Refractive error, visual acuity and causes of vision loss in children in Shandong, China. The Shandong Children Eye Study

Mechanisms of emmetropization and what might go wrong in myopia

Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, the myopic retina has reduced ability to inhibit eye growth when positive defocus is imposed. (3) The bi-directional response of the emmetropic retina is elicited with low spatial frequency information below 8 cyc/deg, which makes it unlikely that optical higher-order aberrations play a role. (4) The retinal mechanism for the detection of the sign of defocus involves a comparison of defocus blur in the blue (S-cone) and red end of the spectrum (L + M-cones) but, again, the myopic retina is not responsive, at least not in short-term experiments. This suggests that it cannot fully trigger the inhibitory arm of the emmetropization feedback loop. As a result, with an open feedback loop, myopia development becomes "open-loop".

Normative value of hyperopia reserve and myopic shift in Chinese children and adolescents aged 3-16 years

BACKGROUND

This research aims to generate normative values of hyperopia reserve and refractive progression as effective tools to estimate the risk of myopia.

METHODS

A 1-year follow-up study was conducted among Chinese children and adolescents aged 3-16 years selected from schools and kinder gardens using cluster sampling. All participants underwent examinations including visual acuity, axial length and cycloplegic autorefraction (1% cyclopentolate). Percentiles of spherical equivalent (SE) were calculated using Lambda-Mu-Sigma (LMS) method. Age-specific refractive progression and hyperopia reserve were determined by backward calculation.

RESULTS

Of 3118 participants, 1702 (54.6%) were boys with a mean baseline age of 7.30 years. The 50th percentile of SE estimated by LMS decreased from 1.04 D at 3 years to -2.04 D at 16 years in boys, while from 1.29 D to -2.81 D in girls. The 1-year refractive progression of myopes (0.81 D) was greater than that of non-myopes (0.51 D). The normative value of hyperopia reserve was 2.64 (range: 2.40 D-2.88 D) at 3 years and -0.35 (range: -0.50 to -0.17) D at 16 years, with the maximum progression of 0.35 D at the age of 6 years.

CONCLUSION

Age-specific normative values of hyperopia reserve and yearly myopic shift in children and adolescents aged 3-16 years were provided, helping identify and monitor myopia and giving prevention in advance.

Pseudomyopia as an independent risk factor for myopia onset: a prospective cohort study among school-aged children

AIM

To investigate whether pseudomyopia is an independent risk factor for myopia onset based on a population-based cohort study.

METHODS

Non-myopic children were recruited from schools in rural and urban settings of Shangdong province, China. Baseline examinations started in September 2020 and all participants were invited for a 6-month follow-up. Pseudomyopia was defined as spherical equivalent (SE) ≤-0.50 diopters (D) before cycloplegia and >-0.50D after cycloplegia. Myopia was defined as cycloplegic SE ≤-0.50D.

RESULTS

A total of 2328 children (baseline age: 4-17 years) were included in the final analysis. During the 6-month follow-up, 21.1% (355/1680) pseudomyopic eyes developed myopia, and 3.8% (110/2879) non-myopic and non-pseudomyopic eyes developed myopia. After adjusting for multiple myopia risk factors, including baseline cycloplegic SE, near work and outdoor time, pseudomyopia was found to be an independent risk factor for myopia onset (relative risk=2.52, 95% CI 1.86 to 3.42). Additionally, pseudomyopic children with more myopic cycloplegic SE (p<0.001), smaller difference between cycloplegic and non-cycloplegic SE (DIFF, p<0.001), and higher binocular amplitude of accommodation (p<0.001) had higher risk of myopia development.

CONCLUSION

This is an important longitudinal study to prove that pseudomyopia is an independent risk factor for myopia development among school-aged children.

Myopia Is an Ischemic Eye Condition: A Review from the Perspective of Choroidal Blood Flow

Myopia is a common refractive error that affects a large proportion of the population. Recent studies have revealed that alterations in choroidal thickness (ChT) and choroidal blood flow (ChBF) play important roles in the progression of myopia. Reduced ChBF could affect scleral cellular matrix remodeling, which leads to axial elongation and further myopia progression. As ChT and ChBF could be used as potential biomarkers for the progression of myopia, several recent myopia treatments have targeted alterations in ChT and ChBF. Our review provides a comprehensive overview of the recent literature review on the relationship between ChBF and myopia. We also highlight the importance of ChT and ChBF in the progression of myopia and the potential of ChT as an important biomarker for myopia progression. This summary has significant implications for the development of novel strategies for preventing and treating myopia.

Role of lens in early refractive development: evidence from a large cohort of Chinese children

AIMS

To document longitudinal changes in spherical equivalent refraction (SER) and related biometric factors during early refractive development.

METHODS

This was a prospective cohort study of Chinese children, starting in 2018 with annual follow-ups. At each visit, children received cycloplegic autorefraction and ocular biometry measurements. Lens power (LP) was calculated using Bennett's formula. Children were divided into eight groups based on baseline age: the 3-year-old (n=426, 49.77% girls), 4-year-old (n=834, 47.36% girls), 6-year-old (n=292, 46.58% girls), 7-year-old (n=964, 43.46% girls), 9-year-old (n=981, 46.18% girls), 10-year-old (n=1181, 46.32% girls), 12-year-old (n=504, 49.01%) and 13-year-old (n=644, 42.70%) age groups.

RESULTS

This study included right-eye data from 5826 children. The 3-year-old and 4-year-old age groups demonstrated an inflection point in longitudinal SER changes at a mild hyperopic baseline SER (+1 to +2 D), with children with more myopic SER showing hyperopic refractive shifts while those with more hyperopic SER showing myopic shifts. The hyperopic shift in SER was mainly attributed to rapid LP loss and was rarely seen in the older age groups. Axial elongation accelerated in the premyopia stage, accompanied by a partially counter-balancing acceleration of LP loss. For children aged 3-7 years, those with annual SER changes <0.25 D were all mildly hyperopic at baseline (mean: 1.23 D, 95% CI 1.20 to 1.27 D).

CONCLUSION

Our findings suggest that during early refractive development, refractions cluster around or above +1.00 D. There is a pushback process in which increases in the rate of LP occur in parallel with increases in axial elongation.

Prevalence and associated factors of myopia in children and adolescents in Russia: the Ural Children Eye Study

BACKGROUND

To assess the prevalence of myopia and the distribution of ocular axial length as surrogate for myopic refractive error in school children in a population in Russia.

METHODS

The Ural Children Eye Study, a school-based case-control study, was conducted in Ufa/Bashkortostan/Russia from 2019 to 2022 and included 4933 children (age: 9.7±2.6 years; range: 6.2-18.8 years). The parents underwent a detailed interview and the children an ophthalmological and general examination.

RESULTS

Prevalence of any myopia (≤-0.50 dioptres (D)), minor myopia (-0.50 D to -1.0 D), moderate myopia (-1.01 D to -5.99 D) and high myopia (≤-6.0D) was 2187/3737 (46.2%; 95% CI 44.8% to 48.6%), 693/4737 (14.6%; 95% CI 13.6% to 15.6%), 1430/4737 (30.2%; 95% CI 28.9% to 31.5%) and 64/4737 (1.4%; 95% CI 1.0% to 1.7%), respectively. In the children aged 17+ years, prevalence of any, minor, moderate and high myopia was 170/259 (65.6%; 95% CI 59.8% to 71.5%), 130/259 (50.2%; 95% CI 44.1% to 56.3%), 28/259 (10.8%; 95% CI 7.0% to 14.6%) and 12/259 (4.6%; 95% CI 2.1% to 7.2%), respectively. After adjusting for corneal refractive power (beta: 0.09) and lens thickness (beta: -0.08), larger myopic refractive error was associated (r2=0.19) with older age (beta: 0.33), female sex (beta: 0.04), higher prevalence of maternal (beta: 0.15) and paternal (beta: 0.12) myopia, more time spent in school, with reading books or playing with the cell phone (beta: 0.05) and less total time spent outdoors (beta: 0.05). Axial length and myopic refractive error increased by 0.12 mm (95% CI 0.11 to 0.13) and -0.18 D (95% CI 0.17 to 0.20), respectively, per year of age.

CONCLUSIONS

In this ethnically mixed urban school children population from Russia, prevalence of any myopia (65.6%) and high myopia (4.6%) in children aged 17+ years was higher than in adult populations in the same region and it was lower than in East Asian school children, with similar associated factors.

Prevalence of Myopic Maculopathy Among the Very Old: The Ural Very Old Study

Purpose

To assess the prevalence of myopic macular degeneration (MMD) in very old individuals.

Methods

The population-based Ural Very Old Study (UVOS) included 1526 (81.1%) of 1882 eligible inhabitants aged ≥85 years. Assessable fundus images were available for 930 (60.9%) individuals (mean age, 88.6 ± 2.7 years). MMD was defined by macular patchy atrophies (i.e., MMD stage 3 and 4 as defined by the Pathologic Myopia Study Group).

Results

MMD prevalence was 21 of 930 (2.3%; 95% CI, 1.3-3.3), with 10 individuals (1.1%; 95% CI, 0.4-1.7) having MMD stage 3 and 11 participants (1.2%; 95% CI, 0.5-1.9) MMD stage 4 disease. Within MMD stage 3 and 4, prevalence of binocular moderate to severe vision impairment was 4 of 10 (40%; 95% CI, 31-77) and 7 of 11 (64%; 95% CI, 30-98), respectively, and the prevalence of binocular blindness was 2 of 10 (20%; 95% CI, 0-50) and 3 of 11 (27%; 95% CI, 0-59), respectively. In minor myopia (axial length, 24.0 to <24.5 mm), moderate myopia (axial length, 24.5 to <26.5 mm), and high myopia (axial length, ≥26.5 mm), MMD prevalence in the right eyes was 0 of 46 eyes (0%), 3 of 40 eyes (8%; 95% CI, 0-16), and 7 of 9 (78%; 95% CI, 44-100), respectively; MMD prevalence in the left eyes was 1 in 48 eyes (2%; 95% CI, 0-6), 4 of 36 eyes (11%; 95% CI, 0-22), and 3 of 4 eyes (75%; 95% CI, 0-100), respectively. In multivariable analysis, a higher MMD prevalence (odds ratio, 8.89; 95% CI, 3.43-23.0; P < 0.001) and higher MMD stage (beta, 0.45; B, 19; 95% CI, 0.16-0.22; P < 0.001) were correlated with longer axial length but not with any other ocular or systemic parameter.

