High prevalence of myopia in children and their parents in Hong Kong Chinese Population: the Hong Kong Children Eye Study

Large-scale study in Chengdu, China: The prevalence of myopia full-correction decreased with increasing myopia in adolescents

Myopia is an increasingly serious health issue among children and adolescents worldwide. This study investigated the situation related to myopia among students in Chengdu, a city in western China, and analyzed the prevalence of myopia spectacle wear and myopia full-correction and their influencing factors to understand the current status of myopia prevention. This school-based cross-sectional study investigated 1582 schools in seven districts of Chengdu City, China, enrolling a total of 417,337 students aged 6-18 years (elementary, middle, and high school) from 2020 to 2022. Examination items included uncorrected visual acuity (UCVA), slit lamp examination and non-cycloplegic autorefraction. Myopia was defined as non-cycloplegic SE ≤ -0.50 D + UCVA> 0 log MAR (age ≥6). The prevalence of myopia spectacle wear is defined as the number of people wearing glasses for myopia/the number of people with myopia (%) within the study population, and myopia full-correction is defined as normal vision after wearing glasses for myopia (≤0 log MAR for 6 years and above). With the support of the government, this programme is conducted 1-2 times a year. Statistical analyses are conducted to determine the association between myopia and various parameters. The average age of the entire survey population was 10.96 ± 3.5 years, and the overall prevalence of myopia was 48.7%, myopia spectacle wear was 65.7%, and myopia full-correction was 50.5%. With increasing age and educational levels, the prevalence of moderate to high myopia, the prevalence of myopia spectacle wear, and the prevalence of myopia full-correction all rise. The prevalence of mild myopia full-correction (46.5%) was higher than that for moderate myopia (47.1%) and even higher than that for high myopia (39.6%). The correct utilization rate of myopic spectacles was 33.17%, increasing with age and education levels, with the highest correct utilization rate of 40.7% among those with moderate myopia. The prevalence of myopia among children and adolescents in Chengdu is relatively low, and the prevalence of myopia spectacle wear and myopia full-correction need to be improved, and it was found that with the increase of myopia, the prevalence of myopia full-correction among adolescents decreased instead.

Advances in myopia control strategies for children

Myopia has long been a global threat to public health. Timely interventions are likely to reduce the risk of vision-threatening complications. There are both established and rapidly evolving therapeutic approaches to slow myopia progression and/or delay its onset. The effective methods for slowing myopia progression include atropine eye-drops, defocus incorporated multiple segments (DIMS) spectacle lenses, spectacle lenses with highly aspherical lenslets target (HALT), diffusion optics technology (DOT) spectacle lenses, red light therapy (RLT), multifocal soft contact lenses and orthokeratology. Among these, 0.05% atropine, HALT lenses, RLT and +3.00 peripheral addition soft contact lenses yield over 60% reduction in myopia progression, whereas DIMS, DOT and MiSight contact lenses demonstrate at least 50% myopia control efficacy. 0.05% atropine demonstrates a more optimal balance of efficacy and safety than 0.01%. The efficacy of 0.01% atropine has not been consistent and requires further validation across diverse ethnicities. Combining atropine 0.01% with orthokeratology or DIMS spectacles yields better outcomes than using these interventions as monotherapies. Increased outdoor time is an effective public health strategy for myopia prevention while recent studies suggest that 0.05% low-concentration atropine and RLT therapy have promising potential as clinical myopia prevention interventions for high-risk groups. Myopia control spectacle lenses, being the least invasive, are safe for long-term use. However, when considering other approaches, it is essential to ensure proper instruction and regular follow-ups to maintain safety and monitor any potential complications. Ultimately, significant advances have been made in myopia control strategies, many of which have shown meaningful clinical outcomes. However, regular use and adequate safety monitoring over extended durations are imperative to foster confidence that can only come from extensive clinical experience.

Peripapillary atrophy area predicts the decrease of macular choroidal thickness in young adults during myopia progression

OBJECTIVE

This study aimed to investigate the influence of peripapillary atrophy (PPA) area and axial elongation on the longitudinal changes in macular choroidal thickness (ChT) in young individuals with myopia.

METHODS AND ANALYSIS

In this longitudinal investigation, 431 eyes-342 categorised as non-high myopia (non-HM) and 89 as HM-were examined for 2 years. Participants were examined with swept-source optical coherence tomography. The macular ChT, PPA area and axial length (AL) were measured at baseline and follow-up visits. Multiple regression analysis was performed to identify factors associated with ChT changes. The areas under the receiver operating characteristic curves were analysed to ascertain the predictive capacity of the PPA area and axial elongation for the reduction in macular ChT.

RESULTS

Initial measurements revealed that the average macular ChT was 240.35±56.15 µm in the non-HM group and 198.43±50.27 µm in the HM group (p<0.001). It was observed that the HM group experienced a significantly greater reduction in average macular ChT (-7.35±11.70 µm) than the non-HM group (-1.85±16.95 µm, p=0.004). Multivariate regression analysis showed that a greater reduction of ChT was associated with baseline PPA area (β=-26.646, p<0.001) and the change in AL (β=-35.230, p<0.001). The combination of the baseline PPA area with the change in AL was found to be effective in predicting the decrease in macular ChT, with an area under the curve of 0.741 (95% CI 0.694 to 0.787).

CONCLUSION

Over 2 years, eyes with HM exhibit a more significant decrease in ChT than those without HM. Combining the baseline PPA area with the change in AL could be used to predict the decrease of macular ChT.

The Current and Future Landscape of the Childhood Myopia Epidemic in China-A Review

Over the last two decades, the prevalence of myopia has gradually increased in China. Numerous epidemiological studies suggest that education and inadequate time spent outdoors are the major causes of the current myopia epidemic. China is one of the few countries that has begun to address the myopia epidemic with a national-level strategy, implementing nationwide education reform, cost-reduction measurements, and dissemination of information on myopia prevention and control. These "natural experiments" will provide insights into areas that may face similar or potential myopia problems.

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.

Five-Year Clinical Trial of the Low-Concentration Atropine for Myopia Progression (LAMP) Study: Phase 4 Report

PURPOSE

To evaluate (1) the long-term efficacy of low-concentration atropine over 5 years, (2) the proportion of children requiring re-treatment and associated factors, and (3) the efficacy of pro re nata (PRN) re-treatment using 0.05% atropine from years 3 to 5.

DESIGN

Randomized, double-masked extended trial.

PARTICIPANTS

Children 4 to 12 years of age originally from the Low-Concentration Atropine for Myopia Progression (LAMP) study.

METHODS

Children 4 to 12 years of age originally from the LAMP study were followed up for 5 years. During the third year, children in each group originally receiving 0.05%, 0.025%, and 0.01% atropine were randomized to continued treatment and treatment cessation. During years 4 and 5, all continued treatment subgroups were switched to 0.05% atropine for continued treatment, whereas all treatment cessation subgroups followed a PRN re-treatment protocol to resume 0.05% atropine for children with myopic progressions of 0.5 diopter (D) or more over 1 year. Generalized estimating equations were used to compare the changes in spherical equivalent (SE) progression and axial length (AL) elongation among groups.

MAIN OUTCOMES MEASURES

(1) Changes in SE and AL in different groups over 5 years, (2) the proportion of children who needed re-treatment, and (3) changes in SE and AL in the continued treatment and PRN re-treatment groups from years 3 to 5.

RESULTS

Two hundred seventy (82.8%) of 326 children (82.5%) from the third year completed 5 years of follow-up. Over 5 years, the cumulative mean SE progressions were -1.34 ± 1.40 D, -1.97 ± 1.03 D, and -2.34 ± 1.71 D for the continued treatment groups with initial 0.05%, 0.025%, and 0.01% atropine, respectively (P = 0.02). Similar trends were observed in AL elongation (P = 0.01). Among the PRN re-treatment group, 87.9% of children (94/107) needed re-treatment. The proportion of re-treatment across all studied concentrations was similar (P = 0.76). The SE progressions for continued treatment and PRN re-treatment groups from years 3 to 5 were -0.97 ± 0.82 D and -1.00 ± 0.74 D (P = 0.55) and the AL elongations were 0.51 ± 0.34 mm and 0.49 ± 0.32 mm (P = 0.84), respectively.

CONCLUSIONS

Over 5 years, the continued 0.05% atropine treatment demonstrated good efficacy for myopia control. Most children needed to restart treatment after atropine cessation at year 3. Restarted treatment with 0.05% atropine achieved similar efficacy as continued treatment. Children should be considered for re-treatment if myopia progresses after treatment cessation.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

New Designs of Spectacle Lenses for the Control of Myopia Progression: A Scoping Review

Myopia control with new designs of spectacle lenses is a flourishing area of research. The present work reviews the effectiveness of new designs (DIMSs, defocus-incorporated multiple segments; CARE, cylindrical annular refractive element; HALs/SALs, highly/slightly aspherical lenslets; DOT, diffusion optics technology) aiming at slowing myopia progression. A search through the PubMed database was conducted for articles published between 1 January 2003 and 28 February 2023. Publications were included if they documented baseline central refraction (SER) and/or axial length (AL) data, and the change in these parameters, in myopic children wearing new designs of spectacle lenses (treatment group) compared to myopic children using single-vision lenses, SVLs (control group). The selection process revealed nine suitable articles. Comparing the mean and standard error values of the treatment and control groups, the highest differences in the change in the SER and AL were -0.80 (1.23) D [95% CI: -1.053 to -0.547; p < 0.001] and 0.35 (0.05) mm [95% CI: 0.252 to 0.448; p < 0.001], respectively; the effect of treatment provided by a HAL design, compared to SVLs, led to a deceleration of 54.8% in the SER and 50.7% in the AL. However, the heterogeneity of the results prevents reaching strong conclusions about the effectiveness of these new designs.

