The Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) Study-Defining a Threshold for Non-Cycloplegic Myopia Prevalence in Children

Ocular Biometry Percentile Curves and Their Relation to Myopia Development in Indian Children

Background: The aim of the present study was to provide ocular biometry percentile values for Indian children between the ages of 6 and 12 and to validate the usefulness of centiles in predicting myopia development. Methods: The study was part of a longitudinal study-the Sankara Nethralaya Tamil Nadu Essilor Myopia Study (STEM), where objective refraction and ocular biometry were measured for children studying in grades 1, 4, and 6 at baseline (2019-2020). These data were used to generate ocular biometry percentile curves (both for axial length (AL) and AL/corneal curvature (AL/CR) ratios). The usefulness of percentile values in predicting myopia development was estimated from follow-up data (2022). Results: The total number of children in the three grades at baseline was 4514 (age range 6 to 12). Boys represented 54% (n = 2442) of the overall sample. The prevalence of myopia at baseline was 11.7% (95% CI from 10.8 to 12.7%) in these three grades. Both the AL and AL/CR ratio centiles showed a linear trend with an increase in AL and AL/CR with increasing grades (p < 0.001) for all percentiles (2, 5, 10, 25, 50, 75, 90, 95, 98, and 99) when stratified by sex. In the follow-up data (n = 377), the 75th and 50th percentiles of the AL/CR ratio had an area under the curve (AUC) of 0.79 and 0.72 to predict myopia onset for grade 4 and 6 children at baseline. Combining baseline AL with the centile shift in follow-up as a predictor increased the AUC to 0.83. Conclusions: The present study has provided centile values specific for Indian children between the ages of 6 and 12 to monitor and intervene where children are at a higher risk of myopia development.

Priorities in school eye health in low and middle-income countries a scoping review

School eye health (SEH) has been on the global agenda for many years, and there is mounting evidence available to support that school-based visual screenings are one of the most effective and cost-efficient interventions to reach children over five years old. A scoping review was conducted in MEDLINE, Web of Science, PubMed, and CINHAL between February and June 2023 to identify current priorities in recent literature on school eye health in low- and middle-income countries (LMICs). Selection of relevant publications was performed with Covidence, and the main findings were classified according to the WHO Health Promoting Schools framework (HPS). A total of 95 articles were included: cross-sectional studies (n = 55), randomised controlled trials (n = 7), qualitative research (n = 7) and others. Results demonstrate that multi-level action is required to implement sustainable and integrated school eye health programmes in low and middle-income countries. The main priorities identified in this review are: standardised and rigorous protocols; cost-effective workforce; provision of suitable spectacles; compliance to spectacle wear; efficient health promotion interventions; parents and community engagement; integration of programmes in school health; inter-sectoral, government-owned programmes with long-term financing schemes. Even though many challenges remain, the continuous production of quality data such as the ones presented in this review will help governments and other stakeholders to build evidence-based, comprehensive, integrated, and context-adapted programmes and deliver quality eye care services to children all over the world.

Method comparison and overview of refractive measurements in children: implications for myopia management

OBJECTIVE

This study investigated the agreement between objective wavefront-based refraction and subjective refraction in myopic children. It also assessed the impact of cyclopentolate and refraction levels on the agreement.

METHODS

A total of 84 eyes of myopic children aged 6-13 years were included in the analysis. Non-cycloplegic and cycloplegic objective wavefront-based refraction were determined and cycloplegic subjective refraction was performed for each participant. The data were converted into spherical equivalent, J0 and J45, and Bland-Altman plots were used to analyse the agreement between methods.

RESULTS

Linear functions were used to determine the dependency between the central myopic refractive error and the difference between the method of refraction (=bias). The influence of central myopia was not clinically relevant when analysing the agreement between wavefront results with and without cyclopentolate (comparison 1). The bias for wavefront-based minus subjective spherical equivalent refraction (comparison 2) was ≤-0.50 D (95% limits of agreement -0.010 D to -1.00 D) for myopia of -4.55 D and higher when cycloplegia was used (p<0.05). When no cyclopentolate was used for the wavefront-based refraction (comparison 3), the bias of -0.50 D (95% limits of agreement -0.020 D to -0.97 D) was already reached at a myopic error of -2.97 D. Both astigmatic components showed no clinically relevant bias.

CONCLUSION

The spherical equivalent, measured without cycloplegic agents, led to more myopic measurements when wavefront-based refraction was used. The observed bias increased with the amount of myopic refractive error for comparisons 2 and 3, which needs to be considered when interpreting wavefront-refraction data.

TRIAL REGISTRATION NUMBER

NCT05288335.

