Myopia screening: combining visual acuity and noncycloplegic autorefraction

Sympathetic nervous system activity is associated with choroidal thickness and axial length in school-aged children

BACKGROUND/AIMS

We aim to explore the effect of sympathetic nervous system (SNS) on choroid thickness (ChT) and axial length (AL).

METHODS

Students of grade 2 and 3 from a primary school were included and followed for 1 year. Visual acuity, refraction, AL and ChT were measured. Morning urine samples were collected for determining SNS activity by analysing concentrations of epinephrine, norepinephrine and dopamine using the liquid chromatography-tandem mass spectrometry. The most important factor (factor 1) was calculated using factor analysis to comprehensively indicate the SNS activity.

RESULTS

A total of 273 students were included, with an average age of 7.77±0.69 years, and 150 (54.95%) were boys. Every 1 µg/L increase in epinephrine is associated with 1.60 µm (95% CI 0.30 to 2.90, p=0.02) decrease in average ChT. Every 1 µg/L increase in norepinephrine is associated with 0.53 µm (95% CI 0.08 to 0.98, p=0.02) decrease in the ChT in inner-superior region. The factor 1 was negatively correlated with the ChT in the superior regions. Every 1 µg/L increase in norepinephrine was associated with 0.002 mm (95% CI 0.0004 to 0.004, p=0.016) quicker AL elongation. The factor 1 was positively correlated with AL elongation (coefficient=0.037, 95% CI 0.005 to 0.070, p=0.023).

CONCLUSIONS

We hypothesised that chronic stress characterised by elevated level of the SNS, was associated with significant increase in AL elongation, probably through thinning of the choroid.

Cutoff values of axial length/corneal radius ratio for determining myopia vary with age among 3-18 years old children and adolescents

PURPOSE

To investigate the effectiveness and cutoffs of axial length/corneal radius (AL/CR) ratio for myopia detection in children by age.

METHODS

Totally, 21 kindergartens and schools were enrolled. Non-cycloplegic autorefraction (NCAR), axial length (AL), horizontal and vertical meridian of corneal radius (CR1, CR2), and cycloplegic autorefraction were measured. Receiver operating characteristic (ROC) curve was used to obtain the effectiveness and cutoff for myopia detection.

RESULTS

Finally, 7803 participants aged 3-18 years with mean AL/CR ratio of 2.99 ± 0.16 were included. Area under the ROC curve (AUC) of AL/CR ratio for myopia detection (0.958 for AL/CR1, 0.956 for AL/CR2, 0.961 for AL/CR) was significantly larger than that of AL (0.919, all P < 0.001), while AUCs of the three were similar with different cutoffs (> 2.98, > 3.05, and > 3.02). When divided by age, the ROC curves of AL/CR ratio in 3- to 5-year-olds showed no significance or low accuracy (AUCs ≤ 0.823) in both genders. In ≥ 6-year-olds, the accuracies were promising (AUCs ≥ 0.883, all P < 0.001), the cutoffs basically increased with age (from > 2.93 in 6-year-olds to > 3.07 in 18-year-olds among girls, and from > 2.96 in 6-year-olds to > 3.07 in 18-year-olds among boys). In addition, boys presented slightly larger cutoffs than girls in all ages except for 16 and 18 years old. For children aged 3-5 years, AL/CR ratio or AL combined with NCAR increased AUC to > 0.900.

CONCLUSION

AL/CR ratio provided the best prediction of myopia with age-dependent cutoff values for all but preschool children, and the cutoffs of boys were slightly larger than those of girls. For preschool children, AL/CR ratio or AL combined with NCAR is recommended to achieve satisfactory accuracy. AL/CR ratio calculated by two meridians showed similar predictive power but with different cutoffs.

Green Space Morphology and School Myopia in China

Importance

China has experienced both rapid urbanization and major increases in myopia prevalence. Previous studies suggest that green space exposure reduces the risk of myopia, but the association between myopia risk and specific geometry and distribution characteristics of green space has yet to be explored. These must be understood to craft effective interventions to reduce myopia.

Objective

To evaluate the associations between myopia and specific green space morphology using novel quantitative data from high-resolution satellite imaging.

Design, Setting, and Participants

This prospective cohort study included students grades 1 to 4 (aged 6 to 9 years) in Shenzhen, China. Baseline data were collected in 2016-2017, and students were followed up in 2018-2019. Data were analyzed from September 2020 to January 2022.

Exposures

Eight landscape metrics were calculated using land cover data from high-resolution Gaofen-2 satellite images to measure area, aggregation, and shape of green space.

