Prevalence of Myopia in Children Before, During, and After COVID-19 Restrictions in Hong Kong

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.

Prevalence of visual impairment and estimation of refractive errors among school children in Kakamega, Kenya

AIM

To investigate the prevalence of visual impairment (VI) and provide an estimation of uncorrected refractive errors in school-aged children, conducted by optometry students as a community service.

METHODS

The study was cross-sectional. Totally 3343 participants were included in the study. The initial examination involved assessing the uncorrected distance visual acuity (UDVA) and visual acuity (VA) while using a +2.00 D lens. The inclusion criteria for a subsequent comprehensive cycloplegic eye examination, performed by an optometrist, were as follows: a UDVA<0.6 decimal (0.20 logMAR) and/or a VA with +2.00 D ≥0.8 decimal (0.96 logMAR).

RESULTS

The sample had a mean age of 10.92±2.13y (range 4 to 17y), and 51.3% of the children were female (n=1715). The majority of the children (89.7%) fell within the age range of 8 to 14y. Among the ethnic groups, the highest representation was from the Luhya group (60.6%) followed by Luo (20.4%). Mean logMAR UDVA choosing the best eye for each student was 0.29±0.17 (range 1.70 to 0.22). Out of the total, 246 participants (7.4%) had a full eye examination. The estimated prevalence of myopia (defined as spherical equivalent ≤-0.5 D) was found to be 1.45% of the total sample. While around 0.18% of the total sample had hyperopia value exceeding +1.75 D. Refractive astigmatism (cil<-0.75 D) was found in 0.21% (7/3343) of the children. The VI prevalence was 1.26% of the total sample. Among our cases of VI, 76.2% could be attributed to uncorrected refractive error. Amblyopia was detected in 0.66% (22/3343) of the screened children. There was no statistically significant correlation observed between age or gender and refractive values.

CONCLUSION

The primary cause of VI is determined to be uncorrected refractive errors, with myopia being the most prevalent refractive error observed. These findings underscore the significance of early identification and correction of refractive errors in school-aged children as a means to alleviate the impact of VI.

Predicting the onset of myopia in children by age, sex, and ethnicity: Results from the CLEERE Study

SIGNIFICANCE

Clinicians and researchers would benefit from being able to predict the onset of myopia for an individual child. This report provides a model for calculating the probability of myopia onset, year-by-year and cumulatively, based on results from the largest, most ethnically diverse study of myopia onset in the United States.

PURPOSE

This study aimed to model the probability of the onset of myopia in previously nonmyopic school-aged children.

METHODS

Children aged 6 years to less than 14 years of age at baseline participating in the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) Study who were nonmyopic and less hyperopic than +3.00 D (spherical equivalent) were followed up for 1 to 7 years through eighth grade. Annual measurements included cycloplegic autorefraction, keratometry, ultrasound axial dimensions, and parental report of children's near work and time spent in outdoor and/or sports activities. The onset of myopia was defined as the first visit with at least -0.75 D of myopia in each principal meridian. The predictive model was built using discrete time survival analysis and evaluated with C statistics.

RESULTS

The model of the probability of the onset of myopia included cycloplegic spherical equivalent refractive error, the horizontal/vertical component of astigmatism (J0), age, sex, and race/ethnicity. Onset of myopia was more likely with lower amounts of hyperopia and less positive/more negative values of J0. Younger Asian American females had the highest eventual probability of onset, whereas older White males had the lowest. Model performance increased with older baseline age, with C statistics ranging from 0.83 at 6 years of age to 0.92 at 13 years.

CONCLUSIONS

The probability of the onset of myopia can be estimated for children in the major racial/ethnic groups within the United States on a year-by-year and cumulative basis up to age 14 years based on a simple set of refractive error and demographic variables.

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.

The effects of physical activity on pediatric eyes: A systematic review and meta-analysis

INTRODUCTION

Examining the retina represents a non-invasive method to evaluate abnormalities pertaining to the nervous and cardiovascular systems. Evidence indicates that physical activity is a non-pharmacological intervention to enhance the nervous and cardiovascular systems. However, little is unknown about its effects on ocular characteristics in children and adolescents. The purpose of this study was to examine the effects of physical activity interventions on ocular characteristics in children and adolescents.

METHOD

The electronic bases Web of Science, Embase, Cochrane Library, PubMed, SPORTDiscus, CINAHL, and ERIC were searched from inception to May 2023. Incorporated were randomized controlled trials or quasi-experimental designs that had implemented acute or chronic physical activity interventions among children and adolescents to evaluate various eye-related attributes via clinical examinations or surveys. Two authors independently performed the data extraction and risk of bias assessment, utilizing the Physiotherapy Evidence Database checklist.

RESULTS

A total of 474 articles were identified, of which eight articles underwent a systematic review, and six were chosen for meta-analysis. Chronic physical activity interventions positively impacted central retinal artery equivalent (CRAE) with a small to moderate effect (SMD = 0.21; 95% CI 0.04 to 0.39, p = 0.034, I2 = 0%) and central retinal venular equivalent (CRVE) with a small effect (SMD = 0.098; 95% CI 0.08 to 0.11; p = 0.008, I2 = 0%). Intraocular pressure, kinetic visual acuity, and eye strain also improved significantly after physical activity interventions.

DISCUSSION

Participating in chronic physical activity programs appear to impact children and adolescents' eye-related attributes positively.