The Definition-Dependent Nature of Myopia Prevalence: A Nationwide Study of 1.5 Million Adolescents

PURPOSE

The application of myopia definition varies considerably within the literature. The purpose of this study was to examine the relationship between different myopia and high myopia definitions and resultant prevalence estimates.

METHODS

A population-based cross-sectional study of 1,588,508 Israeli adolescents assessed for medical fitness before mandatory military service at the age of 17 years between 1993 through 2015. Participants underwent non-cycloplegic autorefraction. Nine definitions of myopia and seven definitions of high myopia were examined. Prevalence estimates for each definition were calculated and compared with the reference definition (right eye spherical equivalent (SE)≤-0.50D and ≤-6.00D for myopia and high myopia, respectively), to yield a rate ratio (RR) across definitions.

RESULTS

Applying the right eye SE≤-0.50D reference definition yielded 31.0% myopia prevalence. While some definitions resulted in similar prevalence estimates, using the right eye SE of ≤-0.75D; ≤-1.00D or least minus meridian of ≤-0.75D definitions yielded 28.8%, 26.3%, and 26.9% myopia prevalence, respectively, which corresponded to a 7.1%, 15.1% and 13.4% reduction in myopia RR, respectively. The prevalence of high myopia demonstrated considerable alternations, with a 1.7-fold increase in prevalence for the narrower threshold of SE≤-5.00D compared with SE≤-6.00D reference definition (4.2% and 2.4%, respectively).

CONCLUSIONS

The prevalence of myopia and especially high myopia varies between frequently applied definitions, considering diverse thresholds, eye lateralization, and spherical vs. astigmatic refractive components. This variability highlights the pressing need for standardization of myopia definition in ophthalmic research. The results of this study provide crude estimates of a "conversion rate" across data, allowing comparisons between studies that utilize different myopia definitions.

Analysis of 2-year spherical equivalent progression in emmetropic children with non-cycloplegic refraction: a retrospective chart review

BACKGROUND

We aimed to investigate children with an emmetropic non-cycloplegic refraction (NCR) to compare the difference in progression of NC spherical equivalent (SE) over 2 years between the children with emmetropic and hyperopic cycloplegic refraction (CR) values.

METHODS

Through a retrospective medical record review, 59 children aged under 10 years were evaluated. Refractive error was calculated as the average of the SE values of both eyes. According to the CR results, children with emmetropia (-0.50 to 1.00 diopter [D]) were assigned to group 1 (n = 29), and those with hyperopia (≥ 1.00 D) were assigned to group 2 (n = 30). The prevalence of myopia and SE progression were compared over 2 years. Correlations between final SE progression and baseline age and refractive error were analyzed and multiple regression analysis was conducted. Receiver operating characteristic curves that achieved the best cutoff points to distinguish between the groups were calculated.

RESULTS

Group 1 showed significantly myopic SE changes compared to baseline at the 1-year follow-up, and group 1 was significantly myopic compared with group 2 at the 2-year follow-up. Myopia prevalence was 51.7% in group 1 and 6.7% in group 2 after 1 year, and 61.1% and 16.7% after 2 years, respectively. In the correlation analysis, baseline age, baseline CR, and difference between CR and NCR showed significant correlations with the 2-year SE progression (r = -0.359, p = 0.005; r = 0.450, p < 0.001; r = -0.562, p < 0.001, respectively). However, NCR refractive error showed no significant correlation (r = -0.097, p = 0.468). In multiple regression analysis, baseline age (β= -0.082), and CR-NCR difference (β= -0.214) showed a significant effect on SE progression for 2 years. When an NCR value of 0.20 D was set as the cut-off value to distinguish between the groups, a sensitivity of 70% and specificity of 92% were obtained.

CONCLUSION

Even if NCR showed emmetropia, children with baseline CR values of emmetropia showed greater SE progression compared with those with hyperopia. Cycloplegia is essential to confirm the correct refractive status in children. It may be useful for predicting prognosis of SE progression.

Myopia and Its Association with Near Work, Outdoor Time, and Housing Type among Schoolchildren in South India

SIGNIFICANCE

In this comprehensive assessment of environmental associations with refractive status among schoolchildren in India, outdoor time was the key modifiable risk factor associated with myopia rather than time spent on near work.

PURPOSE

This study aimed to investigate the environmental risk factors associated with myopia among adolescent schoolchildren in South India.

METHODS

Children in grades 8 to 10 from 11 schools in Tamil Nadu, South India, underwent eye examination and risk factor assessments through a modified version of the Sydney myopia questionnaire. Time spent on near work and outdoors was analyzed after division into three groups based on tertiles. Mixed-effects logistic regression was performed to assess the factors associated with myopia.