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.

The influence of the environment and lifestyle on myopia

BACKGROUND

Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of myopia during early childhood has heightened the risk of developing high myopia and related sight-threatening eye conditions in adulthood. This surge in myopia rates, occurring within a relatively stable genetic framework, underscores the profound influence of environmental and lifestyle factors on this condition. In this comprehensive narrative review, we shed light on both established and potential environmental and lifestyle contributors that affect the development and progression of myopia.

MAIN BODY

Epidemiological and interventional research has consistently revealed a compelling connection between increased outdoor time and a decreased risk of myopia in children. This protective effect may primarily be attributed to exposure to the characteristics of natural light (i.e., sunlight) and the release of retinal dopamine. Conversely, irrespective of outdoor time, excessive engagement in near work can further worsen the onset of myopia. While the exact mechanisms behind this exacerbation are not fully comprehended, it appears to involve shifts in relative peripheral refraction, the overstimulation of accommodation, or a complex interplay of these factors, leading to issues like retinal image defocus, blur, and chromatic aberration. Other potential factors like the spatial frequency of the visual environment, circadian rhythm, sleep, nutrition, smoking, socio-economic status, and education have debatable independent influences on myopia development.

CONCLUSION

The environment exerts a significant influence on the development and progression of myopia. Improving the modifiable key environmental predictors like time spent outdoors and engagement in near work can prevent or slow the progression of myopia. The intricate connections between lifestyle and environmental factors often obscure research findings, making it challenging to disentangle their individual effects. This complexity underscores the necessity for prospective studies that employ objective assessments, such as quantifying light exposure and near work, among others. These studies are crucial for gaining a more comprehensive understanding of how various environmental factors can be modified to prevent or slow the progression of myopia.

Interocular Symmetry in Retinal Nerve Fiber Layer Thickness in Children: The Hong Kong Children Eye Study

INTRODUCTION

The aim of this work is to determine the interocular differences in peripapillary retinal nerve fiber layer (p-RNFL) thickness and its associations among school children in Hong Kong.

METHODS

We conducted a population-based study including 4034 children aged 6-8 years from the Hong Kong Children Eye Study (HKCES). All participants received comprehensive ocular examinations where p-RNFL thickness was measured using spectral-domain optical coherence tomography (SD-OCT). The degree of symmetry between both eyes was analyzed and represented by intraclass correlation coefficient (ICC) values. Multivariable linear regression analysis was used to investigate the associations between ocular and systemic factors with p-RNFL thickness difference.

RESULTS

The study included 4034 children with a mean age of 7.61 ± 0.98 years. The mean global p-RNFL thickness was 106.60 ± 9.41 μm in right eyes and 105.99 ± 9.30 μm in left eyes. The ICC for global p-RNFL difference was 0.866 (95% CI 0.858-0.873, p < 0.001). The symmetry displayed the largest values in nasal inferior quadrant with the ICC value of 0.736 (95% CI 0.721-0.749); and the smallest degree of symmetry was found to be in the superior temporal quadrant with the ICC value of 0.567 (95% CI 0.546-0.588). Axial length (AL) difference was found to have more pronounced correlation to interocular symmetry in p-RNFL thickness with the coefficient of 0.514 (p < 0.001).

CONCLUSIONS

Normal variation in interocular symmetry exists in children. Our results can contribute to the establishment of a standard reference for interocular differences in OCT parameters in children. The interocular differences in AL should be considered in the interpretation of RNFL symmetry, in terms of identifying children at risk of developing glaucoma or other ocular disorders.

Increase in Bruch's membrane opening minimum rim width with age in healthy children: the Hong Kong Children Eye Study

BACKGROUND/AIMS

To identify normative values and determinants for Bruch's membrane opening (BMO) and the minimum rim width of BMO (BMO-MRW) among healthy children.

METHODS

A population-based cross-sectional study from the Hong Kong Children Eye Study, recruiting 1, 226 children aged 6-8 years. Spherical refractive error, axial length (AL), body mass index and intraocular pressure (IOP) were measured. The optic nerve head and the peripapillary retinal nerve fibre layer (p-RNFL) were imaged through spectral domain-optical coherence tomography, using 24 equally spaced radial B-scans. Global and sectoral BMO-MRW values, BMO area and fovea-to-BMO (FoBMO) angle were calculated. Multiple regression analysis was performed to define the determinants of BMO area and BMO-MRW in relation to demographic and ocular parameters.

RESULTS

The mean values for global BMO-MRW, BMO area and FoBMO angle among children were 345.76±54.08 µm, 2.34±0.49 mm2 and -5.45±4.36°, respectively. Global and sectoral values for BMO-MRW correlated with p-RNFL thickness (r=0.11-0.35, p<0.001). After adjusting for demographic and ocular parameters, global BMO-MRW increased with age (β=6.4, p<0.001) and greater global p-RNFL thickness (β=1.41, p<0.001), but decreased with larger BMO area (β=-47.46, p<0.001) and higher IOP (β=-1.73, p<0.001). Global BMO-MRW did not associate with AL, whereas both BMO area and FoBMO angle associated with AL (β=0.04, p=0.02 and β=0.31, p=0.03, respectively), but not with age.

CONCLUSION

We observed that BMO-MRW increases with age among children. Our results provide normative values and the determinants of BMO parameters among Chinese children.

Size of living space as a moderator for central and peripheral refractions in children

Undesirable living environment may impose risk on myopia development. Furthermore, peripheral refractive error was suggested to contribute to juvenile eye growth modulation. This study aimed to investigate the interaction between peripheral refractive error and living environment in relation to central refractive status in Hong Kong schoolchildren. Central and peripheral refractive errors, axial length (AL), and corneal radius of curvature (CR) were measured in 573 schoolchildren (age 9.5 ± 0.9 years). The AL/CR ratio was used to represent the central refractive status, accounting for non-cycloplegic refraction. The relative peripheral refractive errors (RPRE) up to ± 20° eccentricities were converted into power vectors: spherical-equivalent error (SER) and J₀ astigmatic components and fitted with quadratic equations. The second-order coefficients of SER (a_SER) and J₀ astigmatism (a_J0) and home size reported by parental questionnaires were analyzed to indicate their relationships with AL/CR. Our results showed that children with higher AL/CR lived in smaller homes (p = 0.01) and had a more hyperopic (p < 0.001) but less astigmatic RPRE (p = 0.01). We further analyzed the relationship between AL/CR with RPRE for children living in small (< 300 ft²), moderate (300-600 ft²), and large home sizes (> 600 ft²). Regardless of the home size, a higher AL/CR remained moderately correlated with a more hyperopic a_SER (all p < 0.001). However, a higher AL/CR was associated with a more positive a_J0 only in children living in large homes, and the relationships were not significant for small and moderate home sizes. Linear regression models further indicated that home size was a significant moderator contributing to the relationship between AL/CR and a_J0. In conclusion, our results were consistent with previous studies, showing that children with axial myopia usually lived in smaller homes and had more hyperopic defocus and more positive J₀ astigmatism. However, the relationship between peripheral astigmatism and axial refraction was modulated by the home size of Hong Kong schoolchildren. While peripheral astigmatism is hypothesized as a visual cue for axial refractive development in children, extrinsic environmental factors, such as home size, might interfere with the relationship and dominate refractive development.

Epidemiological investigation of the status of myopia in children and adolescents in Fujian Province in 2020

PURPOSE

The 2020 epidemiological investigation of myopia in children and adolescents in Fujian Province' aimed to provide reference guidelines for the prevention and control of myopia. The purpose of the present study was to address shortfalls in the epidemiological survey of myopia in Fujian and provide a basis for government decision making.

STUDY DESIGN

A cross-sectional and epidemiological investigation METHODS: Based on their levels of economic development and other economic factors, three cities in Fujian Province (Fuzhou, Xiamen, Longyan) were chosen through cluster random sampling and epidemiological investigation. Final analysis included 41,906 cases. Examinations including visual acuity and mydriatic optometry were performed on all subjects.

RESULTS

The overall proportion of myopia was 63.35% in boys and 70.55% in girls living in Fujian in 2020. The proportions of myopia in Xiamen and Longyan were similar; both cities showed a higher proportion of myopic cases than Fuzhou. The proportion of girls with myopia was higher than boys. The proportion of primary and middle school students with myopia was higher in economically developed regions compared with underdeveloped regions. The proportion of urban students with myopia was higher than in suburban students. Analysis showed that the prevalence of myopia increased with age. Interestingly, the prevalence of myopia was higher in children born in June and August than in children born in other months.