Conclusions

MMD prevalence (stages 3 and 4) in very old individuals increased 8.89-fold for each mm axial length increase, with a prevalence of ≥75% in highly myopic eyes. In old age, highly myopic individuals have a high risk of eventually developing MMD with marked vision impairment.

Associations between axial length, corneal refractive power and lens thickness in children and adolescents: The Ural Children Eye Study

PURPOSE

To assess relationships between ocular biometric parameters in dependence of age and sex in children and adolescents.

METHODS

In the Ural Children Eye Study, a school-based cohort study, 4933 children underwent an ophthalmological and general examination.

RESULTS

Complete biometric measurements were available for 4406 (89.3%) children. Cycloplegic refractive error (mean: -0.87 ± 1.73 diopters (D); median: -0.38 D; range: -19.75 D to +11.25 D) increased (multivariable analysis; r2  = 0.73) with shorter axial length (β: -0.99; non-standardized regression coefficient B: -1.64; 95% CI: -1.68, -1.59) and lower corneal refractive power (β: -0.55; B: -0.67; 95% CI: -0.70, -0.64), in addition to higher cylindrical refractive error (β: 0.10; B: 0.34; 95% CI: 0.27, 0.41), thinner lens (β: -0.11; -0.85; 95% CI: -1.02, -0.69) and male sex (β: 0.15; B: 0.50; 95% CI: 0.42, 0.57). In univariate analysis, decrease in refractive error with older age was more significant (β: -0.38 vs. β: -0.25) and steeper (B: -0.22 (95% CI: -0.24, -0.20) vs. B: -0.13 (95% CI: -0.15, -0.11)) in girls than boys, particularly for an age of 11+ years. Axial length increased with older age (steeper for age <11  years) (B: 0.22 (95% CI: 0.18, 0.25) vs. 0.07 (95% CI: 0.05, 0.09)). In multivariable analysis, axial length increased with lower refractive error (β: -0.77; B: -0.42; 95% CI: -0.43, -0.40) and lower corneal refractive power (β: -0.54; B: -0.39; 95% CI: -0.41, -0.38), in addition to older age (β: 0.04; B: 0.02; 95% CI: 0.01, 0.03), male sex (β: 0.13; B: 0.23; 95% CI: 0.21, 0.32), higher cylindrical refractive error (β: 0.05; B: 0.09; 95% CI: 0.05, 0.14) and thinner lens (β: -0.14; B: -0.62; 95% CI: -0.72, -0.51). The axial length/corneal curvature (AL/CR) ratio increased until the age of 14 years (β: 0.34; B: 0.017; 95% CI: 0.016, 0.019; p < 0001), and then became independent of age. The AL/CR ratio increased (r2  = 0.78) mostly with higher corneal refractive power (β: 0.25; B: 0.02; 95% CI: 0.02, 0.02; p < 0.001), lower refractive error (β: -0.75; B: -0.05; 95% CI: -0.05, -0.05; p < 0.001), thinner lens thickness (β: -01.6; B: -0.09; 95% CI: -0.10, -0.08; p < 0.001) and older age (β: 0.16; B: 0.006; 95% CI: 0.005, 0.007; p < 0.001).

CONCLUSIONS

In this multiethnic group of school children in Russia, the age-related increase in myopic refractive error was more significant and steeper in girls, particularly for the age group of 11+ years. Determinants of higher myopic refractive error were longer axial length, higher corneal refractive power, lower cylindrical refractive error, thicker lens and female sex.

Cylinder power progression associated with axial length in young children: a two-year follow-up study

PURPOSE

To describe the association of refraction development and axial length (AL) in young children and provide new insights into the progression of cylinder power.

METHODS

Children (2-3 grades) were enrolled from primary schools in Shanghai and followed up for two years. Cycloplegic refraction, AL, and corneal curvature radius were measured. Refraction parameters were compared among groups with different AL, AL1 (AL < 23.5 mm), AL2 (23.5 mm ≤ AL < 24.5 mm), and AL3 (AL ≥ 24.5 mm). Multiple regression analysis was used to explore risk factors of diopter of cylinder (DC) progression.

RESULTS

In total, out of 6891 enrolled children, 5961 participants (7-11 yrs) were included in the final analysis. Over the two-year period, the cylinder power significantly changed, and those with longer AL had more rapid DC progression over the two years (AL1, -0.09 ± 0.35 D; AL2, -0.15 ± 0.39 D; AL3, -0.29 ± 0.44 D) (P < 0.001). The change in DC was independently associated with AL at baseline (P < 0.001). The proportion of with-the-rule astigmatism increased from 91.3% to 92.1% in AL1 group, from 89.1% to 91.8% in AL2 group and from 87.1% to 92.0% in AL3 group.

CONCLUSIONS

Young children with long AL experienced rapid progression of cylinder power. Both the control of myopia progression and attention to the correction of astigmatism are necessary in the health management of children with long AL. The significantly increased AL in participants might contribute to both the extent and direction of astigmatism.

Spatial epidemiological characteristics and driving factors of myopia among school-age children based on geographical detector: a national study

The present study aimed to examine the spatial characteristics of myopia and identify the socioeconomic and environmental factors influencing its prevalence. Myopia prevalence among children of school age of Han ethnicity in China was 56.6% in 2019, with the highest and lowest prevalence's in Shandong (66.8%) and Guizhou (47.3%), respectively. There was a spatial aggregation of myopia prevalence in China. Environmental factors (atmospheric PM2.5 concentration and forest coverage) and socioeconomic factors (gross domestic product per capita, per capita disposable income, hospital beds per thousand people, and Engel coefficient) have significant influences on myopia prevalence. The interaction of each factor on myopia showed nonlinear enhancement. Myopia prevalence among children of school age was spatially clustered, and environmental and socioeconomic conditions are associated with myopia prevalence. Our findings provide novel perspectives for the comprehensive prevention and control of myopia.

Comparison of the new self-contained darkroom refractive screener versus table-top autorefractor and cycloplegia retinoscopy in detecting refractive error

PURPOSE

By comparing the results of the new self-contained darkroom refractive screener (YD-SX-A) versus table-top autorefractor and cycloplegic retinoscopy, to evaluate the performance of the YD-SX-A in detecting refractive error in children and adolescents and then judge whether it can be used in refractive screening.

METHODS

Cross-sectional study. 1000 participants between the ages of 6 and 18 who visited the Optometry Center of the People's Hospital of Guangxi Zhuang Autonomous Region from June to December 2022 were selected. First, participants were instructed to measure their diopter with a table-top autorefractor (Topcon KR8800) and YD-SX-A in a noncycloplegic setting. After cycloplegia, they were retinoscopy by a professional optometrist. The results measured by three methods were collected respectively. To avoid deviation, only the right eye (1000 eyes) data were used in the statistical analysis. The Bland-Altman plots were used to evaluate the agreement of diopters measured by the three methods. The receiver operating characteristic (ROC) curves was used to analysis effectiveness of detecting refractive error of YD-SX-A.

RESULTS

The average age of participants was 10.77 ± 3.00 years, including 504 boys (50.4%) and 496 girls (49.6%). When YD-SX-A and cycloplegia retinoscopy (CR) were compared in the myopia group, there was no statistical difference in spherical equivalent (SE) (P > 0.05), but there was a statistical difference in diopter spherical (DS) and diopter cylinder (DC) (P < 0.05). Comparing the diopter results of Topcon KR8800 and CR, the difference between each test value in the myopia group was statistically significant (P < 0.05). In the hyperopia group, the comparison between YD-SX-A and CR showed no statistically significant differences in the DC (P > 0.05), but there were significant differences in the SE and DS (P < 0.05). In the astigmatism group, the SE, DS, and DC were statistically different, and the DC of YD-SX-A was lower than that of CR and Topcon KR8800. Bland-Altman plots indicated that YD-SX-A has a moderate agreement with CR and Topcon KR8800. The sensitivity and specificity of YD-SX-A for detecting myopia, hyperopia and astigmatism were 90.17% and 90.32%, 97.78% and 87.88%, 84.08% and 74.26%, respectively.

CONCLUSION

This study has identified that YD-SX-A has shown good performance in both agreement and effectiveness in detecting refractive error when compared with Topcon KR8800 and CR. YD-SX-A could be a useful tool for large-scale population refractive screening.

Refractive and corneal astigmatism in Chinese 4-15 years old children: prevalence and risk factors

BACKGROUND

To investigate the prevalence and risk factors of refractive astigmatism (RA) and corneal astigmatism (CA) in preschool children and school-aged children in Shanghai, China.

METHODS

In this school-based, cross-sectional study, 4-15 years old children across three learning stages of kindergarten, primary school, and junior high school underwent noncycloplegic autorefraction and completed comprehensive questionnaires involving time spent on daily homework and outdoor activities. Data from the right eyes were analysed.

RESULTS

Overall, 7084 children (mean ± standard deviation (SD) of age: 8.08 ± 3.11 years) were included, and the prevalence rates of RA/CA ( ≤ - 1.0 D) in children were 15.8%/64% in kindergartens, 16.5%/65% in primary schools, and 32.8%/76.9% in junior high schools. The magnitude and prevalence of RA and CA all increased with age or with learning stage (all P < 0.001). The presence of RA was associated with more myopic spherical power (odds ratio (OR) 0.956, P = 0.021), junior high school (OR 1.973, P < 0.001), longer homework time on weekdays (OR 1.074, P = 0.029), and shorter outdoor activity time on weekends (odds ratio 0.929, P = 0.013).