Main Outcome and Measures

The 2-year cumulative change in myopia prevalence at each school and incidence of myopia at the student level after 2 years were calculated as main outcomes. The associations between landscape metrics and school myopia were assessed, controlling for geographical, demographic, and socioeconomic factors. Principal component analyses were performed to further assess the joint effect of landscape metrics at the school and individual level.

Results

A total of 138 735 students were assessed at baseline. Higher proportion, aggregation, and better connectivity of green space were correlated with slower increases in myopia prevalence. In the principal component regression, a 1-unit increase in the myopia-related green space morphology index (the first principal component) was negatively associated with a 1.7% (95% CI, -2.7 to -0.6) decrease in myopia prevalence change at the school level (P = .002). At the individual level, a 1-unit increase in myopia-related green space morphology index was associated with a 9.8% (95% CI, 4.1 to 15.1) reduction in the risk of incident myopia (P < .001), and the association remained after further adjustment for outdoor time, screen time, reading time, and parental myopia (adjusted odds ratio, 0.88; 95% CI, 0.80 to 0.97; P = .009).

Conclusions and Relevance

Structure of green space was associated with a decreased relative risk of myopia, which may provide guidance for construction and renovation of schools. Since risk estimates only indicate correlations rather than causation, further interventional studies are needed to assess the effect on school myopia of urban planning and environmental designs, especially size and aggregation metrics of green space, on school myopia.

Worsening vision at age 4-5 in England post-COVID: Evidence from a large database of vision screening data

PURPOSE

Myopia prevalence has increased in the UK at age 10-16y, but little is known about younger children. We hypothesise that if the 'myopia epidemic' is affecting young children, then there will be increasing rates of bilateral reduced unaided vision (V) at vision screenings of children 4-5 years of age.

METHODS

Retrospective anonymised data from computerised vision screening at age 4-5 years were analysed from serial cross-sectional data. Refractive error is not assessed in UK vision screening, so vision was investigated. Data were only included from schools that screened every year from 2015/16 to 2021/22. The criterion used was unaided monocular logMAR (automated letter-by-letter scoring) vision >0.20 in both the right and left eyes, so as to maximise the chances of detecting bilateral, moderate myopia rather than amblyopia.

RESULTS

Anonymised raw data were obtained for 359,634 screening episodes from 2075 schools. Once schools were excluded where data were not available for every year and data were cleaned, the final database comprised 110,076 episodes. The proportion (percentage and 95% CI) failing the criterion from 2015/16 to 2021/22 were 7.6 (7.2-8.0), 8.5 (8.1-8.9), 7.5 (7.1-7.9), 7.8 (7.4-8.2), 8.7 (8.1-9.2), 8.5 (7.9-9.0) and 9.3 (8.8-9.7), respectively. The slope of the regression line showed a trend for increasing rates of reduced bilateral unaided vision, consistent with increasing frequency of myopia (p = 0.06). A decreasing linear trendline was noted for children 'Under Professional Care'.

CONCLUSIONS

For children 4-5 years of age, there were signs of reduced vision over the last 7 years in England. Consideration of the most likely causes support the hypothesis of increasing myopia. The increase in screening failures highlights the importance of eye care in this young population.

Prevalence of myopia and uncorrected myopia among 721 032 schoolchildren in a city-wide vision screening in southern China: the Shantou Myopia Study

AIMS

To explore the prevalence and risk factors for myopia and uncorrected myopia in schoolchildren in southern China.

METHODS

The government-led Shantou Myopia Study was conducted from September 2020 to June 2021. Non-cycloplegic refraction was performed. Uncorrected visual acuity (UCVA) was measured along with presenting visual acuity if participants wore spectacles. Spherical equivalent refraction (SER) is defined as the spherical dioptres added to half of the cylindrical dioptres. Myopia is defined as SER <-0.50 dioptre with UCVA of <20/20 in at least one eye.

RESULTS

This study enrolled 724 828 schoolchildren (77.8% of all schoolchildren in Shantou) from 901 schools. Data from 721 032 schoolchildren (99.5%) were analysed (mean age 11.53±3.13 years, 6-20 years, 373 230 boys and 347 802 girls). Among them, 373 459 (51.8%) had myopia: 37.1% of 465 696 children in primary schools, 75.4% of 170 164 children in junior high schools and 84.8% of 85 172 children in senior high schools. The prevalence of myopia increases non-linearly with age. Older age, female and urban living environment were independently associated with myopia prevalence and myopic SER. Among the 373 459 children with myopia, 60.0% had no refractive correction: 74.9%, 53.9% and 35.5% in primary, junior high and senior high schools, respectively.

