Aim To reassess the association between near work, outdoor exposure and myopia in children through an objective approach. Methods Eighty-six children (10.13±0.48 years) were asked to wear Clouclip, a newly developed wearable device that is able to measure working distance and eye-level illuminance, for a complete week to obtain information on near work and outdoor exposure. The mean daily Clouclip wearing time was 11.72±1.14 hour. The spherical equivalent refraction was determined by cycloplegic autorefraction. Results The myopic children were found to be exposed to light intensities >3000 lux (0.68±0.50 hour vs 1.02±0.53 hour, p=0.012) and >5000 lux (0.42±0.35 hour vs 0.63±0.31 hour, p=0.004) for shorter durations on average each day than the non-myopic children. Additionally, the myopic children spent more time on average each day on activities at a distance of 3000 lux (OR=0.27, 95% CI: 0.10 to 0.72, p=0.009); >5000 lux (OR=0.11, 95% CI: 0.02 to 0.56, p=0.008)) and a working distance of 3000 lux (OR=1.17, 95% CI: 1.09 to 1.86, p=0.038) or in that of >5000 lux (OR=1.12, 95% CI: 1.03 to 1.77, p=0.046)) were the independent protective factors and risk factors, respectively. Conclusion The current study provides novel evidence, based on objective data, to support the association between the intensity of near work, light intensity and myopia. However, the causality and the dose-effect relationship need to be investigated further.

Myopia rates have risen in the past decades in China. New strategies for the prevention and control of myopia are now available, and understanding the prevalence and future trends in myopia and high myopia in children and adolescents in China may provide insights into the impact of implementing these measures. The study aims to provide updated data on the prevalence of myopia and high myopia in children and to project temporal trends in prevalence from 2020 to 2050 in China. A systematic review and meta-analysis searching several databases in both English and Chinese: PubMed, Web of Science, Science Direct, China National Knowledge Infrastructure (CNKI), Wanfang, China Science and Technology Journal Database (CSTJ) with date limits from 01/01/2010 to 11/23/2024 was conducted. We included population-based or school-based studies in China that determined the myopia prevalence, based on the cycloplegic refraction, in children under 20. Studies with a response rate <70% or sample size <200 were excluded. A fixed-effect meta-analysis was used, and projections were made based on three scenarios: experience-based, maximum growth (maximum near-work, minimal outdoor time), and minimum growth (2 h outdoor time daily). From 6555 reports, 82 studies with 218,794 participants were included. The overall myopia prevalence was 36.6% (95% CI: 36.4%, 36.8%), with rates of 2.6% in ages 0-4, 22.0% in ages 5-9, 45.4% in ages 10-14, and 67.2% in ages 15-19. High myopia prevalence was 5.3% overall, with rates of 0.1% in ages 0-4, 1.1% in ages 5-9, 3.0% in ages 10-14, and 9.5% in ages 15-19. Projections for 2030 under minimum growth, experience-based, and maximum growth scenarios were 26.8%, 46.2%, 56.0%; 2040 were 19.6%, 54.4%, 65.6%; and 2050 were 14.4%, 61.3%, 71.9%, respectively. China is facing a substantial and potentially worsening epidemic of childhood myopia. This information will provide data for guiding implementation and evaluating the effectiveness of existing and new nationwide myopia prevention and control programs. The Science and Technology Innovation Program of Hunan Province, China (2023RC1079, 2024RC5002).

We investigated the adaptability and acceptance of a novel spectacle lens design that was recently reported to achieve a significant antimyopia effect. A prospective, cross-over study. Twenty children were recruited to wear both Defocus Incorporated Multiple Segments (DIMS) and single vision (SV) lens, with a random assignment of which type of lens was experienced first. For each type of lens, high and low contrast central distant visual acuity (VA) and high contrast mid-peripheral near VA were measured at both 500 lux and 50 lux ambient illuminance after 30 minutes' and a week's wearing of the lens. A self-developed questionnaire was applied to evaluate the visual discomfort at the 1-week visit. All quantitative data were analyzed by paired t test, while qualitative data were analyzed with the χ2 or Wilcoxon signed-rank tests. Central VA was not affected by DIMS lens compared with SV lens in all circumstances (all P > .05). However, the mid-peripheral near VA was found to reduce by approximately 0.06 logarithm of minimal angle of resolution unit in 2 of 4 quadrants (500 lux; P < .05) and in 3 quadrants (50 lux; P < .05) for DIMS lenses. No improvement was detected in the 1-week visit. Mid-peripheral blurred vision was the main visual complaint, which was noticed only once or twice a day. Being aware of the average antimyopic efficacy, 90% of children subjects preferred DIMS lenses. Mid-peripheral vision through DIMS lenses was slightly affected compared with SV lenses. Otherwise, DIMS lenses received good tolerance and acceptance by Chinese children.

To examine the prevalence of refractive errors in children aged 3–6 years in China. Children were recruited for a trial of a home-based amblyopia screening kit in Guangzhou preschools, during which cycloplegic refractions were measured in both eyes of 2480 children. Cycloplegic refraction (from 3 to 4 drops of 1% cyclopentolate to ensure abolition of the light reflex) was measured by both autorefraction and retinoscopy. Refractive errors were defined as followed: myopia (at least −0.50 D in the worse eye), hyperopia (at least +2.00 D in the worse eye) and astigmatism (at least 1.50 D in the worse eye). Different definitions, as specified in the text, were also used to facilitate comparison with other studies. The mean spherical equivalent refractive error was at least +1.22 D for all ages and both genders. The prevalence of myopia for any definition at any age was at most 2.5%, and lower in most cases. In contrast, the prevalence of hyperopia was generally over 20%, and declined slightly with age. The prevalence of astigmatism was between 6% and 11%. There was very little change in refractive error with age over this age range. Previous reports of less hyperopic mean spherical equivalent refractive error, and more myopia and less hyperopia in children of this age may be due to problems with achieving adequate cycloplegia in children with dark irises. Using up to 4 drops of 1% cyclopentolate may be necessary to accurately measure refractive error in paediatric studies of such children. Our results suggest that children from all ethnic groups may follow a similar pattern of early refractive development, with little myopia and a hyperopic mean spherical equivalent over +1.00 D up to the age of 5–6 yearsin most conditions.