CONCLUSION

Children and adolescents in Fujian have a high rate of myopia which increases as the school grade increases. The better the economic conditions are, the higher the myopic rate. In addition, the myopic rate is higher in girls in and students born in June and August. The government, schools, hospitals, and parents should be alerted to this issue and coordinate to control the risk of myopia exacerbation and improve eyesight conditions of students in Fujian Province.

Differential compensatory role of internal astigmatism in school children and adults: The Hong Kong Children Eye Study

BACKGROUND

To compare the prevalence of refractive (RA), corneal (CA), and internal astigmatism (IA) in Hong Kong children and adults and evaluate the role of IA in compensating for total astigmatism and its relations to myopic traits.

METHODS

The Hong Kong Children Eye Study is a population-based cross-sectional study. Totally 3704 school children (mean age 7.5 ± 1.0 years) and 5577 adults (mean age 41.1 ± 7.5 years), who were their parents, were recruited. Cycloplegic and non-cycloplegic refractive cylinders were obtained from children and adults, respectively. Spearman correlation was applied to detect associations between astigmatism, ocular biometrics, refraction, and lens power. Astigmatism compensation factor (CF) was derived from the power vector analysis J0 and J45.

RESULTS

The prevalence of RA (≤-1.0 D), CA (≥+1.0 D) and IA (≥+1.0 D) was 21.9%, 63.9%, and 9.9% in children, and 30.9%, 39.5%, and 23.7% in adults respectively. The mean RA, CA and IA values in children and adults were -0.69 ± 0.66 D, +1.14 ± 0.61 D, +0.62 ± 0.32 D, and -0.80 ± 0.74 D, +0.97 ± 0.69 D, and +0.76 ± 0.43 D, respectively. In adults and children, IA was negatively correlated with axial length (p < 0.0001), but positively correlated with spherical values and equivalent (p < 0.0001), suggesting an association of astigmatism with myopic traits. A greater proportion of children exhibited compensation by IA than adults in J0 (86.6% vs. 66.0%, p < 0.0001) and J45 components (55.5% vs. 41.7%, p < 0.0001).

CONCLUSIONS

Chinese children in Hong Kong exhibit a higher prevalence of RA and CA than in other cities. Children displayed a greater compensation by IA than adults, suggesting an age-related attenuation of IA compensation. IA is associated with myopic traits.

Effect of Myopic Undercorrection on Habitual Reading Distance in Schoolchildren: The Hong Kong Children Eye Study

INTRODUCTION

This study aimed to evaluate the habitual reading distance among non-myopic children and also myopic children with undercorrection and with full correction.

METHODS

This was a population-based cross-sectional study with a total of 2363 children aged 6-8 years who were recruited from the Hong Kong Children Eye Study. Cycloplegic autorefraction, subjective refraction, habitual visual acuity, and best corrected visual acuity were measured. The entire reading process (9 min) was recorded using a hidden video camera placed 5 m away from the reading desk. Reading distances were taken at 6, 7, 8, and 9 min after the child began reading and were measured using a customized computer program developed in MATLAB. The main outcome was the association of habitual reading distances with refraction status. Habitual reading distances of children were documented via video camera footage.

RESULTS

The habitual reading distances of undercorrected myopic children (23.37 ± 4.31 cm) were the shortest when compared to non-myopic children (24.20 ± 4.73 cm, P = 0.002) and fully corrected myopic children (24.81 ± 5.21 cm, P < 0.001), while there was no significant difference between the last two children groups (P = 0.17). A shorter reading distance was associated with myopia (OR 1.67; 95% CI 1.11-2.51; P = 0.013) after adjusting for age, sex, height, near work time, outdoor time, and parental myopia. The association of reading distance with myopia did not hold after undercorrected myopic children were excluded (OR 0.97, 95% CI 0.55-1.73; P = 0.92). A shorter reading distance correlated with poorer vision under habitual correction (β = - 0.003, P < 0.001).

CONCLUSION

A shorter reading distance was present among undercorrected myopic children. Myopia undercorrection is not recommended as a strategy for slowing myopic progression.

Myopia control and prevention: From lifestyle to low-concentration atropine. The 2022 Josh Wallman Memorial Lecture

The purpose of this study was to explore the findings from the Hong Kong Children Eye Study and the Low Concentration Atropine for Myopia Progression (LAMP-1) Study. The incidence of myopia among schoolchildren in Hong Kong more than doubled during the COVID-19 pandemic, with outdoor time decreased significantly and screen time increased. The change in lifestyle during the COVID-19 pandemic aggravated myopia development. Low-concentration atropine (0.05%, 0.025% and 0.01%) is effective in reducing myopia progression with a concentration-related response. This concentration-dependent response was maintained throughout a 3-year follow-up period, and all low concentrations were well tolerated. An age-dependent effect was observed in each treatment group with 0.05%, 0.025% and 0.01% atropine. Younger age was associated with a poor treatment response to low-concentration atropine. Additionally, low-concentration atropine induced choroidal thickening along a concentration-dependent response throughout the treatment period. During the third year, continued atropine treatment achieved a better effect across all concentrations compared with the washout regimen. Stopping treatment at an older age and receiving lower concentration were associated with a smaller rebound effect. However, differences in the rebound effect were clinically small across all the three concentrations studied.

Orthokeratology lenses with increased compression factor (OKIC): A 2-year longitudinal clinical trial for myopia control

PURPOSE

To investigate the effectiveness of orthokeratology (ortho-k) lenses and corneal changes with increased compression factor for myopia control over a 2-year period.

METHODS

Young participants (age: 6-<12 years), with low myopia (0.50-4.00 D) and low astigmatism (≤1.25 D), were recruited and allowed to choose to wear either single-vision spectacles or ortho-k lenses (randomly assigned to compression factor of either 0.75 or 1.75 D). Axial length and cycloplegic refraction were measured at six monthly intervals for two years by a masked examiner. The myopia control effectiveness was determined by axial elongation.

RESULTS

A significant number of control (63 %) dropped out, mainly due to concern about myopia progression (58 %). A total of 75 participants (mean age: 9.3 ± 1.0 years; control: n = 11, ortho-k [0.75 D]: n = 29, ortho-k [1.75 D]: n = 35) completed the study. Considering ortho-k groups only, the mean axial elongation of participants wearing ortho-k lenses of conventional compression factor (0.75 D) and increased compression factor (1.75 D) were 0.53 ± 0.29 and 0.35 ± 0.29 mm, respectively, over the 2-year study period. The between-group differences in corneal health were not significant at all visits.

CONCLUSION

Participants wearing ortho-k lenses of increased compression factor further slowed axial elongation by 34%, when compared with the conventional compression factor without compromising corneal health. Further investigations are warranted to confirm the potential mechanism of an increased compression factor for improved myopia control effectiveness.

Deep learning system to predict the 5-year risk of high myopia using fundus imaging in children

Our study aims to identify children at risk of developing high myopia for timely assessment and intervention, preventing myopia progression and complications in adulthood through the development of a deep learning system (DLS). Using a school-based cohort in Singapore comprising of 998 children (aged 6-12 years old), we train and perform primary validation of the DLS using 7456 baseline fundus images of 1878 eyes; with external validation using an independent test dataset of 821 baseline fundus images of 189 eyes together with clinical data (age, gender, race, parental myopia, and baseline spherical equivalent (SE)). We derive three distinct algorithms - image, clinical and mix (image + clinical) models to predict high myopia development (SE ≤ -6.00 diopter) during teenage years (5 years later, age 11-17). Model performance is evaluated using area under the receiver operating curve (AUC). Our image models (Primary dataset AUC 0.93-0.95; Test dataset 0.91-0.93), clinical models (Primary dataset AUC 0.90-0.97; Test dataset 0.93-0.94) and mixed (image + clinical) models (Primary dataset AUC 0.97; Test dataset 0.97-0.98) achieve clinically acceptable performance. The addition of 1 year SE progression variable has minimal impact on the DLS performance (clinical model AUC 0.98 versus 0.97 in primary dataset, 0.97 versus 0.94 in test dataset; mixed model AUC 0.99 versus 0.97 in primary dataset, 0.95 versus 0.98 in test dataset). Thus, our DLS allows prediction of the development of high myopia by teenage years amongst school-going children. This has potential utility as a clinical-decision support tool to identify "at-risk" children for early intervention.

Are we facing an increasing surgical demand for high myopic traction maculopathies? A 12-year study from Hong Kong

PURPOSE

We aimed to investigate the longitudinal change in the number of surgically operated myopic traction maculopathies (MTM) cases at a tertiary eye centre.

METHODS

A retrospective study of all consecutive cases of surgically operated MTM over 12 years (2009-2020) was conducted in a myopia prevalent region. We compared outcomes among three groups: (1) myopic macular hole (MH), (2) myopic macular hole with retinal detachment (MHRD), and (3) myopic foveoschisis with retinal detachment (MFRD).

RESULTS

Fifty-one cases were included in the study (8 cases of MH, 33 cases of MHRD and 10 cases of MFRD). The overall mean age was 63.8 +/- 8.7 with a female preponderance (2:1). The mean age of the MH group (58.6) was significantly younger than the MHRD group (64.2) and MFRD group (66.6) (p = 0.02). Subgroup analysis using ATN classification did not show its correlation with both visual improvement and anatomical success. When comparing the first 6-year period (2009-2014) with the second 6-year period (2015-2020), there was a significant increase in the number of cases (p = 0.01).