CONCLUSION

The overall prevalence of myopia among schoolchildren in Shantou was 51.8%, higher than the national average in China. The proportion of uncorrected myopia is high, especially in primary schools. Our results indicate the need for public education on eye care among schoolchildren even in a municipal city.

How to Conduct School Myopia Screening: Comparison Among Myopia Screening Tests and Determination of Associated Cutoffs

PURPOSE

To compare the accuracy for various screening tests and their combined uses for myopia screening among children and adolescents and explore age-specific cutoffs.

DESIGN

Cross-sectional study.

METHODS

A total of 6017 children and adolescents aged 4 to 15 years participated in the study. Uncorrected visual acuity (UCVA, recorded in decimal notation), cycloplegic and noncycloplegic refraction (NCR), axial length (AL), and corneal curvature radius (CR) examinations were performed. Cycloplegic spherical equivalent ≤-0.50 D was considered as the gold standard for myopia. Receiver operating characteristic (ROC) curves were drawn to determine optimal cutoffs for all age groups, and sensitivity, specificity, as well as screening prevalence of myopia were calculated.

RESULTS

The overall estimate of myopia prevalence was 31.8% using the gold standard. The sensitivity and specificity of the UCVA alone for the commonly used cutoff (1.0) were 97.7% and 33.1%, respectively. The areas under the ROC curve were optimally estimated to be 0.985 (95% CI, 0.982-0.988) for the combined use of UCVA and NCR tests, and 0.987 (95% CI, 0.983-0.989) for the combined use of AL/CR and NCR tests, with no significant difference (P = 0.208). The best cutoffs for UCVA-NCR combinations were UCVA <1.0 and NCR <-0.25 D in 4 to 6 years; UCVA <1.0 and NCR <-0.50 D in 7 to 12 years; UCVA <0.8 and NCR <-0.75 D in 13 to 15 years. If those screening positive were all referred to clinics and corrected with cycloplegic autorefraction data, the relative difference between screening prevalence and the actual prevalence by the gold standard would reduce from 13.2% to 4.7%.

CONCLUSIONS

UCVA test alone for detecting myopia demonstrated a poorer accuracy among these tests. The combined use of UCVA and NCR tests and the combined use of AL/CR and NCR tests achieved optimal accuracy for myopia screening. Setting age-specific cutoffs would increase the accuracy, and the prevalence obtained from primary screening should be corrected according to the data of cycloplegic refraction after referral, especially in younger ages.

Difference of refractive status before and after cycloplegic refraction: the Lhasa Childhood Eye Study

PURPOSE

To compare the differences between cycloplegic and noncycloplegic refraction as well as associated factors in grade one students of primary schools, and explore the effectiveness of noncycloplegic refraction for refractive error screening.

STUDY DESIGN

Cross-sectional study.

METHODS

A school-based study of 1856 students was conducted in Lhasa, Tibetan Plateau, China. Cycloplegia was achieved with two drops of 1% cyclopentolate and 1 drop of Mydrin P at a 5-min interval. Autorefraction was performed under both cycloplegic and noncycloplegic conditions. Bland-Altman analysis, receiver operating characteristic curve analysis, univariate and multiple linear regression models were used for analysis.

RESULTS

Of the 1856 children enrolled, 1830 (98.60%) completed all procedures. The average age was 6.83 ± 0.46 years. 965 (52.73%) children were boys and 1737 (94.92%) were Tibetan. Overall, there was a significant difference between cycloplegic and noncycloplegic SE of 0.90 ± 0.76D (P < 0.001). However, the intra-class coefficient correlation (ICC) for cylinder between these two methods was high (ICC = 0.941, 95% CI, 0.935-0.946). Larger differences between cycloplegic and noncycloplegic SE were associated with hyperopic RE and higher cylindrical value (P < 0.001). The prevalence of myopia, emmetropia and hyperopia with and without cycloplegia was (3.93% vs 14.59%), (9.95% vs 45.8%) and (86.21% vs 39.56%), respectively. Myopia, emmetropia and hyperopia based on noncycloplegic refraction was defined as SE ≤ - 0.625D, - 0.625 < SE ≤ 0D, and SE > 0D, respectively.

CONCLUSIONS

Lack of cycloplegia leads to underestimation of hyperopia, with overestimation of myopia and emmetropia. Larger hyperopic refraction exhibited greater difference between cycloplegic and noncycloplegic refraction.