CONCLUSION

In the wide age range of 4 to 15 years, the magnitude and prevalence of RA and CA increased with the learning stage, and these increases mainly began at the primary school stage. Factors, including longer homework time and shorter outdoor time were correlated with the presence of RA.

Prevalence Trend of Myopia during the Post-COVID-19 Epidemic Period among Preschoolers: A Prospective School-based Study

SIGNIFICANCE

Changes in behavior and lifestyle during the post-coronavirus disease 2019 (COVID-19) epidemic may have some impact on myopia rates in preschoolers, and exploring the changes in myopia rates in preschool children may inform the formulation of myopia prevention and control policies.

PURPOSE

This study aimed to investigate the prevalence of myopia in preschool children during the post-COVID-19 epidemic period in Xuzhou, China.

METHODS

A series of cross-sectional school-based studies was conducted. A total of 117,632 preschool children aged 3 to 6 years were subjected to annual vision screening from 2019 to 2021. Spot photo screening was used to record the spherical equivalent refraction for each child and to analyze the prevalence of myopia by age, sex, and region during the post-COVID-19 epidemic period.

RESULTS

A total of 113,979 preschool children were included in the analysis, of whom 60,784 (53.3%) were male and 53,195 (46.7%) were female. For all children, the mean ± standard deviation spherical equivalent refraction in 2019, 2020, and 2021 was +0.32 ± 0.50, +0.34 ± 0.55, and +0.34 ± 0.54 D, respectively (all P < .05), indicative of a very slight hyperopic shift. In all age groups, the change in mean spherical equivalent refraction and its distribution were relatively stable. From 2019 to 2021, the overall prevalence of myopia in preschool children was 3.1, 3.3, and 3.5%, respectively. The rise in myopia rates was minimal. The largest increase in the annual prevalence of myopia was seen among children aged 6 years, at 0.5%, followed by those aged 5 years (0.4%) and aged 3 years (0.4%). The prevalence was higher in boys than girls and in urban versus rural areas.

CONCLUSIONS

During the post-COVID-19 epidemic period, the refractive status of Xuzhou preschool children remained stable.

Intraocular Pressure and Myopia Progression, Axial Length Elongation in Rural Chinese Children

SIGNIFICANCE

This study reported the relationship between intraocular pressure (IOP) and myopia progression, which helps to understand more comprehensively whether IOP can be an important reference factor to intervene in the progression of myopia.

PURPOSE

This study aimed to investigate the association between IOP and myopia progression as well as axial length elongation in rural Chinese children.

METHODS

A total of 598 (598 of 878 [68.1%]) children (6 to 17 years) from the baseline Handan Offspring Myopia Study who completed a 3.5-year follow-up vision examination were included. Ocular examinations at both visits included cycloplegic autorefraction, IOP, and axial length measurements.

RESULTS

Children with myopia had the highest baseline IOP of the three refractive groups (14.13 ± 1.31, 13.78 ± 1.71, and 13.59 ± 1.64 mmHg in myopes, emmetropes, and hyperopes, respectively, P = .002). However, IOPs showed no significant difference between eyes with or without newly developed myopia (13.63 ± 1.68 vs. 13.89 ± 1.68, P = .16), with or without faster myopia progression (13.75 ± 1.61 vs. 13.86 ± 1.63, P = .46), or with axial length elongation (13.80 ± 1.61 vs. 13.76 ± 1.64, P = .80). The multivariate regression analysis demonstrated that neither baseline refractive error ( β = -0.082, P = .13) nor baseline axial length ( β = -0.156, P = .08) was associated with baseline IOP.

CONCLUSIONS

Myopic eyes have slightly higher IOP compared with emmetropic and hyperopic eyes, although it was not clinically significant. However, IOP was not found to be associated with either myopia progression or axial length elongation in this cohort sample of rural Chinese children.

Role of corneal radius of curvature in early identification of fundus tessellation in children with low myopia

AIM

To assess the role of the corneal radius of curvature (CR) in the identification of fundus tessellation in children with low myopia.

METHODS

In the cross-sectional study, students aged 9-12 years from 24 primary schools in Shanghai were enrolled by cluster sampling. Participants underwent measurements including cycloplegic refraction and axial length. Fundus images and choroidal thickness were obtained by swept-source optical coherence tomography. Fundus tessellation was classified into four grades according to fundus photographs.

RESULTS

A total of 1127 children with low myopia (spherical equivalence (SE) >-3.00 dioptre (D) but ≤-0.50 D) were included, with a mean age of 10.29±0.60 years and a mean SE of -1.44±0.69 D. Fundus tessellation was found in 591 (52.4%) cases (grade 1: 428, 38.0%; grade 2: 128, 11.4%; grade 3: 35, 3.1%). Choroidal thickness decreased as fundus tessellation grade increased (p trend <0.001). According to regression analysis, higher fundus tessellation grade was independently associated with larger CR (OR, 7.499; 95% CI 2.279 to 24.675, p=0.001). For those with CR >7.9 mm, along with CR, degree and proportion of fundus tessellation increased sharply.

CONCLUSION

Fundus tessellation existed in more than half of children with low myopia. Preliminary fundus photography conducted in children with low myopia with large CR would be necessary and beneficial to the early management of myopic fundus changes. Trial registration number NCT02980445.

Risk Factors for Myopia: A Review

Due to the myopia prevalence increase worldwide, this study aims to establish the most relevant risk factors associated with its development and progression. A review search was carried out using PubMed, Web of Science, and Scopus databases to identify the main myopia risk factors. The inclusion criteria for the articles were those related to the topic, carried out in subjects from 5 to 30 years, published between January 2000 and May 2023, in English, and with the full text available. Myopia etiology has proven to be associated with both genetic and environmental factors as well as with gene-environment interaction. The risk of developing myopia increases in children with myopic parents (one parent ×2 times, two parents ×5 times). Regarding environmental factors, education is the main risk factor correlated with myopia prevalence increase. Further, several studies found that shorter distance (<30 cm) and longer time spent (>30 min) for near work increase the risk of myopia. Meanwhile, increased outdoor activity (>40 min/day) has been shown to be a key factor in reducing myopia incidence. In conclusion, the interventional strategy suggested so far to reduce myopia incidence is an increase in time outdoors and a reduction in the time spent performing near-work tasks.

Orthokeratology for Slowing Myopia Progression in Children: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) on the effects of orthokeratology for slowing myopia progression in children.

METHODS

We performed a specific search on PubMed, Embase, Cochrane Library, Clinical Trials, CNKI, SinoMed, and Wanfang Data for RCTs conducted up to October 1, 2022. We pooled the weighted mean difference (WMD) between the orthokeratology and control groups for axial length (AL) elongation and the odds ratio (OR) for rates of adverse events and dropout.

RESULTS

Seven RCTs involving 655 eyes were included. There were significant differences in the effects of orthokeratology versus control in slowing AL elongation with WMD of -0.11 mm (95% confidence interval (CI), -0.13 to -0.08; P <0.01) at 6 months, -0.16 mm (95% CI, -0.18 to -0.13; P <0.01) at 12 months, -0.23 mm (95% CI, -0.29 to -0.18; P <0.01) at 18 months, and -0.28 mm (95% CI, -0.38 to -0.19; P <0.01) at 24 months, respectively. Myopia control rate declined, with 64%, 53%, 50%, and 47% recorded for 6, 12, 18, and 24 months, respectively. There was no statistical significance for adverse events between orthokeratology and control groups (OR=2.63, 95% CI, 0.72-9.61; P =0.11).

CONCLUSION

Orthokeratology can effectively slow myopia progression in children, and the efficacy of myopia control decreases with time.

Brief Adaptation to Astigmatism Reduces Meridional Anisotropy in Contrast Sensitivity

Purpose

To investigate the effect of visual adaptation to orientation-dependent optical blur on meridional contrast sensitivity function in artificially imposed astigmatism.

Methods

The study adopted a top-up adapt-test paradigm. During the blur adaptation process, the 18 non-astigmatic young adult participants were briefly presented with natural scene images (first trial, 10 minutes; subsequent trials, 6 seconds). Contrast sensitivities for horizontal and vertical gratings at spatial frequencies ranging from 1 to 8 cycles per degree (cpd) were measured immediately before and after adaptation to +3.00 diopters cylinder (DC) with-the-rule or against-the-rule astigmatism. Meridional anisotropy was measured to quantify the contrast sensitivity difference between the two grating orientations.

Results

Adapting to astigmatic blur enhanced contrast sensitivity at the blurred power meridian but reduced contrast sensitivity at the least affected axis meridian. In with-the-rule conditions, contrast sensitivity for horizontal gratings was significantly increased, whereas that for vertical gratings was significantly decreased. Similarly, in against-the-rule conditions, contrast sensitivity for vertical gratings was significantly increased, whereas that for horizontal gratings was significantly decreased. These two factors together resulted in a substantial systematic reduction, averaging 34%, in meridional anisotropy of contrast sensitivity across the spatial frequency spectrum.

Conclusions

Astigmatism adaptation occurs in natural scene viewing. Brief exposure to astigmatic blur altered contrast sensitivity in the opposite direction at the two principal meridians, indicating that the mature visual system possesses functional plasticity to recalibrate the response characteristics of orientationally tuned cortical filters and thus promote substantial reductions of meridional anisotropy in astigmatic vision, to some extent counterbalancing the elongated oval shape of astigmatic blur.

Prevalence of anisometropia and influencing factors among school-age children in Nantong, China: a cross-sectional study

Objective

To investigate the prevalence of anisometropia and associated parameters among school-aged children in Nantong, China.

Methods

This school-based, cross-sectional study examined students from primary schools, junior high schools, and senior high schools in an urban area of Nantong, China. Univariate and multivariate logistic regression analyses were used to investigate the specific correlations between anisometropia and related parameters. Non-cycloplegic autorefraction was assessed for each student. Anisometropia was defined as the spherical equivalent refraction (SE) difference ≥ 1.0 D between eyes.

