IMPORTANCE Myopia has reached epidemic levels among children in regions of East and Southeast Asia. High myopia is associated with myopic macular degeneration, glaucoma, and retinal detachment.OBJECTIVE To determine the incidence of myopia and high myopia based on refraction without cycloplegia among children in primary and junior high schools in China. DESIGN, SETTING, AND PARTICIPANTSThis observational cohort study was completed in Guangzhou, China. It consisted of a cohort from 19 primary schools, who were followed up from 2010 to 2015, and a cohort from 22 junior high schools, who were followed up from 2010 to 2012. All schools were randomly chosen at rates proportional to the number of schools in each of the city's 11 districts. Students with or without myopia in grade 1 (primary school) or grade 7 (junior high school) were eligible for inclusion. Data analysis occurred from February 2017 to October 2017. MAIN OUTCOMES AND MEASURESMyopia was defined as a spherical equivalent refraction (SER) of −0.50 diopters (D) or less, as measured by subjective refraction without cycloplegia; high myopia was defined as a SER of −6.0 D or less. Annual incidences were defined as the proportion of participants each year found to have myopia or high myopia who did not previously have the condition. Height, weight, axial length (AL), corneal radius of curvature (CRC), and AL/CRC ratio were examined to assess if these measures were associated with future myopia or high myopia.RESULTS A total of 4741 students with or without myopia in either grade 1 for the primary school cohort (mean [SD] age 7.2 [0.4] years; 932 of 1975 [47.2%] female) or grade 7 for the junior high school cohort (mean [SD] age 13.2 [0.5] years; 1254 of 2670 [47.0%] female) were included. Baseline mean (SD) SER was 0.31 (0.86) D among 1975 students in grade 1 vs −1.60 (2.00) D among 2670 students in grade 7. Baseline prevalence of myopia was 12.0% in grade 1 students (n = 237 of 1969) and 67.4% in grade 7 students (n = 1795 of 2663). The incidence of myopia was 20% to 30% each year throughout both cohorts. The incidence of high myopia was initially less than 1% in the primary school cohort (grade 1: n = 2 of 1825; 0.1% [95% CI, 0.0%-0.3%]), but incidence exceeded 2% in the junior high school cohort (in grade 9: n = 48 of 2044; 2.3% [95% CI, 1.0%-3.7%]). CONCLUSIONS AND RELEVANCEThe incidence of myopia among Chinese students based on refraction without cycloplegia is among the highest of any cultural or ethnic group. If confirmed with cycloplegic refraction, interventions to prevent myopia onset in Chinese populations should be initiated in primary schools.

Purpose To describe the development and validation of a smartphone-based visual acuity (VA) test called Vision at home (V@home). Methods Three study populations (elderly Chinese, adolescent Chinese, and Australian groups) underwent distance and near VA testing using standard Early Treatment Diabetic Retinopathy Study (ETDRS) charts and the V@home device; all VA tests used tumbling E optotypes. VA tests were repeated with one eye, selected randomly. Distance VA was measured monocularly at 2 m, and near VA was measured binocularly at 40 cm. Participants also completed a questionnaire about their satisfaction with the device. V@home VA (logMAR) was compared to VA for ETDRS charts at distance and near and test-retest reliability. Results The mean difference between V@home and ETDRS distance VA across all groups ranged from −0.010 to −0.100 logMAR. Tolerant weighted kappa (TWK) agreement ranged from substantial (0.742) in the Australian group to almost perfect (0.950) in the adolescent Chinese group. There was high agreement of V@home with near ETDRS VA across all groups, with a mean difference of −0.092 to −0.042 logMAR and a TWK of 0.736 to 0.837. Test-retest reliability was also high (difference: −0.018 to 0.026) for both distance and near VA tests (95% limits of agreement: −0.289 to 0.258 for distance and −0.235 to 0.199 for near). The majority of participants were satisfied with V@home. Conclusions V@home could accurately and reliably measure both distance and near VA and is well accepted by participants. Translational Relevance The V@home system could potentially serve as a useful tool to improve eye care accessibility, especially in underdeveloped areas with limited eye care personnel and resources.

PURPOSE. We investigate the impact of parental myopia on spherical equivalent (SE) progression and axial length (AL) elongation. METHODS. Children and their parents were invited for annual examinations from 2006 (baseline). Cycloplegic autorefraction and AL were measured at each visit. Parental refractive status was determined using refraction data from their baseline visit. Children were classified into five groups: no myopic parents (non-non), only one moderately myopic parent (nonmoderate), only one highly myopic parent (non-high), two moderately myopic parents (moderate-moderate), and one moderately myopic or more severe and one highly myopic parent (moderate-high/high-high). The relationship between progression of SE and AL with parental refractive status was estimated by linear mixed-effects models. Data from 2006 to 2017 were analyzed in the current study. RESULTS. A total of 1831 children were enrolled (mean age, 11 6 2.7 years; mean standard error, À0.49 6 2.16 diopters [D] at baseline. Myopia progressed faster for children with parental myopia (non-non group as reference, all P < 0.05), while AL elongation mirrored the change in SE (all P < 0.001 except for non-mod group P ¼ 0.12). As for the age-specific change in SE and AL, children in the mod-high/high-high group presented with the fastest progression. Children with highly myopic parents were at higher risks of being highly myopic during adulthood (odds ratio ¼ 13.98 and 25.71 for non-high and mod-high/high-high groups; both P < 0.001). CONCLUSIONS. SE progresses and AL elongates at a faster rate at an earlier age in children with parental myopia. Children with highly-myopic parents have higher risks of being highly myopic during adulthood.