Proportion and characteristic of emmetropia in schoolchildren aged 6-11y: the Shenzhen elementary school eye study

AIM

To investigate the proportion and characteristic of emmetropia in schoolchildren aged 6-11, especially estimate the normal value of ocular biometric parameters of emmetropia.

METHODS

A population-based cross-sectional study was conducted on children aged 6-11y in Shenzhen. Totally, 2386 schoolchildren from two primary schools were involved. The axial length (AL) and the corneal radius of curvature (CRC) were measured by partial coherence laser interferometry. Noncycloplegic refraction and refractive astigmatism (RA) was measured using autorefraction. The axial length-to-corneal radius of curvature ratio (AL/CRC), corneal astigmatism (CA) and spherical equivalent refraction (SER) were calculated.

RESULTS

The proportion of emmetropia in elementary school students was 41.30%. This percentage decreased gradually from 6 to 11 years of age and decreased rapidly after 9 years of age. The mean and 95%CI of each parameter were provided for boys and girls aged 6 to 11 years of age with emmetropia according to each age group. The change trend of parameters of boys and girls are similar. After 7 years of age, the AL of non-emmetropia started to increase faster than that of emmetropia. The change trend of AL/CRC was the same as that of AL. The other parameters tend to be stable after 7 years of age.

CONCLUSION

The age of 7-9 is an important period for the changes of refractive state and ocular biometric parameters of primary school students, and it is a special focus period for children myopia prevention. The normal value and variation of ocular biometric parameters of emmetropia can provide the basis for the clinical judgment of whether or not children's ocular biometric parameters obtained by single measurement and changes obtained by multiple measurements are abnormal.

Myopia

Myopia, also known as short-sightedness or near-sightedness, is a very common condition that typically starts in childhood. Severe forms of myopia (pathologic myopia) are associated with a risk of other associated ophthalmic problems. This disorder affects all populations and is reaching epidemic proportions in East Asia, although there are differences in prevalence between countries. Myopia is caused by both environmental and genetic risk factors. A range of myopia management and control strategies are available that can treat this condition, but it is clear that understanding the factors involved in delaying myopia onset and slowing its progression will be key to reducing the rapid rise in its global prevalence. To achieve this goal, improved data collection using wearable technology, in combination with collection and assessment of data on demographic, genetic and environmental risk factors and with artificial intelligence are needed. Improved public health strategies focusing on early detection or prevention combined with additional effective therapeutic interventions to limit myopia progression are also needed.

Automatic identification of myopia based on ocular appearance images using deep learning

Background

Myopia is the leading cause of visual impairment and affects millions of children worldwide. Timely and annual manual optometric screenings of the entire at-risk population improve outcomes, but screening is challenging due to the lack of availability and training of assessors and the economic burden imposed by the screenings. Recently, deep learning and computer vision have shown powerful potential for disease screening. However, these techniques have not been applied to large-scale myopia screening using ocular appearance images.

Methods

We trained a deep learning system (DLS) for myopia detection using 2,350 ocular appearance images (processed by 7,050 pictures) from children aged 6 to 18. Myopia is defined as a spherical equivalent refraction (SER) [the algebraic sum in diopters (D), sphere + 1/2 cylinder] ≤−0.5 diopters. Saliency maps and gradient class activation maps (grad-CAM) were used to highlight the regions recognized by VGG-Face. In a prospective clinical trial, 100 ocular appearance images were used to assess the performance of the DLS.

Results

The area under the curve (AUC), sensitivity, and specificity of the DLS were 0.9270 (95% CI, 0.8580–0.9610), 81.13% (95% CI, 76.86–5.39%), and 86.42% (95% CI, 82.30–90.54%), respectively. Based on the saliency maps and grad-CAMs, the DLS mainly focused on eyes, especially the temporal sclera, rather than the background or other parts of the face. In the prospective clinical trial, the DLS achieved better diagnostic performance than the ophthalmologists in terms of sensitivity [DLS: 84.00% (95% CI, 73.50–94.50%) versus ophthalmologists: 64.00% (95% CI, 48.00–72.00%)] and specificity [DLS: 74.00% (95% CI, 61.40–86.60%) versus ophthalmologists: 53.33% (95% CI, 30.00–66.00%)]. We also computed AUC subgroups stratified by sex and age. DLS achieved comparable AUCs for children of different sexes and ages.

Conclusions

This study for the first time applied deep learning to myopia screening using ocular images and achieved high screening accuracy, enabling the remote monitoring of the refractive status in children with myopia. The application of our DLS will directly benefit public health and relieve the substantial burden imposed by myopia-associated visual impairment or blindness.