Results

A total of 9,501 participants were validated for analyses, of which 53.2% (n = 5,054) were male, and 46.8% (n = 4,447) were female. The mean of age was 13.32 ± 3.49 years, ranging from 7-19 years. The overall prevalence of anisometropia was 25.6%. Factors such as myopia, scoliosis screening positive, hyperopia, female sex, older age, and higher weight had a significantly higher risk of anisometropia (p < 0.05).

Conclusion

There was a high prevalence of anisometropia in school-age children. Some physical examination parameters are closely related to children's anisometropia, especially myopia and scoliosis. Preventing myopia and controlling its progression may be the most important ways to reduce the prevalence of anisometropia. Correcting scoliosis may be an important factor in controlling the prevalence of anisometropia, and maintaining good reading and writing posture may be helpful in controlling the prevalence of anisometropia.

A Survey of Myopia Correction Pattern of Children and Parent's Attitudes in China

SIGNIFICANCE

This survey provides information about Chinese children's myopia correction status and parents' attitudes toward myopia correction.

PURPOSE

Under the background of a guideline of appropriate techniques for the prevention and control of children's myopia, this study aimed to investigate the current myopia correction pattern of children and parents' attitudes.

METHODS

Two self-administered questionnaires were distributed to 684 children with myopia corrections and 450 parents (384 mothers and 66 fathers) to explore children's myopia correction patterns and parental attitudes. The questionnaire investigated the pattern of children's myopia correction, prescribing of children's myopia correction, the incidence of high myopia, parental attitudes toward various myopia corrections methods, and preferred initial age for contact lens usage.

RESULTS

Single-vision spectacles (n = 600; 88.2 ± 7.4%) are widely used in China because of their comfort and affordability. More than 80% of children use single-vision spectacles prescribed by ophthalmologists and opticians. Children who used single-vision spectacles at an earlier age had more incidence of high myopia (18.4 ± 4.2%) than those who used single-vision spectacles at a later age (0.7 ± 0.9%). Effective myopia control was the primary reason parents preferred to choose different optical corrections, followed by safety, convenience, clarity, affordability, comfort, and other reasons. The survey indicated that 52.4% of parents whose children used orthokeratology lenses would have preferred safe and convenient options if available. In addition, 50% of the parents preferred delaying their children's use of orthokeratology lenses and other contact lenses to an older age.

CONCLUSIONS

Single-vision spectacles are still a popular option to correct myopia in children. There was a demonstrated increase in myopia in children who used single spectacles at an earlier age. Parents' attitudes were important factors for selecting myopia corrections in children.

Translating and evaluating the Chinese version of Pediatric Eye Questionnaire (PedEyeQ-CN) for children

OBJECTIVES

To investigate the reliability and validity of Chinese version of the Pediatric Eye Questionnaire (PedEyeQ-CN) by testing ophthalmic patients in China.

METHODS

The PedEyeQ (standard English version) was translated by local researchers. Children were asked to complete the Child section, and their parents the Proxy and Parent sections. 160 children (32 normal controls, 77 with refractive error, 48 with strabismus/amblyopia, 3 with other eye conditions) aged 5-11 years old, and one parent of each child were recruited. Cronbach's α and intraclass correlation coefficient were calculated to examine the reliability and test-retest reliability; the score differences between controls and patients were compared to examine the validity.

RESULTS

The internal consistency (Cronbach's α ≥ 0.76) and test-retest reliability (r > 0.80) of PedEyeQ-CN were robust. Children with eye conditions had lower scores compared with children with normal vision (refractive error: 10 out of 13 domains, P ≤ 0.021; strabismus/amblyopia: all domains, P ≤ 0.015). Children with strabismus/amblyopia had lower scores compared with children with refractive error (two domains, P = 0.048, P = 0.001). Visual acuity was significantly correlated with functional vision (P = 0.005), but not significantly correlated with the eye-related quality of life (ER-QOL).

CONCLUSIONS

The PedEyeQ-CN is a valuable tool for assessing the functional vision and ER-QOL of Chinese children and help us increase our understanding about the impact of eye conditions on children and their families.

The Prevalence of Myopia Among Primary School Male Students in Bisha, Saudi Arabia

Background Myopia (shortsightedness) is considered a major health problem globally which has increased in the last few decades. This study aims to determine the prevalence of myopia and the associated risk factors among primary school students in Bisha, Saudi Arabia. Methods This descriptive cross-sectional study included 330 male students from five boys' schools in Bisha city. Students underwent an interview questionnaire that composed of (sociodemographic data, risk factors, and ocular history). Students' vision was assessed by an optometrist through the use of a Snellen chart and the result was converted to a Diopter unit (D). Myopia was defined as the spherical equivalent (SE) of ≤ - 0.5 D. Binomial statistical test was used to get a prevalence of myopia with a confidence interval (CI) of 95%. Chi-square analytical test was used to compare myopic and non-myopic groups on multiple variables. Results were considered statistically significant at p-value ≤ 0.05. Results The mean age of 330 male students was 11.29 ± 0.97. The prevalence of myopia was (32.7%, 95% CI: 27.7-38.1%), and the mean of the SE of participants was - 0.25 ± 0.60 D. Myopia prevalence was increased with age and school grade of participants (p ≤ 0.05). Students who spent a long time (more than three hours) on near activity are at risk of developing myopia (p ≤ 0.001). having one or both parents affected by myopia was not statistically significant with the prevalence of myopia (p = 0.175). Children who spent a long time outdoors tend to have a lower risk of myopia (p ≤ 0.001). Conclusion The study showed a high prevalence of myopia among schoolchildren in Bisha city. Therefore, it is recommended to plan for future screening programs for myopia.

Myopia progression after cessation of low-dose atropine eyedrops treatment: A two-year randomized, double-masked, placebo-controlled, cross-over trial

PURPOSE

The purpose of the study was to evaluate myopia progression and axial elongation after stopping 0.01% atropine eye drops through a 2-year cross-over study.

METHODS

This study was a randomized, double-masked, placebo-controlled, cross-over trial in mainland China. 220 children aged 6-12 years with spherical equivalent range of -1.00 D to -6.00 D in both eyes were enrolled in Phase 1 for 1 year. Children who had completed the first year's follow-up continued in the second phase. In Phase 2, the placebo group was crossed over to the 0.01% atropine group (referred to as the 'placebo-atropine group'), and the 0.01% atropine group was crossed over to the placebo group (referred to as the 'atropine-placebo group'). All children underwent the examination of cycloplegic refraction and axial length at a 6-month interval. Only data from right eyes were included in analysis.

RESULTS

One hundred thirty-three subjects completed 2 years of follow-up. In the first year, the mean myopia progression in atropine-placebo group was 0.21 ± 0.08 D slower than that in placebo-atropine group. After cross-over treatment, the mean myopia progression in atropine-placebo group was 0.22 ± 0.07D faster than that in placebo-atropine group in the second year. Over 2 years, the mean myopia progression was -1.26 ± 0.66D and -1.25 ± 0.70D in the atropine-placebo and placebo-atropine groups (p = 0.954).

CONCLUSIONS

The difference in myopia progression between atropine-placebo group and placebo-atropine group in Phase 1 was similar to Phase 2 during the cross-over treatment. Through our cross-over trial, the results suggest that there is no rebound effect after using 0.01% atropine eye drops to prevent progression of myopia.

Machine Learning-Based Integration of Metabolomics Characterisation Predicts Progression of Myopic Retinopathy in Children and Adolescents

Myopic retinopathy is an important cause of irreversible vision loss and blindness. As metabolomics has recently been successfully applied in myopia research, this study sought to characterize the serum metabolic profile of myopic retinopathy in children and adolescents (4-18 years) and to develop a diagnostic model that combines clinical and metabolic features. We selected clinical and serum metabolic data from children and adolescents at different time points as the training set (n = 516) and the validation set (n = 60). All participants underwent an ophthalmologic examination. Untargeted metabolomics analysis of serum was performed. Three machine learning (ML) models were trained by combining metabolic features and conventional clinical factors that were screened for significance in discrimination. The better-performing model was validated in an independent point-in-time cohort and risk nomograms were developed. Retinopathy was present in 34.2% of participants (n = 185) in the training set, including 109 (28.61%) with mild to moderate myopia. A total of 27 metabolites showed significant variation between groups. After combining Lasso and random forest (RF), 12 modelled metabolites (mainly those involved in energy metabolism) were screened. Both the logistic regression and extreme Gradient Boosting (XGBoost) algorithms showed good discriminatory ability. In the time-validation cohort, logistic regression (AUC 0.842, 95% CI 0.724-0.96) and XGBoost (AUC 0.897, 95% CI 0.807-0.986) also showed good prediction accuracy and had well-fitted calibration curves. Three clinical characteristic coefficients remained significant in the multivariate joint model (p < 0.05), as did 8/12 metabolic characteristic coefficients. Myopic retinopathy may have abnormal energy metabolism. Machine learning models based on metabolic profiles and clinical data demonstrate good predictive performance and facilitate the development of individual interventions for myopia in children and adolescents.

Characteristics of full compensation and its association with total astigmatism: A cross-sectional study

Objective

To evaluate the characteristics of full compensation and its association with the prevalence of total astigmatism (TA), and to analyze the effects of TA on uncorrected distance visual acuity (UDVA).

Methods

With random cluster sampling based on a school-based cross-sectional design, children aged 4 to 18 years were recruited in September 2020, Shandong Province, China. TA, anterior corneal astigmatism (ACA), and ocular residual astigmatism (ORA) were converted to vectorial components (J0, J45), followed by an assessment of the compensatory effect of ACA by ORA. Astigmatism was defined as a cylinder that was better than or equal to 0.75 diopters (D). Logistic regression analysis was used to assess the related factors for children with full compensation, and the generalized linear model was used to assess the influence of TA on UDVA.