CONCLUSION

We observe an increase in the number of surgically operated MTM. This follows the trend of the global rise in the prevalence of myopia and baby boomers entering retirement.

Cost-effectiveness analysis of myopia management: A systematic review

The rising prevalence of myopia is a major global public health concern. Economic evaluation of myopia interventions is critical for maximizing the benefits of treatment and the healthcare system. This systematic review aimed to evaluate the cost-effectiveness of interventions for treating myopia. Five databases were searched - Embase, Emcare, PubMed, Web of Science, and ProQuest - from inception to July 2022 and a total of 2,099 articles were identified. After careful assessments, 6 studies met the eligibility criteria. The primary outcomes of this systematic review were costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). The secondary outcomes included utility values and net monetary benefits (NMB). One study determined the cost-effectiveness of photorefractive screening plus treatment with 0.01% atropine, 2 studies examined cost-effectiveness of corneal refractive surgery, and 3 studies evaluated cost-effectiveness of commonly used therapies for pathologic myopia. Corneal refractive surgeries included laser in situ keratomileusis (LASIK), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), photorefractive keratectomy (PRK), and small-incision lenticule extraction (SMILE). Interventions for pathologic myopia included ranibizumab, conbercept, and photodynamic therapy (PDT). At an incremental cost of NZ$ 18 (95% CI 15, 20) (US$ 11) per person, photorefractive screening plus 0.01% atropine resulted in an ICER of NZ$ 1,590/QALY (US$ 1,001/QALY) (95% CI NZ$ 1,390, 1,791) for an incremental QALY of 0.0129 (95% CI 0.0127, 0.0131). The cost of refractive surgery in Europe ranged from €3,075 to €3,123 ([US$4,046 to $4,109 - adjusted to 2021 inflation). QALYs associated with these procedures were 23 (FS-LASIK) and 24 (SMILE and PRK) with utility values of 0.8 and ICERs ranging from approximately €14 (US$17)/QALY to €19 (US$23)/QALY. The ICER of LASIK was US$683/diopter gained (inflation-adjusted). The ICER of ranibizumab and PDT were £8,778 (US$12,032)/QALY and US$322,460/QALY respectively, with conbercept yielding a saving of 541,974 RMB (US$80,163)/QALY, respectively. The use of 0.01% atropine and corneal refractive surgery were cost-effective for treating myopia. Treating pathologic myopia with ranibizumab and conbercept were more cost-effective than PDT. Prevention of myopia progression is more cost-effective than treating pathologic myopia.

Increasing prevalence of myopia and the impact of education in primary-school students in Xi'an, north-western of China

Purpose

The present study was performed to detect the prevalence of myopia among primary-school students in Xi'an, north-western of China.

Methods

The present study was a school-based study with students aged from 6 to 13 years old. All the individuals underwent ophthalmological examination and spherical equivalent (SE) of refractive error were measured with non-cycloplegic refraction. Myopia was defined as a SE of ≤ -0.5 diopters (D), and further divided into three stratified groups based on SE: low myopia (≤ -0.5 to >-3.0 D), moderate myopia (≤ -3.0 to >-6.0 D), and high myopia (≤ -6.0 D). Relative risk factors, including age, sex, grade and ethnicity were investigated using questionnaire.

Results

A total of 4,680 individuals were eligible for this survey and 4,654 (99.4% participation rate) were finally included (51.2% boys). The mean age of participants was 8.756 ± 1.727 years. The whole city-level prevalence of total myopia was 57.1% (95% CI: 55.7-58.6%). Additionally, the prevalence of low, moderate, and high myopia was 45.0% (95% CI: 43.5-46.4%), 11.1% (95% CI: 10.2-12.0%), and 1.0% (95% CI: 0.7-1.3%), respectively. Moreover, grade (education level) instead of age, sex and ethnicity was the most essential risk factor for prevalence of overall myopia (OR = 1.844, 95% CI: 1.605-2.119), and an increase of prevalence by 84.4% per grade was seen. Furthermore, similar associations of grade were significant with low myopia (OR = 1.613, 95% CI: 1.385-1.877) and moderate myopia (OR = 2.186, 95% CI: 1.693-2.823), meanwhile, prevalence of low myopia and moderate myopia demonstrated an increase of prevalence by 61.3 and 118.6% per grade, respectively. None of the factors included in the present study was significant risk factor for high myopia.

Conclusions

The present study investigated a non-negligible high prevalence of myopia among primary-school students in Xi'an, north-western of China, and a gradual increasing in proportion with education level.

Myopia incidence and lifestyle changes among school children during the COVID-19 pandemic: a population-based prospective study

BACKGROUND

The impacts of social restrictions for COVID-19 on children's vision and lifestyle remain unknown.

AIMS

To investigate myopia incidence, spherical equivalent refraction (SER) and lifestyle changes among schoolchildren during the COVID-19 pandemic.

METHODS

Two separate longitudinal cohorts of children aged 6-8 years in Hong Kong were included. The COVID-19 cohort was recruited at the beginning of the COVID-19 outbreak, whereas the pre-COVID-19 cohort was recruited before the COVID-19 pandemic. All children received ocular examinations, and answered a standardised questionnaire relating to their lifestyle, including time spent on outdoor activities and near work, both at baseline and at follow-up visits.

RESULTS

A total of 1793 subjects were recruited, of whom 709 children comprised the COVID-19 cohort with 7.89±2.30 months of follow-up, and 1084 children comprised the pre-COVID-19 cohort with 37.54±3.12 months of follow-up. The overall incidence was 19.44% in the COVID-19 cohort, and 36.57% in pre-COVID-19 cohort. During the COVID-19 pandemic, the change in SER and axial length was -0.50±0.51 D and 0.29±0.35 mm, respectively; the time spent on outdoor activities decreased from 1.27±1.12 to 0.41±0.90 hours/day (p<0.001), while screen time increased from 2.45±2.32 to 6.89±4.42 hours/day (p<0.001).

CONCLUSIONS

We showed a potential increase in myopia incidence, significant decrease in outdoor time and increase in screen time among schoolchildren in Hong Kong during the COVID-19 pandemic. Our results serve to warn eye care professionals, and also policy makers, educators and parents, that collective efforts are needed to prevent childhood myopia-a potential public health crisis as a result of COVID-19.

A systematic review of near work and myopia: measurement, relationships, mechanisms and clinical corollaries

After decades of investigation, the role of near work in myopia remains unresolved, with some studies reporting no relationship and others finding the opposite. This systematic review is intended to summarize classic and recent literature investigating near work and the onset and progression of myopia, potential mechanisms and pertinent clinical recommendations. The impact of electronic device use is considered. PubMed and Medline were used to find peer-reviewed cross-sectional and longitudinal studies related to near work and myopia from 1980 to July 2020 using the PRISMA checklist. Studies were chosen using the Joanna Briggs Institute checklist, with a focus on studies with a sample size greater than 50. Studies were independently evaluated; conclusions were drawn per these evaluations. Numerous cross-sectional studies found increased odds ratio of myopia with increased near work. While early longitudinal studies failed to find this relationship, more recent longitudinal studies have found a relationship between myopia and near work. Rather than daily duration of near work, interest has increased regarding absolute working distance and duration of continuous near viewing. Several reports have found that shorter working distances (<30 cm) and continuous near-work activity (>30 min) are risk factors for myopia onset and progression. Novel objective continuously measuring rangefinding devices have been developed to better address these questions. The literature is conflicting, likely due to the subjective and variable nature in which near work has been quantified and a paucity of longitudinal studies. We conclude that more precise objective measures of near viewing behaviour are necessary to make definitive conclusions regarding the relationship between myopia and near work. Focus should shift to utilizing objective and continuously measuring instruments to quantify near-work behaviours in children, followed longitudinally, to understand the complex factors related to near work. A better understanding of the roles of absolute working distance, temporal properties, viewing breaks and electronic device use on myopia development and progression will aid in the development of evidence-based clinical recommendations for behavioural modifications to prevent and slow myopia.

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.

High prevalence of myopia and low hyperopia reserve in 4411 Chinese primary school students and associated risk factors

Purpose

To investigate the prevalence of myopia in Chinese primary school students and their ocular biometrics including axial length (AL), corneal radius of curvature (CRC) and spherical equivalent refraction (SER). To analyze their association with potential myopia risk factors, such as body mass index (BMI), cram school, time of outdoor activity and electronic screen use.

Methods

In this cross-sectional study of 4500 primary school students from 5 schools, participants underwent refraction using non-cycloplegic autorefractor and visual acuity testing. A follow-up study in the same schools was conducted in 2022. Myopia was defined as SER ≤ -0.50 diopter (D) and uncorrected visual acuity (UCVA) < 0.00 logMAR (6/6). Logistic regression models were used to determine factors associated with myopia.