Refractive Error in Chinese Preschool Children: The Shanghai Study

Purpose:

To examine the prevalence of refractive error and some associated factors in Chinese preschool children.

Methods:

The Jinshan District Eye Study was a school-based survey of eye health in a large sample of 4- to 6-year-olds attending kindergartens from May 2013 to December 2013 in Shanghai. Refractive error was measured using an autorefractor under noncycloplegic conditions. Axial length (AL) was measured with an ocular biometry system. In addition, body height and weight were also recorded.

Results:

A total of 7,166 children successfully completed their refraction measurements. The median (interquartile range) of spherical equivalent (SE) for all the children was +0.25 D (−0.13 D to +0.62 D), and the range was −15.88 to +18.13 D. The mean AL for all the children was 22.35±0.70 mm, and the range was 18.20 to 27.71 mm. The overall prevalence of myopia (−1.00 D or less), hyperopia (+2.00 D or greater), and astigmatism (1.00 D or greater) were 5.9%, 1.0%, and 12.7%, respectively. After multivariate analysis, more myopic SE (or less hyperopic SE) was significantly associated with girls, longer AL, taller, and lighter.

Conclusion:

Shanghai has a high prevalence of refractive error in the world. However, longitudinal studies are needed to evaluate refractive changes over time in individual children and warranted to prevent the development of myopia.

Using Decision Curve Analysis to Evaluate Common Strategies for Myopia Screening in School-Aged Children

Purpose: To evaluate common strategies for screening myopia. Methods: A total of 2,248 children aged 6 to 12 years from five randomly selected primary schools were included for the screening. Enrolled study participants underwent distant uncorrected visual acuity (UCVA, Standard Logarithmic Visual Acuity E Chart) and non-cycloplegic auto-refraction (NCAR, Topcon KR-8800). Among them, 1,639 children (72.9%) accepted cycloplegic auto-refraction. Taking rejection of cycloplegia into account, receiver operating characteristic curves were drawn to compare the accuracies of the four strategies (I, Cycloplegic auto-refraction; II, NCAR; III, UCVA; IV, Combination of UCVA and NCAR). Decision curve analysis (DCA) was used to compare net benefits. Tenfold cross-validation was used for statistical analyses. Results: For myopia (spherical equivalent refraction, SE ≤ -0.5D) screening, the mean sensitivities were 73.79% (SD: 5.40%), 85.57% (6.84%), 59.71% (13.49%), and 85.06% (6.68%) for Strategy I to IV; with mean specificities of 100% (0%), 87.43% (4.27%), 89.74% (10.25%), and 88.65% (5.07%), respectively. For screening early myopia (SE ≤ -0.5D and ≥-1.0D), the mean sensitivities were 73.44% (7.69%), 82.39% (5.32%), 54.27% (14.58%), and 81.76% (9.60%) for Strategy I to IV; with mean specificities of 100% (0%), 79.13% (4.86%), 85.48% (9.86%), and 81.17% (4.16%). Based on DCA, the net benefits of Strategy IV were the highest, with the probability thresholds ranging from 12% to 50%, after adjusting the TestHarms. For early myopia, the net benefits of Strategy IV were the highest with the probability threshold ranging from 5% to 34%. Conclusion: Combination of UCVA and NCAR produced the highest net benefits for myopia screening.

Myopia Growth Chart Based on a Population-Based Survey (KNHANES IV-V): A Novel Prediction Model of Myopic Progression in Childhood

PURPOSE

To introduce a novel myopia growth chart based on a population-based survey for the prediction of myopic progression.

METHODS

The study included 7,695 Korean participants aged 5 to 20 years from a population-based health survey (Korean National Health and Nutrition Examination Survey IV-V). The authors collected spherical equivalent (SE) data converted from noncycloplegic refraction data. To create a myopia growth chart, data were arranged in the order of SE from hyperopia to myopia to acquire specific percentiles of the SE by age. Myopia progression rates were calculated between two specific ages in each percentile.

RESULTS

The mean age of the participants was 11.8 years and the mean SE was -1.82 diopters (D). The SE of the 10th percentile was +0.72 D for participants aged 5 and -0.25 D for those aged 20 years, resulting in a total change in refraction of -0.97 D. In contrast, the SE of the 90th percentile was -0.75 D for participants aged 5 years and -6.73 D for those aged 20 years, showing myopia progression of -5.98 D. The myopia progression rate from 5 to 20 years of age was estimated as -0.06, -0.15, and -0.40 D/year in the 10th, 50th, and 90th percentile groups, respectively.