RESULTS

A total of 3429 children (response rate, 78.4%) provided both questionnaire and refraction data. The mean (standard deviation) age was 14 (0.93) years with an equal distribution of sexes. Myopia was present among 867 children (noncycloplegic spherical equivalent refraction, ≤-0.75 D). Refraction was not associated with near work tertiles ( P = .22), whereas less time outdoors was associated with higher myopic refractions ( P = .01). Refraction shifted toward increased myopia with an increase in the near-work/outdoor time ratio ( P = .005). Children living in apartment housing had a higher prevalence of myopia compared with other types of housing ( P < .001). In multivariate analysis, increased time outdoors was a protective factor against myopia (odds ratio, 0.79; 95% confidence interval, 0.63 to 0.99; P = .04), whereas living in apartment housing (odds ratio, 1.27; 95% confidence interval, 1.04 to 1.55; P = .02) was a significant risk factor.

CONCLUSIONS

In this cohort of Indian children, outdoor time, increased near-work/outdoor time ratio, and type of housing were the factors associated with myopia. Policies should target implementing a balance between near-work and outdoor time among children.

Clinical evaluation of autorefraction and subjective refraction with and without cycloplegia in Chinese school-aged children: a cross-sectional study

BACKGROUND

The accuracy of open-field autorefractors is important for vision screening, clinical care, and vision research, especially in patients with childhood myopia. TOPCON KR3000 autorefractor was conventional autorefractor and subjective refraction after cycloplegia was gold criteria for assessing the refraction. Results of refractive error in Chinese school-aged children obtained by three methods were evaluated and compared.

METHODS

A cross-sectional study was conducted. A total of 89 patients (with a total of 177 eyes) diagnosed as refractive error in the Affiliated Hospital of Nanjing University of Chinese Medicine from July 2020 to September 2020 were sequentially enrolled in this study. All subjects underwent routine ophthalmic examination to exclude other ocular diseases and had a best corrected visual acuity no less than 0.1 The spherical diopter (SD), spherical equivalence (SE), and astigmatism (J0 and J45) were determined in patients before cycloplegia using two autorefractors, and again after cycloplegia. Subjective refraction results were obtained simultaneously after cycloplegia as gold criteria for comparison. A comparison of data between three methods was performed using paired t-tests and presented graphically using Bland-Altman plots.

RESULTS

Before cycloplegia, the SD and SE results from WAM were 0.14 D and 0.12 D more positive than the reading from TOPCON (P=0.011 and P=0.021, respectively). The SD measured by WAM and TOPCON was 0.31 D and 0.45 D more negative than the values obtained by subjective refraction after cycloplegia, respectively (P<0.001 and P<0.001, respectively). The SE readings also showed a similar trend (P<0.001, P<0.001). After cycloplegia, the SD and SE measurement obtained with WAM were 0.13 D and 0.12 D more positive than those measured by TOPCON (P<0.001 and P<0.001, respectively), and this was not significantly different to the results obtained using subjective refraction. However, the results of SD, SE, and J0 measured by the TOPCON were significantly different from the results obtained using subjective refraction (P<0.001, P<0.001, and P=0.002, respectively).

CONCLUSIONS

In clinical application, the measurements obtained with the WAM-5500 autorefractor were more reliable than those of the TOPCON KR3000 autorefractor in patients with or without cycloplegia. The WAM-5500 Autorefractor represents a reliable and valid objective refraction tool for optometric practice.

Prevalence of myopia among urban and suburban school children in Tamil Nadu, South India: findings from the Sankara Nethralaya Tamil Nadu Essilor Myopia (STEM) Study

PURPOSE

To report the baseline prevalence of myopia among school children in Tamil Nadu, South India from a prospective cohort study.

METHODS

Children between the ages of 5 and 16 years from 11 schools in two districts of Tamil Nadu underwent vision screening. All children underwent visual acuity assessment using a Pocket Vision Screener followed by non-cycloplegic open-field autorefraction (Grand Seiko WAM-5500). Myopia was defined as a spherical equivalent (SE) refraction of ≤-0.75 D and high myopia was defined as SE ≤ -6.00 D. Distribution of refraction, biometry and factors associated with prevalence of myopia were the outcome measures.

RESULTS

A total of 14,699 children completed vision screening, with 2% (357) of them having ocular abnormalities other than refractive errors or poor vision despite spectacle correction. The remaining 14,342 children (7557 boys; 52.69%) had a mean age of 10.2 (Standard Deviation [SD] 2.8) years. A total of 2502 had myopia in at least one eye, a prevalence of 17.5% (95% CI: 14.7-20.5%), and 74 (0.5%; 95% CI: 0.3-0.9%) had high myopia. Myopia prevalence increased with age (p < 0.001), but sex was not associated with myopia prevalence (p = 0.24). Mean axial length (AL; 23.08 (SD = 0.91) mm) and mean anterior chamber depth (ACD; 3.45 (SD = 0.27) mm) positively correlated with age (p < 0.001). The mean flat (K1; 43.37 (SD = 1.49) D) and steep (K2; 44.50 (SD = 1.58) D) corneal curvatures showed negative correlation with age (p = 0.02 and p < 0.001, respectively). In the multivariable logistic regression, older age and urban school location had higher odds for prevalence of myopia.