Importance Data on the incidence of presenting vision impairment (PVI) and spectacle coverage rate (SCR) in urban China is limited. Background To estimate the 6‐year incidence and risk factors for PVI and the SCR in urban Southern China. Design Population‐based cohort study. Participants A total of 1817 participants aged ≥35 years were identified from Guangzhou in 2008 at baseline and 1427 attended follow‐up examination in 2014. Methods Presenting visual acuity (PVA) was measured using the ETDRS chart with habitual spectacles. Participants with PVA ≤20/40 underwent subjective refraction at the follow‐up visit. Incidence of PVI was calculated using the WHO and US criteria, respectively. The met‐need SCR was defined as the percentage of participants with PVA <20/40 that had been improved to ≥20/40 after correction. Main Outcome Measures Incidence of PVI and SCR. Results Incidence of PVI was 8.3% (95%CI, 6.9‐9.8) and 12.2% (95%CI, 10.5‐14.0) based on the WHO and US definition, respectively. Older age, female, lower education level, more myopic spherical equivalent and worse PVA at baseline were significantly related to a higher PVI incidence based on the WHO criteria, with similar associations identified using the US criteria except for gender. The overall met‐need SCR was 42.5%, and was lower among the elderly, more hyperopic participants or participants with lower education level. Conclusions and Relevance The incidence of PVI is high in urban Southern China and spectacle wearing is available in less than half of those in need. This highlights the needs to promote spectacle coverage even in the urban population.

Importance: Understanding visual impairment (VI) under different definitions and potential risk factors in high myopic is important for future myopia control. Background: Limited studies exists investigating the VI among high myopic and with varying VI definitions. Design: Registry cohort Study Participants: 884 participants from ZOC-BHVI Study Methods: Subjects aged 7-70 years with high myopia were enrolled. Uncorrected and best-corrected visual acuity (UCVA & BCVA), cycloplegic refraction, axial length (AL), corneal curvatures, anterior chamber depth and lens thickness were measured. Axial length/Corneal radius of curvature ratio (AL/CR ratio) was calculated. Fundus lesions were graded into 5 categories. VI and blindness were defined based on the better-seeing eye according to the World Health Organization (WHO) criteria and United States (US) criteria.Multiple logistic regression analysis was used to assess risk factors for VI. Main outcome measures: Rates of VI and blindnessResults: A total of 884 participants were included, with mean (SD) age 18.5 (12.4) years and 46.4% male. Rate of UCVI/blindness were 72.6%/27.3% and 17.9%/82.1% based on WHO and US criteria. With respect to BCVA, 4.1%/ 5.9% of participants had BCVI using two definitions, while the rate for blindness was 0.2% and 0.6%. After adjusting confounders, multiple logistic regression showed that more severe fundus lesions, greater AL/CR ratio were at a higher risk of being VI, both in two definitions (p<0.005). Conclusions and Relevance:The rate of VI and blindness in highly myopic patients varies significantly using different definition. Severe fundus lesions and greater AL/CR ratios were associated with a higher risk of VI.

Myopia has become a major visual disorder among school-aged children in East Asia due to its rising prevalence over the past few decades and will continue to be a leading health issue with an annual incidence as high as 20%-30%. Although various interventions have been proposed for myopia control, consensus in treatment strategies has yet to be fully developed. Atropine and orthokeratology stand out for their effectiveness in myopia progression control, but children with rapid progression of myopia require treatment with higher concentrations of atropine that are associated with increased rates of side effects, or with orthokeratology that carries risk of significant complication. Therefore, improved risk assessment for myopia onset and progression in children is critical in clinical decision-making. Besides traditional prediction models based on genetic effects and environmental exposures within populations, individualized prediction using machine learning and data based on age-specific refraction is promising. Although emerging treatments for myopia are promising and some have been incorporated into clinical practice, identifying populations who require and benefit from intervention remains the most important initial step for clinical practice.

Visual span, which is the number of recognizable letters seen without moving the eyes, has been proven to impose a sensory limitation for alphabetic reading speed (

PURPOSE. Evidence has indicated that the size of the visual span (the number of identifiable letters without movement of the eyes) and reading speed can be boosted through perceptual learning in alphabetic scripts. In this study, we investigated whether benefits of perceptual learning could be extended to visual-span size and sentence reading (all characters are presented at the same time) for Chinese characters and explored changes in sensory factors contributing to changes in visual-span size following training. METHODS. We randomly assigned 26 normally sighted subjects to either a control group (n ¼ 13) or a training group (n ¼ 13). Pre-and posttests were administered to evaluate visual-span profiles (VSPs) and reading speed. Training consisted of trigram (sequences of three characters) character-recognition trials over 4 consecutive days. VSPs are plots of recognition accuracy as a function of character position. Visual-span size was quantified as the area under VSPs in bits of information transmitted. A decomposition analysis of VSPs was used to quantify the effects of sensory factors (crowding and mislocation). We compared the size and sensory factors of visual span and reading speed following training. RESULTS. Following training, the visual-span size significantly increased by 11.7 bits, and reading speed increased by 50.8%. The decomposition analysis showed a significant reduction for crowding (À13.1 bits) but a minor increase in the magnitude of mislocation errors (1.46 bits) following training. CONCLUSIONS. These results suggest that perceptual learning expands the visual-span size and further improves Chinese text sentence-reading speed, indicating that visual span may be a common sensory limitation on reading that can be overcome with practice.