CONCLUSIONS

The myopia growth chart may be used to diagnose the severity or to estimate the progression of myopia. A patient in a higher percentile of myopia for his or her age may have myopia progressing at a faster rate and thus require close observation. [J Pediatr Ophthalmol Strabismus. 2019;56(2):73-77.].

Effect of cycloplegia on the measurement of refractive error in Chinese children

Background

To compare the results of cycloplegic and non‐cycloplegic refractive error measurement in Chinese children, and to assess the relationship between age and the difference in refractive error measured with and without cycloplegia.

Methods

This was a prospective study that recruited 224 healthy Chinese children at an ophthalmology clinic from November 2016 to February 2017. Refraction before and after cycloplegia were measured using an auto‐refractor. Then spherical equivalent M, J₀, and J₄₅ were calculated. The enrolled children were allocated into three groups according to M: myopia, emmetropia, and hyperopia. The distribution of the refraction was further analysed by stratifying by age: four to six years, seven to 11 years, and 12 to 16 years.

Results

Mean non‐cycloplegic M, J₀, and J₄₅ were −1.68 ± 2.00 D, 0.05 ± 0.40 D, and 0.01 ± 0.35 D, while mean cycloplegic M, J₀, and J₄₅ were −1.16 ± 2.17 D, 0.02 ± 0.40 D, and −0.01 ± 0.35 D. Significant differences were found between cycloplegic and non‐cycloplegic M (p = 0.009), whereas there were no significant differences between cycloplegic and non‐cycloplegic J₀ and J₄₅ (p = 0.486 and p = 0.594, respectively). The differences between cycloplegic and non‐cycloplegic M were statistically significant in the four to six years group (p = 0.002) and seven to 11 years group (p = 0.023), whereas there was no significant difference between cycloplegic and non‐cycloplegic M in the 12 to 16 years group (p = 0.151). The proportion of myopia decreased from 78.1 per cent before cycloplegia to 71.4 per cent after cycloplegia, while the proportion of hyperopia increased from 12.1 per cent before cycloplegia to 21.4 per cent after cycloplegia.

Conclusion

Non‐cycloplegic auto‐refraction is found to be inaccurate and not suitable for studies of refractive error in Chinese children.

Cohort study with 4-year follow-up of myopia and refractive parameters in primary schoolchildren in Baoshan District, Shanghai

Importance

Cohort studies could not only reveal associations between change of refractive components and onset/progression of myopia, but also risk factors, which is important for understanding mechanism and providing strategies.

Background

Prevalence of myopia is high in Shanghai, being reported to be 52.2% in children aged 10 years old.

Design

Cohort study.

Participants

A total of 1856 students from six randomly selected primary schools in Baoshan District, Shanghai.

Methods

Children underwent comprehensive ocular measurement, including axial length (AL), corneal curvature radius and cycloplegic auto‐refraction. Questionnaires about eye usage time were collected. Grade 1 students were followed for 4 years, and grade 2 and 3 students for 2 years.

Main Outcome Measures

(i) Change of spherical equivalent (SE) and AL and (ii) risk factors for progression and incidence of myopia.

Results

The average 2‐year progress of SE was 0.91D, 0.91D and 1.11D for grade 1, 2 and 3, respectively, and the average elongation of AL was 0.70 mm, 0.64 mm and 0.71 mm, respectively. Only parental myopia, but not near work time, near work diopter time, outdoor activity time or attending tutoring classes, was associated with myopia incidence and progression in the present population. Using baseline SE could be a simple and effective indicator for myopia prediction.

Conclusions and Relevance

Incidence and progression of myopia is relatively high in schoolchildren in Shanghai compared with children of Western countries, East Asia and other parts of China. Effective strategies to control myopia prevalence are in urgent need.

Comparison of noncycloplegic and cycloplegic autorefraction in categorizing refractive error data in children

Purpose

To systematically analyse the differences between cycloplegic and noncycloplegic refractive errors (RE) in children and to determine if the predictive value of noncycloplegic RE in categorizing RE can be improved.

Methods

Random cluster sampling was used to select 6825 children aged 4–15 years. Autorefraction was performed under both noncycloplegic and cycloplegic (induced with 1% cyclopentolate drops) conditions. Paired differences between noncycloplegic and cycloplegic spherical equivalent (SE) RE were determined. A general linear model was developed to determine whether cycloplegic SE can be predicted using noncycloplegic SE, age and uncorrected visual acuity (UCVA).

