Ophthalmological data on 4.5- to 7-year-old Danish children

Vision screening and refraction of Greenlandic schoolchildren

PURPOSE

To estimate the prevalence of amblyopia and refractive errors among 6-year-old children in Greenland and to assess the impact of incorporating autorefraction, stereoacuity and near visual acuity testing into vision screening.

METHODS

In this cross-sectional study, 517 children (238 girls and 279 boys) from 21 locations in Greenland were screened using HOTV charts for distance and near visual acuity (VA), stereoacuity test and non-cycloplegic autorefraction. Referral criteria for further ophthalmological examination included a VA of ≥0.2 logMAR on the worse-seeing eye or an interocular VA difference of ≥2 lines.

RESULTS

Initial screening identified amblyopia (defined as VA of ≥0.3 logMAR) in 7% (unilateral) and 3% (bilateral) of children. However, subsequent ophthalmological examinations confirmed amblyopia in under 40% of referrals. Significant interocular VA differences were found in 9%. The prevalence of refractive errors at the screening was 3% for myopia (≤-0.5 dioptres), 10% for hyperopia (>+2.0 dioptres) and 14% for astigmatism (≤-1.00 dioptres), while the corresponding prevalences at the ophthalmological examination were 4% for myopia, 8% for hyperopia and 6% for astigmatism. Combining screening measurements increased the positive predictive values, thereby enhancing screening accuracy. Specifically, the incorporation of autorefraction or stereoacuity with distance VA demonstrated to be the most effective combination. Six percent of the children were prescribed glasses after the screening procedure.

CONCLUSION

This study provides the first visual profile of Greenlandic schoolchildren. Incorporating autorefraction, stereoacuity and near visual acuity in vision screenings enhanced the efficacy of detection of vision anomalies. Although this may lead to more false positives, accurate screening is crucial in regions with limited ophthalmological resources.

Refraction and ocular biometric parameters of preschool children in the Beijing whole childhood eye study: the first-year report

BACKGROUND

Prevention of myopia should begin before school age. However, few population-based cohort studies have investigated refractive status in preschool children with cycloplegia. This study aimed to investigate the post-COVID-19 refraction and ocular biometric parameters of preschool children in Beijing Tongzhou District.

METHODS

A population-based cohort study of kindergarten children in Tongzhou District, Beijing, commenced in November 2021. The present study reports data from the first year of the aforementioned population-based study. We selected children aged 3-6 years from nine kindergartens. Biometric parameters, including axial length (AL), anterior chamber depth (ACD), and corneal radius of curvature (CR), were collected before cycloplegia. Cycloplegic refraction was also measured. The spherical equivalent (SE), lens power (LP), and AL-to-CR ratio were calculated. Multiple linear regression analysis was used to analyse the correlation between refraction and ocular biometric parameters.

RESULTS

A total of 1,505 children completed the examination, and a mean SE of 1.24 ± 0.91 D was found. The overall prevalence of myopia was 1.93%. The mean AL, ACD, CR, LP, and AL-to-CR ratio were 22.24 ± 0.70 mm, 3.28 ± 0.26 mm, 7.77 ± 0.26 mm, 26.01 ± 1.56 D, and 2.86 ± 0.07, respectively. Longer AL, deeper ACD, larger AL-to-CR ratio, and lower LP were associated with older age; the CR was not significantly different among different ages. In the multiple linear regression analysis, after adjusting for sex and age, the model that included AL, CR, and LP explained 87% of the SE variation. No differences were observed in the prevalence of myopia or the SE in this particular age range.

CONCLUSION

The findings of this study suggest that a large proportion of preschool children in Beijing are mildly hyperopic, with a considerably low prevalence of myopia. In preschool children, refractive development was found to present mild hyperopia rather than emmetropia or myopia, a phenomenon that is characteristic of this age range.

Differential compensatory role of internal astigmatism in school children and adults: The Hong Kong Children Eye Study

BACKGROUND

To compare the prevalence of refractive (RA), corneal (CA), and internal astigmatism (IA) in Hong Kong children and adults and evaluate the role of IA in compensating for total astigmatism and its relations to myopic traits.