Results

Out of 4,494 eligible children, data of 4,145 children (92.3%, 9.23 ± 3.15 years, 50.4% boys) were included in the statistical analysis. The prevalence of TA (27.9%) increased significantly with age (P_trend < 0.001). The distribution of full compensation in J0 and J45 components were similar (22.1% and 25.6%, respectively), which decreased with age (P_trend < 0.001). The closer the refractive status was to emmetropization, the higher the proportion of full compensation and the lower the prevalence of TA were. Shorter axial length (J0: Odds Ratio (OR) = 0.76, 95% confidence interval (CI): 0.61 to 0.94, P = 0.010), better UDVA (J0: OR = 0.37, 95% CI: 0.21 to 0.65, P < 0.001; J45: OR = 0.34, 95% CI: 0.20 to 0.59, P < 0.001), and longer average corneal curvature radius (J0: OR = 3.72, 95% CI: 2.18 to 6.34, P < 0.001; J45: OR = 2.82, 95% CI: 1.67 to 4.76, P < 0.001) were associated with full compensation. Higher TA was associated with a worse UDVA (β = 0.03, 95% CI: 0.02 to 0.04, P < 0.001).

Conclusions

The prevalence of TA gradually increased with age, and showed a U-shaped distribution with increased refraction. Full compensation was associated with smaller TA and better UDVA. This indicated that considering the compensatory effect of ORA is vital for astigmatism correction in clinical work, which may improve the visual quality.

Refractive development I: Biometric changes during emmetropisation

PURPOSE

Although there are many reports on ocular growth, these data are often fragmented into separate parameters or for limited age ranges. This work intends to create an overview of normal eye growth (i.e., in absence of myopisation) for the period before birth until 18 years of age.

METHODS

The data for this analysis were taken from a search of six literature databases using keywords such as "[Parameter] & [age group]", with [Parameter] the ocular parameter under study and [age group] an indication of age. This yielded 34,409 references that, after screening of title, abstract and text, left 294 references with usable data. Where possible, additional parameters were calculated, such as the Bennett crystalline lens power, whole eye power and axial power.

RESULTS

There were 3422 average values for 17 parameters, calculated over a combined total of 679,398 individually measured or calculated values. The age-related change in refractive error was best fitted by a sum of four exponentials (r²  = 0.58), while all other biometric parameters could be fitted well by a sum of two exponentials and a linear term ('bi-exponential function'; r² range: 0.64-0.99). The first exponential of the bi-exponential fits typically reached 95% of its end value before 18 months, suggesting that these reached genetically pre-programmed passive growth. The second exponentials reached this point between 4 years of age for the anterior curvature and well past adulthood for most lenticular dimensions, suggesting that this part represents the active control underlying emmetropisation. The ocular components each have different growth rates, but growth rate changes occur simultaneously at first and then act independently after birth.

CONCLUSIONS

Most biometric parameters grow according to a bi-exponential pattern associated with passive and actively modulated eye growth. This may form an interesting reference to understand myopisation.

Refractive Errors and Their Associated Factors in Schoolchildren: A Structural Equation Modeling

PURPOSE

To determine the prevalence of myopia and hyperopia in Shahroud schoolchildren and their risk factors.

METHODS

Optometric examinations including the measurement of uncorrected and corrected visual acuity as well as non-cycloplegic and cycloplegic refraction using retinoscopy were done for students. Generalized Structural Equation Modeling (GSEM) was used to determine direct and indirect effects of independent variables on myopia and hyperopia.

RESULTS

The data of 5581 students with a mean age of 9.24 ± 1.7 years were used in this study. The prevalence of myopia was 5.0% (95%CI: 4.3-5.7) and the prevalence of hyperopia was 4.8% (95%CI: 4.0 - 5.5) in all schoolchildren. According to the GSEM results, the odds of myopia in rural areas were 0.55 compared to urban areas. A one-unit increase in the ocular AL increased the odds of myopia by 4.91 times. The interaction of sex and age on myopia was significant such that in girls, the odds of myopia increased by 20% for every one-year increase in age while no significant change was seen in boys. A one-unit increase in the ocular AL decreased the odds of hyperopia by 0.49 times. Moreover, the interaction of outdoor activity hours and sex on the prevalence of hyperopia was significant such that increased outdoor activity reduced the odds of hyperopia in girls while no significant correlation was found in boys.

CONCLUSION

Myopia and hyperopia had moderate prevalence. Axial Length had the largest direct association on myopia and hyperopia. Age and outdoor activity had weak associations on refractive errors.

Comparison of Functional Vision and Eye-Related Quality of Life between Myopic Children Treated with Orthokeratology and Single-Vision Spectacles in Southern China

Objective

To compare eye-related quality of life between Chinese children wearing orthokeratology (OK) contact lenses and single-vision spectacles (SVS) using the Pediatric Eye Questionnaire (PedEyeQ) and to evaluate the impact of different myopia correction methods on children and their parents.

Methods

Children aged 12-17 years and their parents/legal guardians were recruited. The children's myopia ranged from -0.50 to -5.00 diopters (D), and their astigmatism was <1.50 D. They had all been wearing OK contact lenses or SVS for at least 12 months. The children completed the Child PedEyeQ. One of their parents (or a legal guardian) completed the Proxy PedEyeQ and the Parent PedEyeQ. Rasch-calibrated PedEyeQ scores were calculated for each domain and were converted to a scale from 0 to 100 for statistical analysis.

Results

A total of 50 children wearing OK contact lenses, 43 children wearing SVS, and their parents/legal guardians completed the questionnaires. The scores of all Child, Proxy, and Parent PedEyeQ domains in the OK contact lens group were higher than those in the SVS group (all P < 0.05). In the mild and moderate myopia subgroups, the Child, Proxy, and Parent PedEyeQ scores in the mild myopia OK contact lens subgroup were higher than those in the mild myopia SVS group (all P < 0.05) except functional vision and bothered by eyes/vision domains for the proxy PedEyeQ. Similarly, the Child, Proxy, and Parent PedEyeQ scores in the moderate myopia OK contact lens subgroup were higher than those in the moderate myopia SVS subgroup (all P < 0.05) except impact on parent and family domain for the parent PedEyeQ. In the subgroup analysis of glasses type, no significant score difference of any Child, Proxy, and Parent PedEyeQ domain was detected between mild and moderate myopia in either the OK contact lens group or the SVS group (all P > 0.05).

Conclusion

Compared with children wearing SVS, children wearing OK contact lenses have better functional vision and eye-related quality of life. Moreover, OK contact lens has a better correction effect, higher acceptance rates, and less impact on parents and families than SVS.

Prevalence of anisometropia and associated factors in Shandong school-aged children

Objective

To investigate anisometropia's prevalence and associated factors in school-aged children.

Methods

A cross-sectional school-based study was conducted in Shandong Province, China, including children aged 4 to 17 from 9 schools. Anisometropia was defined as the differences between the two eyes in spherical equivalent (SE) or cylinder degree of 1.00 diopter (D) or more [SE or cylindrical (CYL) difference ≥ 1.00 D] after cycloplegic autorefraction. The Generalized Linear Model (GLM) was used to analyze the effects of ocular parameters [the differences between eyes in axial length (AL), habitual visual acuity (HVA), and corneal astigmatism (CA)] and lifestyle parameters (time spent indoor near work and outdoor activities) on anisometropia.

Results

Total 4,198 (93.4%) of the 4,494 children were included in the statistical analysis. The mean difference in inter-eye SE was 0.42 ± 0.61 D. The prevalence of anisometropia was 13.2% (95%CI: 12.1 to 14.2%) (SE anisometropia's prevalence:10.3%; CYL anisometropia's prevalence: 4.1%), increased with older age (OR = 1.10, P = 0.002), the worse myopic eye (myopia vs. premyopia, OR = 1.87, P = 0.002), the worse hyperopic eye (hyperopia vs. premyopia, OR = 1.77, P = 0.013), larger difference in inter-eye AL (0.1-0.3 vs. ≤ 0.1, OR = 1.67, P = 0.008; >0.3 vs. ≤ 0.1, OR = 28.61, P < 0.001), HVA (>0.2 vs. ≤ 0.2, OR = 3.01, P < 0.001), CA (OR = 6.24, P < 0.001), the worse stereoacuity (>100 vs. ≤ 100, OR = 1.59, P = 0.001), longer indoor near work time per day on weekends (4-8 vs. <4, OR = 1.41, P = 0.038; ≥8 vs. <4, OR = 1.40, P = 0.131), and shorter outdoor activity time per day on weekdays (≥1 vs. <1, OR = 0.75, P = 0.046) in multivariable analysis. In the SE anisometropia group, the difference in inter-eye AL (>0.3 vs. ≤ 0.1, β: 0.556, 95%CI: 0.050 to 1.063), HVA (>0.2 vs. ≤ 0.2, β: 0.511, 95%CI: 0.312 to 0.710), and CA (β: 0.488, 95%CI: 0.289 to 0.688), stereoacuity (>100 vs. ≤ 100, β: 0.299, 95%CI: 0.110 to 0.488) had a positive impact on the difference in inter-eye SE.

Conclusions

Ocular parameters and lifestyle parameters are associated with the occurrence of anisometropia in children aged 4 to 17 years, including the difference in inter-eye AL, HVA, CA, stereoacuity, indoor near work time, and outdoor activity time. Preventing myopia and early treating anisometropic amblyopia may be effective ways to reduce the prevalence of anisometropia.

Prevalence of refractive error among Chinese preschool children: The Changsha children eye study

Purpose

We aimed to investigate the refractive status and prevalence of refractive error, as well as its characteristics in Chinese preschool children aged 1-6 years old.

Methods

A population-based cross-sectional study-Changsha Children Eye Study (CCES) was conducted. The prevalence of refractive errors among children aged 1-6 years old from 18 community health service centers was surveyed. A handheld child vision screener, Suowei, was used for examination.