Results

Compared to cycloplegia, noncycloplegia resulted in a more myopic SE (paired difference: −0.63 ± 0.65D, 95% CI: −0.612 to −0.65D, 6017 eligible right eyes) with greater differences observed in younger participants and in eyes with more hyperopic RE and smaller AL. Using raw noncycloplegic data resulted in only 61% of the eyes being correctly classified as myopic, emmetropic or hyperopic. Using age and uncorrected VA in the model, the association improved and 77% of the eyes were classified correctly. However, predicted cycloplegic SE continued to show large residual errors for low myopic to hyperopic RE. Applying the model to only those eyes with uncorrected VA <6/6 resulted in an improvement (R² = 0. 93), with 80% of the eyes correctly classified. A higher VA cut‐off (i.e., ≤6/18) resulted in 97.5% of eyes classified correctly.

Conclusion

Noncycloplegic assessment of RE in children overestimates myopia and results in a high error rate for emmetropic and hyperopic RE. Adjusting for age and applying uncorrected VA cut‐offs to noncycloplegic assessments improves detection of myopic RE and may help in identifying myopic RE in situations where cycloplegia is not available but does not help in identifying the magnitude of refractive error and therefore is of limited value.

Design and methodology of the Shanghai child and adolescent large-scale eye study (SCALE)

Importance

Nearly half of children suffering vision impairment reside in China with myopia accounting for the vast majority.

Background

To describe the design and methodology of the Shanghai Child and Adolescent Large‐scale Eye Study (SCALE).

Design

The SCALE was a city wide, school‐based, prospective survey.

Participants

Children and adolescents aged 4–14 years from kindergarten (middle and senior), primary schools and junior high schools of all 17 districts and counties of the city of Shanghai, China were examined in 2012–2013.

Methods

Each enrolled child underwent vision assessment (distance visual acuity; uncorrected and with corrective device if worn) and their parent/carer completed a questionnaire designed to elicit risk factors associated with myopia. Additionally, non‐cycloplegic autorefraction and ocular axial length was measured in a subset of the larger sample.

Main Outcome Measures

Prevalence and the associated factors of vision impairment, myopia and high myopia in Shanghai.

Results

In 2012–2013, a total of 910 245 of the eligible 1 196 763 children and adolescents identified from census (76%, mean age 9.0 ± 2.7 years [4–14 years]) were enrolled with visual acuity screened in the city of Shanghai. Of these, 610 952 children (67% of the entire sample) underwent non‐cycloplegic autorefraction and 219 188 (24% of the entire sample) had both non‐cycloplegic autorefraction and axial length measurements.

Conclusions and Relevance

The study results will provide insights on the burden of vision impairment, myopia and high myopia in children and adolescents in a metropolitan area of China, and contribute to the policies and strategies to address and limit the burden.

CHOROIDAL THICKNESS IN HEALTHY CHINESE CHILDREN AGED 6 to 12: The Shanghai Children Eye Study

PURPOSE

To explore the characteristics of choroidal thickness (ChT) in Chinese children.

METHODS

A total of 144 healthy children, aged 6 years to 12 years old, were enrolled in the study. The ChT of subfovea and peripheral locations 0.5, 1.5, and 2.5 mm away from the fovea were evaluated by enhanced depth imaging optical coherence tomography. The association between subfoveal ChT and systemic, as well as ocular factors, including age, sex, height, weight, body mass index, axial length, refractive error, intraocular pressure, preterm history, and the refractive status of parents were studied.

RESULTS

The mean subfoveal ChT was 302 ± 63 μm. In the nasal, superior, and inferior areas, the ChT of locations closer to the fovea was thicker than those farther away from the fovea (all P < 0.05); however, ChT was not significantly different among different locations in the temporal area (P = 0.16). The ChT of the nasal quadrant was significantly thinner than that of other areas (P < 0.01). Subfoveal ChT decreased with age, axial length, preterm history, and increased with height. Sex was not statistically associated with subfoveal ChT.

CONCLUSION

In Chinese children, the ChT is thinnest in the nasal quadrant and thicker in central regions than in peripheral areas. The subfoveal ChT independently decreases with age, axial length, preterm history, and increases with height.