METHODS

The Hong Kong Children Eye Study is a population-based cross-sectional study. Totally 3704 school children (mean age 7.5 ± 1.0 years) and 5577 adults (mean age 41.1 ± 7.5 years), who were their parents, were recruited. Cycloplegic and non-cycloplegic refractive cylinders were obtained from children and adults, respectively. Spearman correlation was applied to detect associations between astigmatism, ocular biometrics, refraction, and lens power. Astigmatism compensation factor (CF) was derived from the power vector analysis J0 and J45.

RESULTS

The prevalence of RA (≤-1.0 D), CA (≥+1.0 D) and IA (≥+1.0 D) was 21.9%, 63.9%, and 9.9% in children, and 30.9%, 39.5%, and 23.7% in adults respectively. The mean RA, CA and IA values in children and adults were -0.69 ± 0.66 D, +1.14 ± 0.61 D, +0.62 ± 0.32 D, and -0.80 ± 0.74 D, +0.97 ± 0.69 D, and +0.76 ± 0.43 D, respectively. In adults and children, IA was negatively correlated with axial length (p < 0.0001), but positively correlated with spherical values and equivalent (p < 0.0001), suggesting an association of astigmatism with myopic traits. A greater proportion of children exhibited compensation by IA than adults in J0 (86.6% vs. 66.0%, p < 0.0001) and J45 components (55.5% vs. 41.7%, p < 0.0001).

CONCLUSIONS

Chinese children in Hong Kong exhibit a higher prevalence of RA and CA than in other cities. Children displayed a greater compensation by IA than adults, suggesting an age-related attenuation of IA compensation. IA is associated with myopic traits.

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.

Refractive development I: Biometric changes during emmetropisation

PURPOSE

Although there are many reports on ocular growth, these data are often fragmented into separate parameters or for limited age ranges. This work intends to create an overview of normal eye growth (i.e., in absence of myopisation) for the period before birth until 18 years of age.

METHODS

The data for this analysis were taken from a search of six literature databases using keywords such as "[Parameter] & [age group]", with [Parameter] the ocular parameter under study and [age group] an indication of age. This yielded 34,409 references that, after screening of title, abstract and text, left 294 references with usable data. Where possible, additional parameters were calculated, such as the Bennett crystalline lens power, whole eye power and axial power.

RESULTS

There were 3422 average values for 17 parameters, calculated over a combined total of 679,398 individually measured or calculated values. The age-related change in refractive error was best fitted by a sum of four exponentials (r²  = 0.58), while all other biometric parameters could be fitted well by a sum of two exponentials and a linear term ('bi-exponential function'; r² range: 0.64-0.99). The first exponential of the bi-exponential fits typically reached 95% of its end value before 18 months, suggesting that these reached genetically pre-programmed passive growth. The second exponentials reached this point between 4 years of age for the anterior curvature and well past adulthood for most lenticular dimensions, suggesting that this part represents the active control underlying emmetropisation. The ocular components each have different growth rates, but growth rate changes occur simultaneously at first and then act independently after birth.

CONCLUSIONS

Most biometric parameters grow according to a bi-exponential pattern associated with passive and actively modulated eye growth. This may form an interesting reference to understand myopisation.

Relatively Stable Prevalence of Myopia among Swedish Children Aged 4 to 7 Years between 2015 and 2020

SIGNIFICANCE

The global increase of myopia has caused a lot of debate the last years. Previous research of myopia in the Nordic population has shown diverse results, and only a few Swedish studies have been published in the subject the last two decades.

PURPOSE

This study aimed to analyze trends in the prevalence of myopia in a population of Swedish children.

METHODS

A retrospective analysis of medical records for children between 4 and 7 years of age in a region in Sweden was performed. The inclusion criterion was a first glasses prescription for myopia between 2012 and 2020. Children with other eye diseases or syndromes affecting the eye and vision were excluded. Age, sex, uncorrected visual acuity, and cycloplegic refractive values were extracted. The number of myopic children was compared with population data to calculate incidence and estimate prevalence.