Results

After excluding 389 participants, the overall prevalence of myopia was 33.6%. The prevalence of high myopia was 0.6%. The prevalence of myopia in girls was significantly higher than that in boys (37.6% vs. 30.0%, p < 0.001). The height, weight and BMI were significantly associated with AL (r = 0.471, r = 0.440, r = 0.276, p < 0.001, respectively). AL/CRC ratio was more highly correlated with SER than AL alone. Regression analysis showed that AL/CRC and hyperopia reserve were associated with myopia onset in the subsequent year (F = 201.557, p < 0.001; F = 68.934, p < 0.001). The cut point of hyperopia reserve for myopia in the subsequent year for grade 1 students was + 0.31D. Age (p < 0.001), parental myopia (p = 0.001) and lack of outdoor activity between classes (p = 0.049) were independently associated with higher prevalence rates of myopia.

Conclusion

The prevalence of myopia among Chinese schoolchildren is alarming high. Consistent with previous cross-sectional data, AL/CRC and hyperopia reserve could function as myopia detection indicators. The hyperopia reserve among children aged between 6 ~ 7 years was low. Healthcare providers need to raise parents’ awareness of the importance of regular eye examination and proper optical correction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02436-5.

The Association of Choroidal Thickening by Atropine With Treatment Effects for Myopia: Two-Year Clinical Trial of the Low-concentration Atropine for Myopia Progression (LAMP) Study

PURPOSE

To evaluate longitudinal changes in subfoveal choroidal thickness (SFChT) among children receiving atropine 0.05%, 0.025%, or 0.01% over 2 years and their associations with treatment outcomes in myopia control.

DESIGN

Double-blinded randomized controlled trial.

METHODS

SFChT was measured at 4-month intervals using spectral domain optical coherence tomography. Cycloplegic spherical equivalent (SE), axial length (AL), best-corrected visual acuity, parental SE, outdoor time, near work diopter hours, and treatment compliance were also measured.

RESULTS

314 children were included with qualified choroidal data. The 2-year changes in SFChT from baseline were 21.15 ± 32.99 µm, 3.34 ± 25.30 µm, and -0.30 ± 27.15 µm for the atropine 0.05%, 0.025%, and 0.01% groups, respectively (P < .001). A concentration-dependent response was observed, with thicker choroids at higher atropine concentrations (β = 0.89, P < .001). Mean SFChT thickness significantly increased at 4 months in the atropine 0.025% (P = .001) and 0.05% groups (P < .001) and then remained stable until the end of the second year (P > .05 for all groups). Over 2 years, an increase in SFChT was associated with slower SE progression (β = 0.074, P < .001) and reduced AL elongation (β = -0.045, P < .001). In the mediation analysis, 18.45% of the effect on SE progression from atropine 0.05% was mediated via its choroidal thickening.

CONCLUSIONS

Low concentration atropine induced a choroidal thickening effect along a concentration-dependent response throughout the treatment period. The choroidal thickening was associated with a slower SE progression and AL elongation among all the treatment groups. Choroidal response can be used for assessment of long-term treatment outcomes and as a guide for concentration titrations of atropine.

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.

Associations of Children's Close Reading Distance and Time Spent Indoors with Myopia, Based on Parental Questionnaire

Purpose: To study the association of parents’ reports about their children’s near work and outdoor habits with myopia in their children. Methods: Data from a questionnaire study conducted in 1983 among Finnish schoolchildren were reanalyzed. Vision screening had been performed for all the schoolchildren (n = 4961) in the 1st, 5th, and 8th grades (7-, 11-, and 15-year-olds) in an area of Central Finland. The questionnaire, including information about myopia, was returned by 4305 (86.7%) participants. Items concerned parents’ estimates of their child’s habitual reading distance, time spent indoors as compared with age peers, daily near work, outdoors time, and parents’ myopia. The associations of myopia with these factors were studied. Results: Myopia prevalence in those with a habitual close reading distance vs. others was 14.3% vs. 2.1%, 28.7% vs. 13.1% and 45.8% vs. 24.7% for the 7-, 11- and 15-year-olds (p < 0.001 in all age-groups). Myopia prevalence in children reported by their parents as spending more time indoors than age peers was 10.9% vs. 2.8% (p < 0.001), 25.0% vs. 14.7% (p = 0.004) and 41.9% vs. 25.7% (p < 0.001) in the three age groups. Myopia prevalence among those reported as spending both more time indoors and reading at a close distance vs. others was 44.2% vs. 11.9% (Fisher’s exact t-test, p < 0.001). In the multiple logistic regression models, parental myopia almost doubled the risk of myopia in the 11- and 15-year-olds. ORs (95% CI) for myopia adjusted for parental myopia and sex were for close reading distance 7.381 (4.054−13.440), 2.382 (1.666−3.406), 2.237 (1.498−3.057), (p < 0.001), and for more time spent indoors, 3.692 (1.714−7.954), p = 0.001, 1.861 (1.157−2.992), p = 0.010), 1.700 (1.105−2.615), p = 0.016, in the three age groups. Conclusion: Children, especially 7-year-olds, reported by their parents as having a close reading distance and spending a lot of time indoors were associated with a higher risk for myopia.

A Study on the Design of Vision Protection Products Based on Children’s Visual Fatigue under Online Learning Scenarios

The rate of myopia in children is increasing rapidly under online learning scenarios. One of the important reasons for this is incorrect reading and writing posture. Three screen view parameters (viewing angle, viewing height, and viewing distance) are selected as significant influencing factors and blink rating is used as a sign of visual fatigue through literature analysis to study the influence factors of myopia in children, and their correlation. Children’s visual fatigue is evaluated by subjective evaluation and is recording using an eye tracker for changes in the three factors through online learning scenario simulation experiment. An optimal regression model is constructed that illustrates the relationship between the three variables and the visual fatigue levels. The aim of this study is to confirm the quantitative relationship between the screen view parameters and visual fatigue, and to design a child vision protection product on this basis. The test results show there is a linear positive correlation between the viewing angle, viewing height, and viewing distance. A vision protection device has been designed based on this model and was verified through function prototype testing. The result of this study quantified the relationship among screen view parameters and children’s visual fatigue, which provides a theoretical basis for the design of a children’s visual protection device.

Feasibility and tolerability of ophthalmic virtual reality as a medical communication tool in children and young people

PURPOSE

Virtual reality (VR) can be useful in explaining diseases and complications that affect children in order to improve medical communications with this vulnerable patient group. So far, children and young people's responses to high-end medical VR environments have never been assessed.

METHODS

An unprecedented number of 320 children and young people were given the opportunity to interact with a VR application displaying original ophthalmic volume data via a commercially available tethered head-mounted display (HMD). Participants completed three surveys: demographics and experience with VR, usability and perceived utility of this technology and the Simulator Sickness Questionnaire. The second survey also probed participants for suggestions on improvements and whether this system could be useful for increasing engagement in science.

RESULTS

A total of 206 sets of surveys were received. 165 children and young people (84 female) aged 12-18 years (mean, 15 years) completed surveys that could be used for analysis. 69 participants (47.59%) were VR-naïve, and 76 (52.41%) reported that they had previous VR experience. Results show that VR facilitated understanding of ophthalmological complications and was reasonably tolerated. Lastly, exposure to VR raised children and young people's awareness and interest in science.

CONCLUSIONS

The VR platform used was successfully utilized and was well accepted in children to display and interact with volume-rendered 3D ophthalmological data. Virtual reality (VR) is suitable as a novel image display platform in ophthalmology to engage children and young people.

Correlation of myopia onset and progression with corneal biomechanical parameters in children

BACKGROUND

Recent epidemiological studies have shown that general eye measurement parameters and corneal biomechanical properties can predict the speed of myopic progression in children.

AIM

To investigate the correlation between the onset and progression of myopia and corneal biomechanical parameters in children.

METHODS

The study included 102 cases in the emmetropia group, 207 cases in the myopic group, and 109 cases in the hyperopic group. The correlation between the change in corneal biomechanical indexes and the change in general ocular measurement parameters was analyzed. A one-way ANOVA test compared general ocular measurement and corneal biomechanical parameters. Pearson’s correlation coefficient was analyzed to correlate corneal biomechanical and general ocular measurement parameters.

RESULTS

The general ophthalmometric parameters: Spherical equivalent (SE), intraocular pressure (IOP), and axial length (AL), differed significantly among subjects in myopia, emmetropia, and hyperopic groups. Children’s SE positively correlated with corneal biomechanical parameters: Second velocity of applanation (A2V), peak distance (PD), and deformation amplitude (DA) (P < 0.05), and second applanation length (A2L) (P < 0.05). But it was negatively correlated with PD, DA and integral radius (IR) (P < 0.05). Also, IOP was negatively correlated with A2L and IR (P < 0.05). AL positively correlated with A2V and negatively correlated with second applanation time (A2T), highest concavity, and PD. Central corneal thickness positively correlated with first applanation length, first applanation time, first applanation deformation amplitude, A2V, A2L, A2T, second applanation deformation amplitude, central curvature radius at highest concavity (HCR), PD, DA, IR, ambrosia relational thickness-horizontal, first applanation stiffness parameter, corvis biomechanical index, topographic and biomechanics index and the first velocity of applanation. The general ocular Km in children positively correlated with corneal biomechanical parameters DA and IR and negatively correlated with A2L, HCR, and PD. There was a positive correlation between the general ocular measurement parameters ΔSE and corneal biomechanical parameters ΔA2V and ΔA2L, and a negative correlation with ΔIR. The increase in general ocular measurement parameter ΔKm positively correlated with changes in corneal biomechanical parameters, ΔDA and ΔIR, and negatively correlated with ΔHCR and ΔPD.