Results

A total of 43,105 preschool children were included. The mean spherical equivalent (SE) was 0.42 ± 1.05 D for the right eyes. The mean astigmatism (diopter of cylinder, DC) was -0.83 ± 1.02 D for the right eyes. The magnitude of refractive error was lower in older children, indicating the ongoing of the emmetropization during the 1-6-year-old children. The prevalence of myopia (SE ≤ -1.00 D), hyperopia (SE ≥ +2.00 D) and astigmatism (DC ≥1.50 D) was 2.94, 13.8 and 17.6%, respectively. The prevalence of myopia decreased with the increase of age between the six age groups (P < 0.001). The prevalence of hyperopia was lower in 5-6 years old, whereas, the prevalence of myopia was slightly higher at this period of time. With-the-rule (WTR) astigmatism (+ cylinder axis 90° ± 15°) was the most prevalent type of astigmatism than against-the-rule (ATR) astigmatism (+ cylinder axis 180° ± 15°) and oblique (OBL) astigmatism (X ² = 209.5, P < 0.001). The binary logistic regression model showed that older age and suffering astigmatism were independently associated with the development of myopia. In addition, there was no significant gender difference in the prevalence of myopia, emmetropia, and hyperopia.

Conclusions

Our population-based cross-sectional study investigated the prevalence of myopia, hyperopia, and astigmatism in preschool children aged 1-6 years old. The distribution of the refractive error was disperse in the younger group and gradually turned more centralized in older group. Similar to hyperopia, with age increased, the prevalence of myopia was lower in preschool children younger than 5 years old and then slightly increased at 5-6 years, which may indicate an early sign of myopia in school-age children. Therefore, we emphasize that more attention should be given to the children at this age.

Prevalence of myopia and uncorrected myopia among 721 032 schoolchildren in a city-wide vision screening in southern China: the Shantou Myopia Study

AIMS

To explore the prevalence and risk factors for myopia and uncorrected myopia in schoolchildren in southern China.

METHODS

The government-led Shantou Myopia Study was conducted from September 2020 to June 2021. Non-cycloplegic refraction was performed. Uncorrected visual acuity (UCVA) was measured along with presenting visual acuity if participants wore spectacles. Spherical equivalent refraction (SER) is defined as the spherical dioptres added to half of the cylindrical dioptres. Myopia is defined as SER <-0.50 dioptre with UCVA of <20/20 in at least one eye.

RESULTS

This study enrolled 724 828 schoolchildren (77.8% of all schoolchildren in Shantou) from 901 schools. Data from 721 032 schoolchildren (99.5%) were analysed (mean age 11.53±3.13 years, 6-20 years, 373 230 boys and 347 802 girls). Among them, 373 459 (51.8%) had myopia: 37.1% of 465 696 children in primary schools, 75.4% of 170 164 children in junior high schools and 84.8% of 85 172 children in senior high schools. The prevalence of myopia increases non-linearly with age. Older age, female and urban living environment were independently associated with myopia prevalence and myopic SER. Among the 373 459 children with myopia, 60.0% had no refractive correction: 74.9%, 53.9% and 35.5% in primary, junior high and senior high schools, respectively.

CONCLUSION

The overall prevalence of myopia among schoolchildren in Shantou was 51.8%, higher than the national average in China. The proportion of uncorrected myopia is high, especially in primary schools. Our results indicate the need for public education on eye care among schoolchildren even in a municipal city.

Trends of myopia development among primary and junior school students in the post-COVID-19 epidemic period

Purpose

To investigate the trends of myopia among primary and junior school students in the post-COVID-19 epidemic period.

Method

A prospective of cross-sectional study using spot photoscreenings in 123,538 children among primary and junior school students from 2019 to 2021 was conducted to evaluate the development of myopia in Xuzhou, China in the post-COVID-19 epidemic period. Equivalent refraction and the prevalence of myopia were recorded.

Results

The spherical equivalent refraction of myopia decreased across all grades except grade 1 (0.23 ± 0.56 D in 2019, 0.24 ± 0.63 D in 2020) from 2019 to 2020. However, refraction exhibited a hyperopic shift in 2021 compared to 2020 for grades 1-5 (no significant decreased for grade 4). The prevalence of myopia in all grades increased in 2020 compared to 2019, and the most dramatic changes were observed from grades 2-5 and grades 7-8 (P < 0.05). The changes in myopia prevalence in grades 1-4 were mild, and the reduction in myopia for Grade 5 is significant from 2020 to 2021. Nevertheless, students in grades 6 and 9 exhibited the greatest growth in myopia prevalence (P < 0.01). All grades had higher myopia prevalence in 2021 compared with 2019, except grade 1 (P = 0.25). The prevalence of myopia in girls was higher compared with boys, and the urban myopia prevalence was higher than in rural areas over the 3 years except in 2019 (P = 0.18).

Conclusions

The prevalence of myopia increased during the COVID-19 epidemic. However, the spherical equivalent refraction of lower grade children drifted to hyperopia and the trends of myopia development remained stable in the post-COVID-19 epidemic period. We should be more concerned about the prevalence of myopia in graduating for the primary or junior grades in the future.

Efficacy and Safety of Consecutive Use of 1% and 0.01% Atropine for Myopia Control in Chinese Children: The Atropine for Children and Adolescent Myopia Progression Study

INTRODUCTION

The purpose of this study was to investigate the efficacy and safety of consecutive use of 1% and 0.01% atropine compared with 0.01% atropine alone over 1 year.

METHODS

A total of 207 participants aged 6-12 years with myopia of - 0.50 to - 6.00 D in both eyes were enrolled in this randomized, controlled, non-masked trial and randomly assigned (1:1) to groups A and B. Group A received 1% atropine weekly and were tapered to 0.01% atropine daily at the 6-month visit, and group B received 0.01% atropine daily for 1 year.

RESULTS

Of the 207 participants, 109 were female (52.7%) and the mean (± standard deviation) age was 8.92 ± 1.61 years. Ninety-one participants (87.5%) in group A and 80 participants (77.7%) in group B completed the 1-year treatment. Group A exhibited less refraction progression (- 0.53 ± 0.49 D vs. - 0.74 ± 0.52 D; P = 0.01) and axial elongation (0.26 ± 0.17 mm vs. 0.36 ± 0.21 mm; P < 0.001) over 1 year compared with group B. The changes in refraction (- 0.82 ± 0.45 D vs. - 0.46 ± 0.35 D; P < 0.001) and axial length (0.29 ± 0.12 mm vs. 0.17 ± 0.11 mm; P < 0.001) during the second 6 months in group A were greater than those in group B, with 72.5% of participants presenting refraction rebound. No serious adverse events were reported.

CONCLUSIONS

The 1-year results preliminarily suggest that consecutive use of 1% and 0.01% atropine confers an overall better effect in slowing myopia progression than 0.01% atropine alone, despite myopia rebound after the concentration switch. Both regimens were well tolerated. The long-term efficacy and rebound after the concentration switch and regimen optimization warrant future studies to determine.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov PRS (Registration No. NCT03949101).

Rural-urban differences in prevalence of and risk factors for refractive errors among school children and adolescents aged 6-18 years in Dalian, China

Purpose

To assess the prevalence of refractive errors (REs) in school children aged 6-18 years in urban and rural settings in Dalian, Northeast of China.

Methods

This is a school-based cross-sectional survey using multi-stage randomization technique. Six- to eighteen-year-old school children from elementary schools, junior and senior high schools from a rural area and an urban area in Dalian were included in December 2018. All subjects underwent a comprehensive questionnaire and eye examination.

Results

A total of 4,522 school children with 6-18 years of age were investigated. The age, gender-adjusted prevalence of myopia, and anisometropia were 82.71 and 7.27% among the urban students as compared to 71.76% and 5.41% among the rural ones (OR = 1.80, 95 % CI = 1.53 - 2.11, P < 0.001; OR = 1.29, 95 % CI = 1.00-1.67, P = 0.049), respectively. The hyperopia was less common in urban students than in rural ones (5.63 vs. 10.21%; OR = 0.54, 95 % CI: 0.43-0.67, P < 0.001). However, there was no significant difference in prevalence of astigmatism between urban (46.07%) and rural (44.69%) participants (OR = 0.96, 95 % CI: 0.84-1.10, P = 0.559). The differences on prevalence of REs were attributed to different social-demographic and physiologic factors.

Conclusions

The students from urban settings are more likely to have myopia and anisometropia but less likely to have hyperopia than their rural counterparts. Although considerable attention had been paid to controlling REs, it is necessary to further consider the urban-rural differences in REs.

Temporal and spatial characterization of myopia in China

Purpose

The aim of this study was to characterize the temporal and spatial distribution of myopia among students aged 7-18 years, by analyzing the aggregation area and providing the basis for the prevention and control of myopia in China.

Methods

A database for the spatial analysis of myopia in China during 1995-2014 was established using ArcGIS10.0 software as a platform for data management and presentation. A spatial autocorrelation analysis of myopia was undertaken, and a temporal and spatial scan analysis was performed using SaTScan9.5 software.

Results

Our data demonstrated that the prevalence of myopia in China in 1995, 2000, 2005, 2010, and 2014 was 35.9, 41.5, 48.7, 57.3, and 57.1%, respectively, thus indicating a gradual upward trend. The prevalence of myopia was analyzed in various provinces (municipalities and autonomous regions), and the highest was found in Jiangsu Province, with an average Moran's I index of 0.244295 in China (P ≤ 0.05). According to the local Moran's I autocorrelation analysis, there was a spatial aggregation of myopia prevalence among students in the entire country, with Shandong, Jiangsu, Anhui, and Shanghai being classified as high-high aggregation areas, while Hainan and Guangxi were classified as low-low aggregation areas. In addition, the Getis-Ord General G results of the global hotspot analysis showed a countrywide myopia prevalence index of 0.035020 and a Z score of 1.7959 (P = 0.07251). Because the myopia prevalence correlation difference was not statistically significant, there were no "positive hotspots" or "negative hotspots." The local hotspot analysis shows that Shandong and Jiangsu belong to high-value aggregation areas, while Hainan and Guizhou belong to low-value aggregation areas. Further analysis using time-space scanning showed 15 aggregation regions in five stages, with four aggregation regions having statistically significant differences (P ≤ 0.05). However, the aggregation range has changed over time. Overall, from 1995 to 2014, the aggregation areas for the myopia prevalence in Chinese students have shifted from the northwest, north, and northeast regions to the southeast regions.