COVID-19 and children's eyes

Letter

Compensatory Interactions between Corneal and Internal Astigmatism despite Lifestyle Changes

This study explores whether children's refractive errors and visual behaviors reverted to pre-COVID-19 levels a year after normal schooling resumed in Hong Kong as well as the impact of corneal and internal astigmatism on refractive astigmatism development. Vision survey data and questionnaire results collected in 2022 (n = 119) and 2020 (n = 173) were compared. Cross-sectional data showed similar proportions of astigmatism (cylindrical power ≥ 0.75 D) in the 2020 (49.1%) and 2022 cohorts (55.5%). Despite a 0.28 D increase in corneal astigmatism, a compensatory 0.24 D increase in internal astigmatism of opposite direction kept refractive astigmatism relatively stable. The questionnaire data showed that children spent an additional 0.5 h/day outdoors on weekends post-resumption of normal schooling but engaged in more near-work activities, especially non-screen near-work, by approximately 1 h/day on both weekdays and weekends. These findings were supported by longitudinal data from 72 children who participated in both surveys. This study highlights the significant role of corneal and internal astigmatism in refractive astigmatism changes. Despite the return to in-person classes, children's total near-work time increased and astigmatism remained high. These findings underscore the need for comprehensive strategies to reduce the high environmental risks for refractive error development in children.

Associations of Near Work, Time Outdoors, and Sleep Duration With Myopic Regression 5 Years After SMILE and FS-LASIK: A Cross-sectional Study

PURPOSE

To investigate the association of near work, time outdoors, and sleep duration with myopic regression 5 years after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) .

METHODS

This cross-sectional study included patients who received SMILE or FS-LASIK at Beijing Tongren Hospital 5 years ago. The patients underwent ophthalmic examinations including visual acuity, intraocular pressure, subjective refraction, slit-lamp examination, keratometry, corneal topography, optical coherence tomography, and fundus examination from January 2020 to March 2023. Fluorescein break-up time was measured and the Ocular Surface Disease Index questionnaire was completed to exclude dry eye. A self-administered questionnaire was used to collect data on near work exposure, physical activities, and sleep duration.

RESULTS

A total of 323 eyes were included in the analysis, with a 5-year incidence rate of myopic regression after SMILE or FSLASIK of 16.1%. After adjusted for all confounders, total near work more than 8 hours/day revealed a significant association with myopic regression (odds ratio: 2.461; 95% CI: 1.143 to 5.298, P = .021), particularly in younger adults, women, and patients with high myopia and FS-LASIK treatment. The significant association between sleep duration 8 hours/day or more and myopic regression was restricted to women and patients with FS-LASIK (near significant). However, no significant associations were observed between continuous near work or time outdoors and myopic regression.

CONCLUSIONS

Excessive near work exposure was associated with greater myopic regression 5 years after SMILE or FS-LASIK. It is crucial to maintain good visual behavior and care for preventing regression after SMILE or FS-LASIK, especially for younger patients and eyes with high myopia. [J Refract Surg. 2024;40(1):e10-e19.].

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.

Comparison of myopia progression among Chinese schoolchildren before and during COVID-19 pandemic: a meta-analysis

AIM

To compare myopia progression in Chinese schoolchildren before and after the COVID-19 pandemic home confinement.

METHODS

This study was done through the data searched from PubMed, Embase, Cochrane Library, and Web of Science from January 2022 to March 2023 related to the COVID-19 pandemic home confinement and myopia progression among Chinese schoolchildren. Myopia progression was evaluated by the mean change of spherical equivalent refraction (SER) and axial length (AL) before and during the COVID-19 pandemic. Sex and regional differences in myopia progression among schoolchildren before and during the COVID-19 pandemic were also analyzed.

RESULTS

A total of eight eligible studies were included in this study. There was a significant difference in SER before and during home confinement during the COVID-19 pandemic (OR = 0.34; 95%CI = [0.23, 0.44]; Z = 6.39; P < 0.00001), but no significant difference in AL (OR = 0.16; 95%CI = [- 0.09, 0.41]; Z = 1.22, P = 0.22). There was a significant difference in SER between male and female groups during the COVID-19 home confinement (OR = 0.10; 95%CI = [0.00, 0.19]; Z = 1.98, P = 0.05). As for regional analysis, there was a significant difference in SER between urban and rural areas during the COVID-19 quarantine period (OR = -0.56; 95%CI = [- 0.88, - 0.25]; Z = 3.50, P = 0.0005).

CONCLUSIONS

Compared with the time before the COVID-19 home confinement, a higher rate of myopic progression among Chinese schoolchildren during the period of the COVID-19 pandemic was demonstrated.

Advances in myopia prevention strategies for school-aged children: a comprehensive review

Myopia has significantly risen in East and Southeast Asia, and the pathological outcomes of this condition, such as myopic maculopathy and optic neuropathy linked to high myopia, have emerged as leading causes of irreversible vision loss. Addressing this issue requires strategies to reduce myopia prevalence and prevent progression to high myopia. Encouraging outdoor activities for schoolchildren and reducing near-work and screen time can effectively prevent myopia development, offering a safe intervention that promotes healthier habits. Several clinical approaches can be employed to decelerate myopia progression, such as administering low-dose atropine eye drops (0.05%), utilizing orthokeratology lenses, implementing soft contact lenses equipped with myopia control features, and incorporating spectacle lenses with aspherical lenslets. When choosing an appropriate strategy, factors such as age, ethnicity, and the rate of myopia progression should be considered. However, some treatments may encounter obstacles such as adverse side effects, high costs, complex procedures, or limited effectiveness. Presently, low-dose atropine (0.05%), soft contact lenses with myopia control features, and orthokeratology lenses appear as promising options for managing myopia. The measures mentioned above are not necessarily mutually exclusive, and researchers are increasingly exploring their combined effects. By advocating for a personalized approach based on individual risk factors and the unique needs of each child, this review aims to contribute to the development of targeted and effective myopia prevention strategies, thereby minimizing the impact of myopia and its related complications among school-aged children in affected regions.