CONCLUSION

Myopia development in children was associated with multiple corneal biomechanical parameters.

Thicker Retinal Nerve Fiber Layer with Age among Schoolchildren: The Hong Kong Children Eye Study

This study aims to investigate the effect of age on the peripapillary retinal nerve fiber layer (p-RNFL) thickness among schoolchildren. A total of 4034 children aged 6–8 years old received comprehensive ophthalmological examinations. p-RNFL thickness was measured from a circular scan (⌀ = 3.4 mm) captured using spectral-domain optical coherence tomography (SD-OCT). Associations between p-RNFL thickness with ocular and systemic factors were determined by multivariate linear regression after adjusting potential confounders using generalized estimating equations (GEE). The mean global p-RNFL thickness was 106.60 ± 9.41 μm (range: 72 to 171 μm) in the right eyes, 105.99 ± 9.30 μm (range: 76 to 163 μm) in the left eyes, and 106.29 ± 9.36 μm (range: 72 to 171 μm) across both eyes. Age was positively correlated with p-RNFL after adjusting for axial length (AL) and confounding factors (β = 0.509; p = 0.001). Upon multivariable analysis, AL was positively associated with temporal p-RNFL thickness (β = 3.186, p < 0.001) but negatively with non-temporal p-RNFL thickness (β = (10.003, −2.294), p < 0.001). Sectoral p-RNFL was the thickest in the inferior temporal region (155.12 ± 19.42 μm, range 68 to 271 μm), followed by the superior temporal region (154.67 ± 19.99 μm, range 32 to 177 μm). To conclude, p-RNFL increased significantly with older age among children 6 to 8 years old in a converse trend compared to adults. Our results provide a reference for interpreting OCT information in children and suggest that stable p-RNFL thickness may not indicate a stable disease status in pediatric patients due to the age effects.

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.

Risk Factors for Myopia in 2 Hong Kong School Systems: A Pilot Study

PURPOSE

Myopia has reached "epidemic" proportions, especially in several East Asian countries. Most myopia emerges during childhood, particularly during the school years. The aim of this study was to investigate myopia prevalence and compare risk factors of myopia among Hong Kong Chinese primary school children under 2 different educational systems.

DESIGN

Cross-sectional study.

METHODS

Visual assessments were conducted in 1 government-funded primary school (n = 159) and 1 international school (n = 223) in Hong Kong in September and October 2018, respectively. Measurements were performed on children aged 8 to 10 years old. Noncycloplegic refraction and axial length were measured, respectively. A validated questionnaire focusing on demographic information, nonscreen time (eg, reading and writing on paper materials), screen time (ie, smartphones and tablets usage), time spent on outdoor activities, and other myopia risk factors was completed by parents of participants.

RESULTS

The prevalence of myopia [37.5% vs 12.8%, P < 0.001; spherical equivalent refraction (SER) ≤ -1.00 diopter (D)] and refractive astigmatism [25.0% vs 7.2%, P < 0.001; cylinder (Cyl) ≥ 1.00 diopter cylinder (DC)] were significantly higher in the local school than in the international school. Students in the local school were slightly older than those attending the international school (9.17 ± 0.82 years vs 8.95 ± 0.85 years, P = 0.046), and there was no significant difference in gender distribution between the 2 schools (P = 0.51). There were significant differences in the demographic information including parental myopia (P < 0.001), family income (P < 0.001), and parents' educational level (P < 0.001) between the 2 schools. Multiple regression analysis showed that parental myopia history and continuous near work was associated with myopia in the local school, while the father's educational level was related to myopia in the international school.

CONCLUSIONS

In this pilot study, despite the much higher prevalence of parental myopia and high myopia in the international school, the myopia prevalence among the students is lower in this school than in the local school, suggesting that environmental factors other than genetics might have a stronger protective effect in this school population.

Association of Corneal Biomechanics Properties with Myopia in a Child and a Parent Cohort: Hong Kong Children Eye Study

Associations between corneal biomechanics, axial elongation and myopia are important but previous results are conflicting. Our population-based study aimed to investigate factors associated with corneal biomechanics, and their relationships with myopia in children and adults. Data from 3643 children and 1994 parents showed that children had smaller deformation amplitudes (DA) than parents (p < 0.001). A larger DA was significantly associated with elongated axial length (AL; children: ß = 0.011; adults: ß = 0.0013), higher corneal curvature (children: ß = 0.0086; adults: ß = 0.0096), older age (children: ß = 0.010; adults: ß = 0.0013), and lower intraocular pressure (IOP; children: ß = −0.029; adults: ß = −0.031) in both cohorts. The coefficient of age for DA in children was larger than in adults (p < 0.001), indicating that the DA change with age in children is faster than in adults. DA was significantly associated with spherical equivalent (p < 0.001) resulting from its correlation with AL and corneal curvature. In conclusion, the cornea is more deformable in adults than in children, whereas corneal deformation amplitude increases faster with age in children than that in adults, along with AL elongation. Longer AL, steeper corneal curvature, older age and smaller IOP correspond to a more deformable cornea. The association between corneal deformation amplitude and refraction was mediated via AL and corneal curvature.

Lifestyle modification in school-going children before and after COVID-19 lockdown

Purpose

To evaluate the impact of COVID-19 lockdown restrictions on lifestyle of school-going children.

Methods

This was a questionnaire-based prospective study of 1237 school children aged 9-14 years enrolled from various private and government schools across Delhi in October-December 2020. These children were being followed-up over the previous 2 years (before pandemic) with details of their lifestyle like near/outdoor/reading activities using a questionnaire as a part of another study. The data during the COVID-19 lockdown was collected by telephonic interview. This was compared to similar information collected from this cohort in the pre-Covid period in 2019 when the students had a regular physical school curriculum.

Results

A significant decline was noted in time spent on outdoor activity (from 8.5 hours/week in pre-COVID-19 time to 1.6 hours/week during COVID-19 lockdown; P < 0.001) and doing homework offline (from 15.3 hour/week to 14 hours/week; P < 0.001). A significant increase was noted in screen time spent on digital devices (from 6.2 hours/week to 19.8 hours/week; P<0.001), and watching television (from 12.2 hours/week to 13.4 hours/week; P < 0.001). The rise in the digital on-screen time was significantly more in boys (P < 0.001) and in students from private schools (P < 0.001). The rise in the duration of watching television was significantly more in girls than boys (P < 0.05).

Conclusion

COVID-19 lockdown has markedly impacted the lifestyle of school children by significantly decreasing the outdoor activity and increasing the screen time, thereby pre-disposing them to ocular ill-health and myopia. This necessitates the adoption of guidelines for promoting healthy digital habits in children.

The Prevalence of Myopia in Children in Spain: An Updated Study in 2020

Background: In recent years, there was a significant increase in myopia incidence worldwide. However, it is still not clear how it affects Spanish children. Since 2016, this research team analyzed myopia prevalence and risk in 9668 children aged between 5 and 7 years. It was shown that the prevalence rates increased from 16.8% in 2016 to 20.4% in 2019. The objective of this study is to update the prevalence rate of myopia in Spain in 2020 and analyze the risk and prevention factors of myopia. Methods: The participants underwent an optometric examination, and a questionnaire on their lifestyle, family history, and geographical origin was carried out. Finally, data were analyzed using the SPSS version 27 program. Results: 1601 children from various Autonomous Communities of Spain were examined. In 2020 the myopia rates did not increase compared to 2019 (p < 0.05), although the number of hyperopes decreased and the number of emmetropes increased. Regarding age, the prevalence of myopia increased progressively over the years (p < 0.001). There was no association between gender and myopia (p > 0.05). There was a link between the time spent in near vision and family history with the prevalence of myopia (p < 0.05). Conclusions: The prevalence of myopia in Spain in children between 5 and 7 years old increased significantly between 2016 and 2020.

Prevalence and risk factors for myopia and high myopia: A cross-sectional study among Han and Uyghur students in Xinjiang, China

PURPOSE

This study aimed to investigate the prevalence and risk factors for myopia and high myopia among Han and Uyghur students in Xinjiang, China.

METHODS

This cross-sectional study with a multistage, stratified cluster sampling method was completed in Xinjiang, China. Visual acuity and noncycloplegic refraction were measured. The crude and sex- and age-adjusted prevalence of myopia and high myopia in Han and Uyghur students were compared. Multivariate logistic regression analyses were applied to identify risk factors associated with myopia and high myopia.

RESULTS

In total, 84,033 participants were included in the final analysis, comprising 64,110 Han and 19,923 Uyghur participants. The overall age- and sex-adjusted prevalence of myopia and high myopia were 47.70% (95% CI: 47.67-47.74) and 2.55% (95% CI: 2.54-2.56), respectively. Compared to the Uyghur population, the Han population had a higher prevalence of myopia (63.59% vs. 21.34%, p < 0.0001) and high myopia (4.68% vs. 0.6%, p < 0.0001). Han ethnicity, age, female sex, higher education level and living in urban areas were found to be positively associated with myopia and high myopia. Living in northern Xinjiang was found to be positively associated with myopia but negatively associated with high myopia.