Conclusion

Our data demonstrate that, from 1995 to 2014, the prevalence of myopia increased in students aged 7-18 years in China. In addition, the prevalence of myopia is randomly distributed in various provinces (municipalities and autonomous regions) and exhibits spatial aggregation. Also, the gathering area is gradually shifting to the southeast, with the existence of high-risk areas. It is, therefore, necessary to focus on this area and undertake targeted prevention and control measures.

Analysis of Optic Nerve in Adults With Amblyopia Using OCTA

Objective

The aim was to quantify and compare papillary and peripapillary vessel density in amblyopic eyes of adults and age-matched controls.

Methods

This cross-sectional study involved 20 eyes from 10 subjects with anisometropic amblyopia and 12 eyes of 6 age- and gender-matched healthy controls. Optical coherence tomography angiography (OCTA) was performed on all participants. SPSS 20 was used for data analysis.

Results

The mean subject age was 35.7 ± 10.04 years (range 18–47) in the amblyopia group and 34.67 ± 6.92 years (range 23–42) in the control group. The diopter of amblyopia ranges from +3 to +5 ds. The mean inside optic disk capillary vessel density (CVD) was 41.88 ± 6.55% in amblyopic eyes, 49.23 ± 6.55% in fellow eyes, and 50.23 ± 4% in control eyes (p < 0.05). The mean inside optic disk all vessel density (AVD) was 52.97 ± 6.71% in amblyopic eyes, 59.87 ± 4.59% in fellow eyes, and 60.45 ± 2.8% in control eyes (p < 0.05). The amblyopic eye of participants showed a decrease in vessel density in the inside optic disk than in the fellow eyes and healthy subjects.

Conclusion

Our present study revealed lower vessel density inside the optic disc of adult patients with anisometropic amblyopia. However, further studies are really needed to determine the clinical relevance of this finding.

Prevalence of refractive errors in school-going children of Taif region of Saudi Arabia

PURPOSE

To determine the prevalence of refractive errors in the pediatric population in Taif, Saudi Arabia.

METHODS

This cross-sectional study included 7356 eyes of 3678 primary and secondary school children (males = 1837; females = 1841) with a mean age of 11.8 ± 2.2 years (range: 7-18) (males = 11.4 ± 2.0 [range: 8-16]; females = 12.2 ± 2.3 [range: 7-18]). All participants were selected from the school registers. The participants underwent noncycloplegic refraction to determine refractive errors. Students who refused visual acuity assessment or eye examination and were inconsistent in visual acuity assessment were excluded.

RESULTS

The manifest refraction spherical equivalent of the study population was 0.37 ± 1.52 D (range from - 18.4 to 8.8 D) (males = -0.32 ± 1.4 D [range - 15.88-8.8 D]; females = -0.42 ± 1.6 D [range - 18.38-8.0 D]). The overall prevalence of uncorrected refractive errors among school children in this study was 50.91%. The overall distribution of astigmatism (cylinder error of ≥0.50 D) in the current study population was found to be 50.14% (3688/7356 eyes).

CONCLUSION

Nearly half of the study population in this area was affected with at least one type of refractive error. The findings reveal the necessity for implementing timely and sensitive screening programs/methods to identify and correct refractive errors in this age group.

High Prevalence of Astigmatism in Children after School Suspension during the COVID-19 Pandemic Is Associated with Axial Elongation

During the COVID-19 pandemic, the Hong Kong Government enforced a “school from home” policy between February and September 2020. This cross-sectional epidemiological study was conducted to investigate the prevalence of astigmatism and visual habits after the home confinement period. Vision screenings were conducted at three local government-funded primary schools in Hong Kong from October 2020 to December 2020. A total of 418 ethnically Chinese primary school children completed the eye examination and returned questionnaires concerning demographic information and visual habits. It was found that 46.5% (95% CI, 41.7−61.4%) of the children aged 8 to 11 years had astigmatism ≥ 0.75 D, which was predominately With-The-Rule astigmatism. The prevalence of astigmatism reported in these children is generally higher than that of studies conducted before COVID. Compared to their non-astigmatic peers, astigmatic children had a longer axial length (p < 0.001) and engaged in fewer outdoor activities (p = 0.04). Multiple linear regression analyses also revealed significant relationships between axial length and both cylindrical error and J0 astigmatism. Due to the high astigmatism prevalence, there is a pressing need for further studies on the long-term impact of the pandemic on children’s vision.

Beijing Pinggu Childhood Eye Study: The Baseline Refractive Characteristics in 6- to 12-Year-Old Chinese Primary School Students

Purpose

To report the design and baseline data of a 3-year cohort study in Beijing Pinggu District primary school students in China after COVID-19.

Methods

Noncycloplegic and cycloplegic spherical equivalent refraction (SER) were measured, ocular biometry, including the axial length (AL), anterior chamber depth (ACD) and corneal power (CP), were collected before cycloplegia. Corneal radius (CR), AL-to-CR ratio, and lens power (LP) were calculated.

Results

Among the 4,806 (89.1%) eligible students (51.5% male), the prevalence of emmetropia, myopia, mild hyperopia, and mild-to-high hyperopia was 12.8, 30.8, 53.0, and 3.3% after cycloplegia, respectively. Myopia increased from 2.5% in 6- to 71.6% in 12-year-old students, with 9- and 10-year-olds showing the most prominent increases. The median of cycloplegic SER was 0.50 (IQR = 1.63), and the noncycloplegic SER was −0.38 D (IQR = 1.50), which is more negative than the cycloplegic refraction. The mean AL increased with age, from 22.46 ± 0.70 mm to 24.26 ± 1.07 mm. The ACD increased from 3.38 ± 0.28 mm to 3.70 ± 0.30 mm, and the AL-to-CR ratio increased from 2.91 ± 0.08 to 3.12 ± 0.13 between 6- and 12-year-old students. AL, CR and LP explained the SER variance with R² of 86.4% after adjusting the age and gender.

Conclusions and Relevance

The myopia prevalence since emergence of COVID-19 rapidly increased from 6- to 12-year primary school Chinese children, especially after 7 years of age. The non-cycloplegia SER overestimated the prevalence of myopia, and the cycloplegic SER is a more accurate and reliable method to assess the prevalence of refractive status.

Prevalence of Refractive Error in School Children in Suining City of Sichuan Province, China: A School-Based Cross-Sectional Study

Objective

To investigate the prevalence of refractive errors among school children in Suining City, Sichuan Province, and to provide a scientific basis for prevention and control of myopia.

Methods

This was a school-based cross-sectional study. Children aged 6-15 years were selected from kindergartens, primary schools, and middle schools in the urban setting of Suining City. The children underwent ocular examination including measurement of uncorrected visual acuity (UCVA), visual acuity when wearing glasses, and noncycloplegic autorefractometry.

Results

Of the 1200 eligible students, 1138 children (94.8%), 553 of them girls (47.4%), participated. The mean age was 10.64 ± 2.89 years. The prevalence of myopia, hyperopia, astigmatism, and emmetropia was 59.1% (95% confidence interval (CI): 57.6, 60.5), 5.0% (95% CI: 4.7, 6.1), 38.4% (95% CI: 55.5, 58.5), and 25% (95% CI: 23.7, 26.2), respectively. In univariate analysis, the prevalence of myopia was correlated with age, female gender, and learning stage. The prevalence of hyperopia and astigmatism was correlated with age and learning stage. The prevalence of mild myopia, moderate myopia, and high myopia in the 1138 students was 17.7%, 41.4%, and 3.3%, respectively. The prevalence of mild, moderate, and high myopia all increased with age and learning stage. The prevalence of myopia differed by gender. The mean spherical equivalents of the right and left eyes were -1.40 ± 1.99 diopters (D) and -1.29 ± 1.93 D, respectively, and the median values were -0.75 D and -0.6 D, respectively. The mean spherical equivalent increased with age, learning stage, and female gender.

Conclusions

The most common type of refractive error was myopia which was associated with higher age, female gender, and higher learning stage. This study provides new data and recommendations for myopia-control in school-aged children in Sichuan province.

Novel Uses and Challenges of Artificial Intelligence in Diagnosing and Managing Eyes with High Myopia and Pathologic Myopia

Myopia is a global health issue, and the prevalence of high myopia has increased significantly in the past five to six decades. The high incidence of myopia and its vision-threatening course emphasize the need for automated methods to screen for high myopia and its serious form, named pathologic myopia (PM). Artificial intelligence (AI)-based applications have been extensively applied in medicine, and these applications have focused on analyzing ophthalmic images to diagnose the disease and to determine prognosis from these images. However, unlike diseases that mainly show pathologic changes in the fundus, high myopia and PM generate even more data because both the ophthalmic information and morphological changes in the retina and choroid need to be analyzed. In this review, we present how AI techniques have been used to diagnose and manage high myopia, PM, and other ocular diseases and discuss the current capacity of AI in assisting in preventing high myopia.

Near work, screen time, outdoor time and myopia in schoolchildren in the Sunflower Myopia AEEC Consortium

PURPOSE

To examine the association between near work, screen time including TV and outdoor time with myopia in children from the Sunflower Myopia Asian Eye Epidemiology Consortium (AEEC).

METHODS

We analysed AEEC cross-sectional data (12 241 children) on risk factors (near work, screen time including TV and outdoor time) and myopia of six population-based studies (China, Hong Kong and Singapore). Cycloplegic refraction and axial length (AL) measurements were included. Risk factors were determined using questionnaires. Data were pooled from each study, and multivariable regression analysis was performed to evaluate the associations between risks factors and myopia, spherical equivalent (SE) and AL.

RESULTS

Among the included children, 52.1% were boys, 98.1% were Chinese and 69.7% lived in urban areas. Mean±standard deviation (SD) for age was 8.8 ± 2.9 years, for SE was -0.14 ± 1.8 D and for AL was 23.3 ± 1.1 mm. Myopia prevalence was 30.6%. In multivariate analysis, more reading and writing (OR = 1.17; 95% CI, 1.11-1.24), more total near work (OR = 1.05; 95% CI, 1.02-1.09) and less outdoor time (OR = 0.82, 95% CI, 0.75-0.88) were associated with myopia (p's < 0.05). These factors were similarly associated with SE and AL (p's < 0.05), except for total near work and AL (p = 0.15). Screen time including TV was not significantly associated with myopia (p = 0.49), SE (p = 0.49) or AL (p = 0.83).