Corneal Thickness Profile and Associations in Chinese Children Aged 7 to 15 Years Old

Corneal thickness (CT) maps of the central (2-mm diameter), para-central (2 to 5-mm diameter), peripheral (5 to 6-mm diameter), and minimum (5-mm diameter) cornea were measured in normal Chinese school children aged 7 to 15 years old using Fourier-domain optical coherence tomography. Multiple regression analyses were performed to explore the effect of associated factors [age, gender, refraction, axial length and corneal curvature radius (CCR)] on CT and the relationship between central corneal thickness (CCT) and intraocular pressure (IOP). A total of 1228 eyes from 614 children were analyzed. The average CCT was 532.96 ± 28.33 μm for right eyes and 532.70 ±28.45 μm for left eyes. With a 10 μm increase in CCT, the IOP was elevated by 0.37 mm Hg, as measured by noncontact tonometry. The CT increased gradually from the center to the periphery. The superior and superior nasal regions had the thickest CTs, while the thinnest points were primarily located in the inferior temporal cornea. The CCT was associated with CCR (p = 0.008) but not with gender (p = 0.075), age (p = 0.286), axial length (p = 0.405), or refraction (p = 0.985). In the para-central region and the peripheral cornea, increased CT was associated with younger age, male gender, and a flatter cornea.

Axial length/corneal radius ratio: association with refractive state and role on myopia detection combined with visual acuity in Chinese schoolchildren

PURPOSE

To evaluate the association between the AL/CR ratio and refractive state and explore the effectiveness of this ratio in the assessment of myopia, especially when combined with uncorrected visual acuity in schoolchildren among whom myopia is common.

METHODS

Cross sectional study. 4686 children from 6 primary schools, aged from 6 to 12 years were selected using the clustered-stratified random sampling method. Uncorrected visual acuity (UCVA), axial length (AL), corneal radius of curvature (CR), and cycloplegic refraction were tested. Refraction was measured as the spherical equivalent (SE).

RESULTS

3922 children were included in the analysis. The mean AL/CR ratio was 2.973±0.002, increased with age, and different in gender. The coefficients of correlations of the SE with the AL/CR ratio, AL, and CR were -0.811, -0.657, and 0.095, respectively. Linear regression showed a 10.72 D shift towards myopia with every 1 unit increase in the AL/CR ratio (P<0.001, r2 = 66.4%). The estimated SE values obtained by substituting the AL/CR ratio and gender back to the regression model that were within a difference of ±0.50 D in ATE/LER (allowable total error and limits for erroneous results) zones compared to the actual measured values was 51%. The area under the ROC curve of the AL/CR ratio, AL, and UCVA for myopia detection were 0.910, 0.822, and 0.889, respectively, and the differences between each pair were statistically significant (P<0.01). At a specificity of 90%, the sensitivities were 72.98%, 50.50%, 71.99%, and 82.96%, respectively, for the AL/CR ratio, AL, UCVA, and the combination of the AL/CR ratio and UCVA.

CONCLUSIONS

The AL/CR ratio was found to explain the total variance in SE better than AL alone. The effectiveness of the AL/CR ratio was statistically significantly better than UCVA for detecting myopia in children, and combining the two produced increased sensitivity without significantly decreasing specificity.

Screening for significant refractive error using a combination of distance visual acuity and near visual acuity

PURPOSE

To explore the effectiveness of using a series of tests combining near visual acuity (NVA) and distance visual acuity (DVA) for large-scale screenings for significant refractive error (SRE) in primary school children.

METHOD

Each participant underwent DVA, NVA and cycloplegic autorefraction measurements. SREs, including high myopia, high hyperopia and high astigmatism were analyzed. Cycloplegic refraction results were considered to be the gold standard for the comparison of different screening measurements. Receiver-operating characteristic (ROC) curves were constructed to compare the area under the curve (AUC) and the Youden index among DVA, NVA and the series combined tests of DVA and NVA. The efficacies (including sensitivity, specificity, positive predictive value, and negative predictive value) of each test were evaluated. Only the right eye data of each participant were analysed for statistical purpose.

RESULT

A total of 4416 children aged 6 to 12 years completed the study, among which 486 students had right eye SRE (SRE prevalence rate = 11.01%). There was no difference in the prevalence of high hyperopia and high astigmatism among different age groups. However, the prevalence of high myopia significantly increased with the age (χ² = 381.81, p<0.01). High hyperopia was the biggest SRE factor associated with amblyopia（p＜0.01，OR = 167.40, 95% CI: 75.14∼372.94). The DVA test was better than the NVA test for detecting high myopia (Z = 2.71, p<0.01), but the NVA test was better for detecting high hyperopia (Z = 2.35, p = 0.02) and high astigmatism (Z = 4.45, p<0.01). The series combined DVA and NVA test had the biggest AUC and the highest Youden Index for detecting high hyperopia, myopia, astigmatism, as well as all of the SREs (all p<0.01).

CONCLUSION

The series combined DVA and NVA test was more accurate for detecting SREs than either of the two tests alone. This new method could be applied to large-scale SRE screening of children, aged 6 to 12, in areas that are less developed.