CONCLUSIONS

Our study investigated the prevalence of myopia and high myopia among Han and Uyghur students aged 4-23 years in Xinjiang, China. The Han population had a higher prevalence of myopia and high myopia than the Uyghur population. However, the prevalence of myopia among the Uyghur population showed a more remarkable increasing trend than that among the Han population in Xinjiang.

Delayed Diagnosis of Amblyopia in Children of Lower Socioeconomic Families: The Hong Kong Children Eye Study

AIMS

To determine the prevalence of amblyopia and the factors associated with delayed diagnosis among school-aged children in Hong Kong.

METHODS

Completed comprehensive ophthalmoscopic examinations were conducted among 4.273 children aged 6-8 years in the population-based Hong Kong Children Eye Study. New and previous diagnoses of amblyopia were identified. Socioeconomic status was surveyed through questionnaires.

RESULTS

According to criteria from the Multi-Ethnic Pediatric Eye Disease Study (MEPEDS), amblyopia was present in 43 out of 4,273 children (1.01%; 95% CI, 0.71-1.31). Among them, 33 (0.77%) were newly detected cases that were more likely from families living in Public Rental Housing or subdivided flats (OR, 4.22; P = .012), with lower paternal (OR 6.68, P = .008) and maternal education levels (OR, 4.38; P = .039). Multivariate analysis revealed associations of amblyopia with hyperopia (≥+2.00D; OR, 6.23; 95% CI, 2.86-13.56, P < .001), astigmatism (≥+2.00D; OR, 24.88; 95% CI, 10.69-57.91, P < .001) and anisometropia (≥2.00D; OR, 14.49; 95% CI, 5.93-37.63, P < .001).

CONCLUSION

These children with delayed diagnoses of amblyopia were more likely to come from lower socioeconomic backgrounds. Public education aimed at increasing awareness and utilization of child vision screening among such families is needed.

Three-Year Clinical Trial of Low-Concentration Atropine for Myopia Progression Study: Continued Versus Washout: Phase 3 Report

PURPOSE

(1) To compare the efficacy of continued and stopping treatment for 0.05%, 0.025%, and 0.01% atropine during the third year. (2) To evaluate the efficacy of continued treatment over 3 years. (3) To investigate the rebound phenomenon and its determinants after cessation of treatment.

DESIGN

A randomized, double-masked extended trial.

PARTICIPANTS

A total of 350 of 438 children aged 4 to 12 years originally recruited into the Low-Concentration Atropine for Myopia Progression (LAMP) study.

METHODS

At the beginning of the third year, children in each group were randomized at a 1:1 ratio to continued treatment and washout subgroups. Cycloplegic spherical equivalent (SE) refraction and axial length (AL) were measured at 4-month intervals.

MAIN OUTCOME MEASURES

Changes in SE and AL between groups.

RESULTS

A total of 326 children completed 3 years of follow-up. During the third year, SE progression and AL elongation were faster in the washout subgroups than in the continued treatment groups across all concentrations: -0.68 ± 0.49 diopters (D) versus -0.28 ± 0.42 D (P < 0.001) and 0.33 ± 0.17 mm versus 0.17 ± 0.14 mm (P < 0.001) for the 0.05%; -0.57 ± 0.38 D versus -0.35 ± 0.37 D (P = 0.004) and 0.29 ± 0.14 mm versus 0.20 ± 0.15 mm (P = 0.001) for the 0.025%; -0.56 ± 0.40 D versus -0.38 ± 0.49 D (P = 0.04) and 0.29 ± 0.15 mm versus 0.24 ± 0.18 mm (P = 0.13) for the 0.01%. Over the 3-year period, SE progressions were -0.73 ± 1.04 D, -1.31 ± 0.92 D, and -1.60 ± 1.32 D (P = 0.001) for the 0.05%, 0.025%, and 0.01% groups in the continued treatment subgroups, respectively, and -1.15 ± 1.13 D, -1.47 ± 0.77 D, and -1.81 ± 1.10 D (P = 0.03), respectively, in the washout subgroup. The respective AL elongations were 0.50 ± 0.40 mm, 0.74 ± 0.41 mm, and 0.89 ± 0.53 mm (P < 0.001) for the continued treatment subgroups and 0.70 ± 0.47 mm, 0.82 ± 0.37 mm, and 0.98 ± 0.48 mm (P = 0.04) for the washout subgroup. The rebound SE progressions during washout were concentration dependent, but their differences were clinically small (P = 0.15). Older age and lower concentration were associated with smaller rebound effects in both SE progression (P < 0.001) and AL elongation (P < 0.001).

CONCLUSIONS

During the third year, continued atropine treatment achieved a better effect across all concentrations compared with the washout regimen. 0.05% atropine remained the optimal concentration over 3 years in Chinese children. The differences in rebound effects were clinically small across all 3 studied atropine concentrations. Stopping treatment at an older age and lower concentration are associated with a smaller rebound.

Prevalence of myopia in 3-14-year-old Chinese children: a school-based cross-sectional study in Chengdu

Background

The prevalence of myopia among children in Chengdu is unknown. The aim of this study was to determine the prevalence of myopia in 3- to 14-year-old Chinese children in Chengdu.

Methods

This study was a school-based cross-sectional study in children aged 3–14 years. Visual acuity (VA), spherical equivalent error (SER) with noncycloplegic autorefraction, axial length (AL) and corneal radius (CR) were measured.

Results

A total of 19,455 children were recruited for this study. The prevalence of myopia was 38.1 %; the prevalence of low myopia was 26.6 %, that of moderate myopia was 9.8 %, and that of high myopia was 1.7 %. The prevalence of myopia and SER increased with age from 6 years old. The prevalence of myopia was higher, and the SER indicated more severe myopia in the girls than in the boys (40.1 % vs. 36.2 %, χ² = 30.67, d_f = 1, P < 0.001; -0.93 D ± 1.75 D vs. -0.84 D ± 1.74 D, t = 3.613, d_f=19,453, P < 0.001). The girls had a higher prevalence of myopia and myopic SER than did the boys aged 9 years and older (P < 0.05). Among the myopic children, the rates of uncorrected, undercorrected and fully corrected myopia were 54.8 %, 31.1 and 14.1 %, respectively. AL and AL/CR increased with age from 6 years old, but CR remained stable after 4 years old. The AL was longer, and the CR was flatter in the boys than in the girls aged 3 to 14 years old (P < 0.05).

Conclusions

The prevalence of myopia, AL and AL/CR increased, and the SER became more myopic with age from 6 years old. The girls had a higher prevalence of myopia and myopic SER than did the boys, but the boys had a longer AL, flatter CR and higher AL/CR ratio than did the girls. The rate of uncorrected myopia was very high in the myopic children. More actions need to be taken to decrease the prevalence of myopia, especially uncorrected myopia in children.

Deep-Learning-Based Pre-Diagnosis Assessment Module for Retinal Photographs: A Multicenter Study

Purpose

Artificial intelligence (AI) deep learning (DL) has been shown to have significant potential for eye disease detection and screening on retinal photographs in different clinical settings, particular in primary care. However, an automated pre-diagnosis image assessment is essential to streamline the application of the developed AI-DL algorithms. In this study, we developed and validated a DL-based pre-diagnosis assessment module for retinal photographs, targeting image quality (gradable vs. ungradable), field of view (macula-centered vs. optic-disc-centered), and laterality of the eye (right vs. left).

Methods

A total of 21,348 retinal photographs from 1914 subjects from various clinical settings in Hong Kong, Singapore, and the United Kingdom were used for training, internal validation, and external testing for the DL module, developed by two DL-based algorithms (EfficientNet-B0 and MobileNet-V2).

Results

For image-quality assessment, the pre-diagnosis module achieved area under the receiver operating characteristic curve (AUROC) values of 0.975, 0.999, and 0.987 in the internal validation dataset and the two external testing datasets, respectively. For field-of-view assessment, the module had an AUROC value of 1.000 in all of the datasets. For laterality-of-the-eye assessment, the module had AUROC values of 1.000, 0.999, and 0.985 in the internal validation dataset and the two external testing datasets, respectively.

Conclusions

Our study showed that this three-in-one DL module for assessing image quality, field of view, and laterality of the eye of retinal photographs achieved excellent performance and generalizability across different centers and ethnicities.

Translational Relevance

The proposed DL-based pre-diagnosis module realized accurate and automated assessments of image quality, field of view, and laterality of the eye of retinal photographs, which could be further integrated into AI-based models to improve operational flow for enhancing disease screening and diagnosis.

Artificial intelligence in myopia: current and future trends

PURPOSE OF REVIEW

Myopia is one of the leading causes of visual impairment, with a projected increase in prevalence globally. One potential approach to address myopia and its complications is early detection and treatment. However, current healthcare systems may not be able to cope with the growing burden. Digital technological solutions such as artificial intelligence (AI) have emerged as a potential adjunct for myopia management.

RECENT FINDINGS

There are currently four significant domains of AI in myopia, including machine learning (ML), deep learning (DL), genetics and natural language processing (NLP). ML has been demonstrated to be a useful adjunctive for myopia prediction and biometry for cataract surgery in highly myopic individuals. DL techniques, particularly convoluted neural networks, have been applied to various image-related diagnostic and predictive solutions. Applications of AI in genomics and NLP appear to be at a nascent stage.