CONCLUSION

In this study, increased reading and writing and decreased outdoor time were associated with myopia. Screen time may be a surrogate factor of near work or outdoor time, but further research is needed to assess its role as an independent risk factor for myopia.

The change of myopic prevalence in children and adolescents before and after COVID-19 pandemic in Suqian, China

Purpose

The aim of this study was to investigate the change of myopic prevalence in students with different demographic characteristics before and after the COVID-19 pandemic in Suqian, China.

Methods

A retrospective, cross-sectional study was conducted. Student data from 52 schools in 2019 and 2020 were collected from the electronic medical records database through cluster sampling. Ophthalmic examinations were conducted on students from September to December in 2019 and 2020. Measurements of uncorrected visual acuity (UCVA) and noncycloplegic autorefraction were included to obtain the spherical equivalent refraction (SER) and prevalence of myopia. The difference in the rate of myopia and SER of students ages 6 to 18 with various demographic characteristics was compared between the two years.

Results

Records from 118,479 students in 2019 and the 121,881 students in 2020 were obtained. In 2019 and 2020, the prevalence of overall myopia increased from 43.1% to 48.9% (5.8 percentage point), and a substantial shift in myopic rate occurred in grades 4 to 6 (6.9 percentage point). The change in the prevalence of myopia in girls (5.9 percentage point) was approximately equal to that in boys (5.8 percentage point) and it was more common in rural students (5.9 percentage point) than in urban students (5.1 percentage point). The prevalence of low myopia increased more in children, and the prevalence of moderate myopia increased more in adolescents. The mean spherical equivalent refraction (SER) (-1.34±2.03 D) was lower in 2020 than in 2019 (-1.16±1.92 D), while SER decreased mainly at ages 7 to 15. The SER presented myopic status at the age of 9 (-0.55±1.26 D in 2019, -0.71±1.42 D in 2020), and attained moderate myopia at the age of 15 (-3.06±2.41 D in 2019, -3.22±2.40 D in 2020).

Conclusions

After the COVID-19 pandemic, myopia increased in this population with variable rates of increase in different demographic groups. The change of myopia in children was comparatively greater than that in adolescents. Therefore, we should take measures to prevent and control the development of myopia after the COVID-19 pandemic, especially for younger students.

Longitudinal Changes in Refractive Error Among Preschool Children Aged 1–6 Years: The Changsha Children Eye Study

Purpose

To investigate the longitudinal changes in refractive error of preschool children and explore the factors related to these changes and the timing of intervention.

Methods

The refractive data of preschool children aged 1–6 years were collected from 16 community Health Service Centers in Changsha during April 2016 to July 2019 for the retrospective cohort study. The refractive data of each participant was measured with a hand-held vision screener without cycloplegia. A follow-up for all the included participants was performed. The spherical equivalent change was calculated, subsequently, an analysis of risk factors related to the change was performed.

Results

Four thousand nine hundred twenty-one cases were included in the study with the follow-up for 1–2 years. The refractive status was found smoothly changed in 67.8% of children. The overall initial SE was 0.62 ± 1.13 D, and the average SE change was −0.20 ± 1.23 D per year. However, profound myopic shift was observed in 32.2% of children. The change of SE in 3-year-old group is most overt. The proportions of 1–6 years old who showed moderate and severe myopic shift (SE change ≥–1.00 D) were 21.6, 18.9, 28.2, 25.5, 13.4, and 10%, respectively. At the first visit, the younger children with greater hyperopic state exhibited more noticeable myopic shift, no significant difference was found in gender.

Conclusion

The shift from hyperopia to myopia in preschool children is smooth, with −0.20D change on average per year. We suggest that an optometry screening should start at 3-year-old to track children's refractive status. We recommend that preschool children whose SE changes more than −1.00 D per year go to the ophthalmology department for further examination. Our study also found that at the first visit, the younger the child is and the more positive initial SE is, the degree of shift of myopia is greater.

Pathologic myopia: advances in imaging and the potential role of artificial intelligence

Pathologic myopia is a severe form of myopia that can lead to permanent visual impairment. The recent global increase in the prevalence of myopia has been projected to lead to a higher incidence of pathologic myopia in the future. Thus, imaging myopic eyes to detect early pathological changes, or predict myopia progression to allow for early intervention, has become a key priority. Recent advances in optical coherence tomography (OCT) have contributed to the new grading system for myopic maculopathy and myopic traction maculopathy, which may improve phenotyping and thus, clinical management. Widefield fundus and OCT imaging has improved the detection of posterior staphyloma. Non-invasive OCT angiography has enabled depth-resolved imaging for myopic choroidal neovascularisation. Artificial intelligence (AI) has shown great performance in detecting pathologic myopia and the identification of myopia-associated complications. These advances in imaging with adjunctive AI analysis may lead to improvements in monitoring disease progression or guiding treatments. In this review, we provide an update on the classification of pathologic myopia, how imaging has improved clinical evaluation and management of myopia-associated complications, and the recent development of AI algorithms to aid the detection and classification of pathologic myopia.

Exposure to the Life of a School Child Rather Than Age Determines Myopic Shifts in Refraction in School Children

Purpose

The prevalence of myopia increases with both age and grade for children attending school. The current study aimed to distinguish the effects of aging and grade on myopia.

Methods

Grade 1 students (706 at baseline in 2009, mean age 6.56 ± 0.29 years, range 6.00 to 6.99 years old, 55.5% boys) were followed up until 2012. Cycloplegic spherical equivalent (SE) was measured annually.

Results

The sample in a grade was divided into three 4-month age blocks according to their birth month. Within each grade, there were no significant differences in SE between age blocks (all P > 0.05), despite an age range of one year. More myopic SE was observed in the youngest block of grade 2 compared to the oldest block of grade 1 (difference, -0.36 ± 0.08 D; P < 0.001), although age of the two blocks only differed by four months. Similarly, more myopic SE were found in the youngest block in grade 3 than the oldest block in grade 2 (differences, -0.50 ± 0.10 D; P < 0.001) and in the youngest block in grade 4 than the oldest block in grade 3 (differences, -0.82 ± 0.14 D; P < 0.001).

Conclusions

Exposure to schooling, rather than age, appears to be the major driver of refractive development, at least in the early years of schooling. Interventions during this period, involving reductions in educational pressure and increased time outdoors may have major effects on the subsequent development of myopia.

China Turns to School Reform to Control the Myopia Epidemic: A Narrative Review

ABSTRACT

Myopia is now a major public health issue in parts of East and Southeast Asia, including mainland China. In this region, around 80% of students completing 12 years of school education are now myopic, and from 10% to 20% have high myopia in excess of -6D. Interventions to prevent the onset of myopia based on increasing time outdoors have now been implemented at a system-wide scale in Chinese Taipei (Taiwan) and Singapore with some success, but the prevalence of myopia still remains high by international standards. In mainland China, until recently, myopia prevention was largely based on eye exercises, but these have not been sufficient to prevent an epidemic. Control of myopia progression with atropine eye drops has been widely practiced in Singapore and Taiwan, with recent practice concentrating on low-dose concentrations. Orthokeratology has also been widely used across the region. Recent research has produced both contact and spectacle lenses that slow myopia progression by imposing myopic defocus. The new approaches to myopia control are ready for systematic use, which may be facilitated by system-wide screening and referral. In recent years, renewed emphasis has been placed on the prevention of myopia in mainland China by China's President Xi Jinping. In addition to making use of all the measures outlined above, China now seems to be aiming for major reforms to schooling, reducing educational pressures, particularly in the early school years, freeing more time for outdoor play and learning. These new initiatives may be crucial to myopia prevention and control.

Ocular Biometric Characteristics Measured by Swept-Source Optical Coherence Tomography in Individuals Undergoing Cataract Surgery

PURPOSE

To study the distribution of ocular biometric parameters using a swept-source optical coherence tomography (SS-OCT) biometer in adult candidates for cataract surgery.

DESIGN

A retrospective cross-sectional study.

METHODS

This is a single-center analysis of consecutive eyes measured with the IOLMaster 700 SS-OCT biometer at a large tertiary medical center between February 2018 and June 2020.

RESULTS

Three thousand eight hundred thirty-six eyes of 3836 patients were included in the study. The mean ± SD age was 72.3 ± 12.8 years and 53% were female. The mean biometric values were as follows: total corneal power (44.17 ± 1.70 diopters [D]), total corneal astigmatism (TCA; 1.11 ± 0.87 D), mean posterior keratometry (-5.87 ± 0.26 D), posterior corneal astigmatism (-0.26 ± 0.15 D), axial length (AL; 23.95 ± 1.66 mm), anterior chamber depth (ACD; 3.18 ± 0.42 mm), lens thickness (LT; 4.49 ± 0.47 mm), white-to-white distance (WTW; 11.92 ± 0.44 mm), central corneal thickness (CCT; 0.54 ± 0.04 mm), angle alpha (0.49 ± 0.17 mm), and angle kappa (0.34 ± 0.17 mm). There were sex-related differences in all biometric parameters save for LT (P = .440), angle kappa (P = .216), and corneal astigmatism (P = .103). Biometric parameters demonstrated correlations between AL, WTW distance, ACD, and LT (P < .001). Age correlated with all parameters (P < .001) except CCT and posterior keratometry. Angle alpha and angle kappa magnitudes also correlated (P < .001). The prevalence of patients with TCA ≥0.75 D, 1.0 D, and 1.5 D were 59.1%, 43.4%, and 22.6%, respectively.

CONCLUSIONS

Age significantly correlated with most of the biometric parameters and significant differences between sexes were noted. In addition, the high prevalence of TCA and relatively large angle alpha and angle kappa magnitudes were noted among subjects. These data can be relevant in planning local and national health economics.