CONCLUSION

The baseline prevalence of myopia among 5- to 16-year-old children in South India is larger than that found in previous studies, indicating that myopia is becoming a major public health problem in this country.

Development of Refractive Parameters in 3- to 6-Year-Old Children and Its Application in Myopia Prediction and Intervention Guidance

OBJECTIVE

To investigate refractive development and prevalence of myopia in children aged 3-6 years in Hebei Province, China, and to explore the developmental law of refraction, so as to clinically guide the prediction and intervention of myopia.

METHODS

In May 2019, a total of 6120 people were inspected in 68 kindergartens in 11 cities in Hebei Province. Child refractive refraction was checked under noncycloplegia using a handheld binocular vision screener (SW-800, SUOER, Tianjin, China). Axial length (AL) and corneal radius of curvature (CR) were measured using an ocular biometry (IOLMaster 500, Carl Zeiss, Germany). Myopia was defined as spherical equivalent (SE) ≤ -0.75 D.

RESULTS

A total of 5506 children aged 3-6 years met the criteria and were included in the statistical analysis. The prevalence of myopia was 3.49% (1.93% at age 3, 2.90% at age 4, 3.78% at age 5, and 3.88% at age 6). Overall, the mean SE was +0.67 ± 1.05 D (+0.81 ± 1.00 D at age 3, +0.79 ± 1.05 D at age 4, +0.67 ± 1.08 D at age 5, and +0.13 ± 1.01 D at age 6); the mean CR was 7.76 ± 0.26 mm (7.78 ± 0.26 mm at age3, 7.75 ± 0.25 mm at age 4, 7.77 ± 0.26 mm at age 5, and 7.76 ± 0.25 mm at age 6); the mean AL was 22.31 ± 0.73 mm (21.98 ± 0.63 mm at age 3, 22.12 ± 0.69 mm at age 4, 22.34 ± 0.73 mm at age 5, and 22.49 ± 0.73 mm at age 6).

CONCLUSIONS

Prevalence of myopia increases with age in children aged 3-6 years in Hebei, China. With the increase of age, CR is basically stable, and AL increases gradually. AL/CR, which is closely related to SE, can be used as an indicator to predict myopia and guide clinical work.

Design, methodology, and baseline of whole city-million scale children and adolescents myopia survey (CAMS) in Wenzhou, China

Background

Myopia is the most common visual impairment in children and adolescents worldwide. This study described an economical and effective population-based screening pipeline and performed the project of a million scale children and adolescents myopia survey (CAMS), which will shed light on the further study of myopia from the level of epidemiology and precision medicine.

Methods

We developed a novel population-based screening pattern, an intelligent screening process and internet-based information transmission and analysis system to carry out the survey consisting of school children in Wenzhou, China. The examination items include unaided distance visual acuity, presenting distance visual acuity, and non-cycloplegic autorefraction. Myopia and high myopia were defined as spherical equivalent (SE) ≤ − 1.00 diopters (D) and SE ≤ − 6.00 D, respectively. Next, the reports of the vision checking were automatically sent to parents and the related departments. The CAMS project will be done two to four times annually with the support of the government. An online eyesight status information management system (OESIMS) was developed to construct comprehensive and efficient electronic vision health records (EVHRs) for myopia information inquiry, risk pre-warning, and further study.

Results

The CAMS completed the first-round of screening within 30 days for 99.41% of Wenzhou students from districts and counties, in June 2019. A total of 1,060,925 participants were eligible for CAMS and 1,054,251 (99.37% participation rate) were selected through data quality control, which comprised 1305 schools, and 580,609, 251,050 and 170,967 elementary, middle, and high school students. The mean age of participants was 12.21 ± 3.32 years (6–20 years), the female-to-male ratio was 0.82. The prevalence of myopia in elementary, middle, and high school students was 38.16%, 77.52%, and 84.00%, respectively, and the high myopia incidence was 0.95%, 6.90%, and 12.98%.

Conclusions

The CAMS standardized myopia screening model involves automating large-scale information collection, data transmission, data analysis and early warning, thereby supporting myopia prevention and control. The entire survey reduced 90% of staff, cost, and time consumption compared with previous surveys. This will provide new insights for decision support for public health intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-021-00255-1.