SUMMARY

Current AI research is mainly focused on disease classification and prediction in myopia. Through greater collaborative research, we envision AI will play an increasingly critical role in big data analysis by aggregating a greater variety of parameters including genomics and environmental factors. This may enable the development of generalizable adjunctive DL systems that could help realize predictive and individualized precision medicine for myopic patients.

New Polygenic Risk Score to Predict High Myopia in Singapore Chinese Children

Purpose

The purpose of this study was to develop an Asian polygenic risk score (PRS) to predict high myopia (HM) in Chinese children in the Singapore Cohort of Risk factors for Myopia (SCORM) cohort.

Methods

We included children followed from 6 to 11 years old until teenage years (12–18 years old). Cycloplegic autorefraction, ultrasound biometry, Illumina HumanHap 550, or 550 Duo Beadarrays, demographics, and environmental factors data were obtained. The PRS was generated from the Consortium for Refractive Error and Myopia genomewide association study (n = 542,934) and the Strabismus, Amblyopia, and Refractive Error in Singapore children Study (n = 500). The Growing Up in Singapore Towards healthy Outcomes Cohort study (n = 339) was the replication cohort. The outcome was teenage HM (≤ −5.00 D) with predictive performance assessed using the area under the curve (AUC).

Results

Mean baseline age ± SD was 7.85 ± 0.84 (n = 1004) and 571 attended the teenage visit; 23.3% had HM. In multivariate analysis, the PRS was associated with a myopic spherical equivalent with an incremental R² of 0.041 (95% confidence interval [CI] = 0.010, 0.073; P < 0.001). AUC for HM (0.77 [95% CI = 0.71–0.83]) performed better (P = 0.02) with the PRS compared with a model without (0.72 [95% CI = 0.65, 0.78]). Children at the top 25% PRS risk had a 2.34-fold-greater risk of HM (95% CI = 1.53, 3.55; P < 0.001).

Conclusions

The new Asian PRS improved the predictive performance to detect children at risk of HM.

Translational Relevance

Clinicians may use the PRS with other predictive factors to identify high risk children and guide interventions to reduce the risk of HM later in life.

Long-Wavelength-Filtered Light Transiently Inhibits Negative Lens-Induced Axial Eye Growth in the Chick Myopia Model

Purpose

Eye growth and myopia development in chicks, and some other animal models, can be suppressed by rearing under near-monochromatic, short-wavelength blue light. We aimed to determine whether similar effects could be achieved using glass filters that transmit a broader range of short and middle wavelengths.

Methods

On day 6 or 7 post-hatch, 169 chicks were assigned to one of three monocular lens conditions (−10 D, +10 D, plano) and reared for 7 or 10 days under one of four 201-lux lighting conditions: (1) B410 long-wavelength–filtered light, (2) B460 long-wavelength–filtered light, (3) Y48 short-wavelength–filtered light, or (4) HA50 broadband light.

Results

At 7 days, B410 (but not B460) long-wavelength–filtered light had significantly inhibited negative lens induced axial growth relative to Y48 short-wavelength–filtered light (mean difference in experimental eye = −0.249 mm; P = 0.006) and HA50 broadband light (mean difference = −0.139 mm; P = 0.038). B410 filters also inhibited the negative lens-induced increase in vitreous chamber depth relative to all other filter conditions. Corresponding changes in refraction did not occur, and biometric measurements in a separate cohort of chicks suggested that the axial dimension changes were transient and not maintained at 10 days.

Conclusions

Chromatic effects on eye growth can be achieved using filters that transmit a broad range of wavelengths even in the presence of strong cues for myopia development.

Translational Relevance

Broad-wavelength filters that provide a more “naturalistic” visual experience relative to monochromatic light have potential to alter myopia development, although the effects shown here were modest and transient and require exploration in further species.

Prediction of premyopia and myopia in Chinese preschool children: a longitudinal cohort

BACKGROUNDS

Myopia has become a global public health problem. Children with early onset of myopia are at particular risk of complications associated with myopia. Younger children and children with greater initial myopic refractive errors are at a greater risk of myopia progression. Therefore, it is essential to identify subjects at high risk of developing myopia to facilitate myopia prevention in the early stage, especially during the preschool period. The purpose of this study was to determine whether premyopia and myopia in preschool children can be predicted by easily obtainable parameters.

METHODS

Data was collected in a population-based cohort. Comprehensive examinations included height, weight, refraction, axial length (AL), and corneal radius of curvature (CR), with a follow-up of 2 years. Parental myopia history was obtained from a questionnaire. Myopia was defined as spherical equivalent (SE) ≤ - 0.50 D. Premyopia was defined as - 0.50 D < SE ≤ + 0.75 D. Multivariate linear regression models were fitted to determine the associations between these parameters at baseline and future SE. To predict premyopia and myopia, Cox proportional hazard regression analysis coupled with a nomogram was used.

RESULTS

A total of 830 children (433 boys and 397 girls) were included (40.83 ± 3.43 months old at baseline). A significantly negative relationship was observed in the multivariate analysis between baseline AL, AL/CR, two myopic parents, and the future SE after adjusting for age and gender (coefficient = - 0.291, coefficient = - 5.791, coefficient = - 0.273, respectively, both p <  0.001). Higher baseline AL, AL/CR (hazard ratio (HR) = 4.916, HR = 2.979, respectively, comparing the top quartile with the bottom quartile, both p <  0.001) and two myopic parents (HR = 1.756, compared to no myopic parents, p = 0.001) were associated with a higher risk of future onset of premyopia. From the nomogram, AL/CR was found to have the most enormous effect on survival. Different baseline AL and AL/CR values (both Log Rank p <  0.001) had different survival curves.

CONCLUSIONS

AL and AL/CR could be used as obtainable indicators for identifying subjects at high risk of developing premyopia and myopia in young preschool children.

Prevalence of strabismus and its risk factors among school aged children: The Hong Kong Children Eye Study

The study aims to determine the prevalence of strabismus and its risk factors among school children in Hong Kong. This is a cross-sectional study involving 6–8 year old children from different districts in Hong Kong. 4273 children received comprehensive ophthalmological examination, cycloplegic auto-refraction, best corrected visual acuity (BCVA), anterior segment examination, cover/uncover test, ocular motility, and fundus examination. Demographic information, pre- and post- natal background, parental smoking status, and family history of strabismus were obtained through questionnaires. Strabismus was found among 133 children (3.11%, 95% CI 2.59–3.63%), including 117 (2.74%) exotropia and 12 (0.28%) esotropia cases (exotropia-esotropia ratio: 9.75:1). There was no significant difference in prevalence across age (6–8 years) and gender. Multivariate analysis revealed associations of strabismus with myopia (≤ − 1.00D; OR 1.61; 95% CI 1.03–2.52; P = 0.037) hyperopia (≥ + 2.00D; OR 2.49; 95% CI 1.42–4.39; P = 0.002), astigmatism (≥ + 2.00D; OR 2.32; 95% CI 1.36–3.94; P = 0.002), and anisometropia (≥ 2.00D; OR 3.21; 95% CI 1.36–7.55; P = 0.008). Other risk factors for strabismus included maternal smoking during pregnancy (OR 4.21; 95% CI 1.80–9.81; P = 0.001), family history of strabismus (OR 6.36; 95% CI 2.78–14.50, P < 0.0001) and advanced maternal age at childbirth (> 35 years; OR 1.65; CI 1.09–2.49, P = 0.018). The prevalence of strabismus among children aged 6—8 years in Hong Kong is 3.11%. Refractive errors, family history of strabismus and maternal smoking history during pregnancy are risk factors. Early correction of refractive errors and avoidance of maternal smoking during pregnancy are potentially helpful in preventing strabismus.

Comparison of choroidal thickness measurements between spectral domain optical coherence tomography and swept source optical coherence tomography in children

Choroidal thickness is associated with many ocular conditions, interchangeability among different generations of optical coherence tomography is therefore important for both research purpose and clinical application. Hence, we compared choroidal thickness measurements between spectral-domain optical coherence tomography (SD-OCT) and swept-source optical coherence tomography (SS-OCT) in healthy paediatric eyes. A total of 114 children from the population-based Hong Kong Children Eye Study with mean age of 7.38 ± 0.82 years were included. Choroidal thickness of the right eye was measured by both devices. The central foveal choroidal thickness (CFCT) measured by SD-OCT and SS-OCT was 273.24 ± 54.29 μm and 251.84 ± 47.12 μm respectively. Inter-device correlation coefficient was 0.840 (95% CI 0.616–0.918). However, choroidal thickness obtained by SD-OCT was significantly thicker than that measured by SS-OCT with a mean difference of 21.40 ± 33.13 μm (P < 0.001). Bland–Altman limit of agreement on the relative difference scale for SD-OCT/SS-OCT was 86.33 μm. Validated conversion equation for translating SD-OCT CFCT measurement into SS-OCT was SS-OCT = 35.261 + 0.810 × SD-OCT. In conclusion, intra-class correlation coefficient (ICC) shows an acceptable agreement between SD-OCT and SS-OCT, however, there was a significant inter-device difference of choroidal thickness measurements in normal children eyes. Therefore, the measurements are not interchangeable.