); axis of anterior corneal Ks; anterior corneal astigmatism; pupil central corneal thickness (CCT); CCT; corneal apex thickness; thinnest corneal thickness; corneal volume; photopic pupil diameter; ACD; and ACV. In the agreement study, Bland-Altman plots showed that 95% limit of agreement of corneal curvature, pupil CCT, corneal apex thickness, thinnest corneal thickness, and corneal volume generated by Scansys and Pentacam were narrow. There were no statistically significant differences in the anterior corneal Kf and Km., Conclusions: Scansys showed good repeatability in measuring corneal curvature of anterior and posterior surfaces, anterior corneal astigmatism, corneal thickness, corneal volume, photopic pupil diameter, ACV, and ACD. Scansys and Pentacam can only be used interchangeably in measuring anterior corneal curvature., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Background: This study used spectral-domain optical coherence tomography (SD-OCT) imaging to describe the distribution of macular ganglion cell complex (GCC) thickness and its association with ocular and systemic parameters in 7-year-old children in China., Methods: The study involved a school-based, cross-sectional analysis of the Anyang Childhood Eye Study (ACES) and included 2,505 first-grade students from urban areas in Anyang, Henan Province, Central China. All participants underwent systemic and ocular examinations. Both GCC and retinal nerve fiber layer (RNFL) thickness were measured using the iVue-100 OCT (Optovue, Fremont, CA, USA). Intraocular pressure (IOP) was recorded with noncontact tonometer (Huvitz, HNT-7000). Axial length (AL) was measured using optical biometry (Lenstar LS 900, Haag-Streit Diagnostics, Koniz, Switzerland)., Results: The mean GCC thickness was 95.31±7.67 µm. GCC thickness had negative associations with AL (r=-0.124, P<0.001), cup-to-disc (C-D) area ratio (r=-0.068, P=0.0033), horizontal C-D (H C-D) ratio (r=-0.048, P=0.0384), and vertical C-D (V C-D) ratio (r=-0.074, P=0.0013). Positive correlations were found with spherical equivalent (SE) (r=0.080, P=0.0001), RNFL thickness (r=0.363, P<0.001), height (r=0.059, P=0.0036), fovea parameters, disc area (r=0.078, P=0.0007), rim area (r=0.115, P<0.001), rim volume (r=0.119, P<0.001), and optic nerve head volume (r=0.097, P<0.001). GCC thickness had no significant association with IOP, age, sex, or weight, waist, or head circumference., Conclusions: This study provides normative GCC data for 7-year-old healthy children in China. The findings support an association between GCC and AL, SE, RNFL, height, and C-D ratio in children., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/tp-21-323). The authors have no conflicts of interest to declare., (2021 Translational Pediatrics. All rights reserved.)

Recently, the distribution characteristics of retinal nerve fiber layer thickness in myopic population have raised scholars' attention. The retinal nerve fiber layer thickness is varied with different refractive statuses, and is correlated to many factors like age, eye elongation, and fundus changes. Further exploration of the relationship between myopia and retinal structure and function will promote our understanding and knowledge of the pathogenesis of myopia. The article reviews the structure characteristics of the retinal nerve fiber layer, its associations with demographic characteristics, its characteristics in myopia, and the structural-functional relationship.

Objective: To investigate the distribution of spherical equivalent and ocular biometric parameters in a population of grade 7 children in central China., Methods: 2 363 grade 7 students of junior high schools were randomly sampled. The students have been examined at baseline and followed up annually. Detailed questionnaires and most of the ocular examinations were performed. Spherical equivalent (Seq) was calculated as sphere +1/2 cylinder from cycloplegic autorefraction. Myopia was defined as spherical equivalent ≤ -0.5D, hyperopia as spherical equivalent ≥ +0.5D and emmetropia between -0.5D and +0.5D. The Lensar LS900 was used to measure corneal curvatures, axial length and anterior chamber depth. Right eyes results were analyzed., Results: Among 2 267 children who have the baseline examination, 1 839 children participated the follow up examination(response rate, 81.1%), with an mean age of 14.7 years (range, 12.9-17.6) and male ratio of 48.4%. The mean spherical equivalent refraction was (-2.62 ± 2.19)D. The prevalence rates of myopia, high myopia, emmetropia and hyperopia were 82.7%, 7.1%, 9.8% and 7.5%. The cumulative incidence rates of myopia and high myopia were 47.1% and 4.5% respectively. Axial length, anterior chamber depth, and corneal curvature were normally distributed. The mean axial length, anterior chamber depth, and corneal curvature were (24.8 ± 1.1)mm, (3.18 ± 0.25)mm, (42.8 ± 1.4)D and (43.9 ± 1.6)D respectively. Axial length was longer, anterior chamber depth was deeper, and corneal were flatter in the male(P = 0.000). Axial length and anterior chamber depth correlated negatively with refraction., Conclusions: A moderate myopic distribution of refraction was present in the grade 9 students in central China. The prevalence rates of myopia and high myopia were relatively high in this 14-year-old population compared to other countries. It is necessary to strengthen the prevention of juvenile myopia.