RESULTS

During the study period, 427 children between 4 and 7 years old in an average population of 17,200 children were prescribed glasses for myopia. The incidence for myopia increased from 0.11% in 2012 to 0.39% in 2020 ( P < .05). In 2015 to 2020, the prevalence of myopia for the same age group increased from 0.5 to 1.2% ( P < .05). Linear regression of the prevalence of myopia showed a significant increase in the age group of 7 years ( β = 0.2%, R2 = 0.82, P ≤ .05).

CONCLUSIONS

This study found a relatively stable prevalence of myopia among Swedish children aged 4 to 7 years between 2015 and 2020. The prevalence of 1.6% among 7-year-old children is not higher than in previous Scandinavian studies.

The Global Prevalence of Amblyopia in Children: A Systematic Review and Meta-Analysis

Epidemiological data about the prevalence of amblyopia around the world vary widely among regions and periods. This meta-analysis aimed to determine the global prevalence of amblyopia in children. PubMed, Embase, and the Cochrane Library were searched for prevalence studies published up to 5 November 2021. The outcome was the prevalence of amblyopia, analyzed as pooled estimates with 95% confidence intervals (CI). A total of 97 studies were included, including 4,645,274 children and 7,706 patients with amblyopia. The overall worldwide pooled prevalence of amblyopia was 1.36% (95%CI: 1.27-1.46%). The prevalence of amblyopia was higher in males (1.40%, 95%CI: 1.10-1.70%) than in females (1.24%, 95%CI: 0.94-1.54%) (OR = 0.885, 95%CI: 0.795-0.985, P = 0.025). The results of the meta-regression analysis showed that there were no significant associations between the prevalence of amblyopia and geographical area, publication year, age, sample size, and whether it was carried out in a developed or developing country (all P > 0.05). Begg's test (P = 0.065) and Egger's test (P < 0.001) showed that there was a significant publication bias in the prevalence of amblyopia. In conclusion, amblyopia is a significant vision problem worldwide, and public health strategies of early screening, treatment, and management are important.

Refractive errors in a large dataset of French children: the ANJO study

Undetected refractive errors (REs) in children can lead to irreversible vision loss. This study aimed to show the proportions of REs in French children using cycloplegic refraction. Multicentre cross-sectional retrospective study including children with cycloplegic refraction and without associated ocular conditions from 2015 to 2018 in French eye clinics. The following data were collected: age, symptoms of eye strain, best-corrected visual acuity (BCVA), cycloplegic refraction. The analysis included 48,163 children (mean age: 7.75 years, range: 2 to 12 years). The proportion of each RE was as follows: emmetropia (− 0.50 < Spherical Equivalent (SE) ≤  + 2.0; 58.3%), hyperopia (+ 2.0 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$<$$\end{document}< SE \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤+5; 17.2%), myopia (− 6 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤ SE \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤− 0.50; 15.5%), high myopia (SE < − 6; 0.5%), high hyperopia (SE >  + 5; 3.6%), mixed astigmatism (4.9%). Anisometropia (SE difference ≥ 1.5) was found in 5.0%. Functional amblyopia in children attending primary school (aged over 6 years) was encountered in 2.7%. Symptoms of eye strain were frequent (70%) but not specific to any RE. REs are frequently found in French children and may remain undetected in the absence of symptoms of eye strain. Few studies have investigated REs in children using cycloplegic refraction, which has been shown to be the gold standard for RE assessment.

Stereoacuity and its determinants in 7-year-old children: the Lhasa Childhood Eye Study

PURPOSE

To explore the distribution of stereoacuity and to examine its determinants in school-age children in Tibetan plateau, Southwest China.

METHODS

This is the cross-sectional part of a school-based cohort study of 7-year-old children in Lhasa, Tibet Autonomous Region, Southwest China. Children in first year of primary school were invited to undergo a comprehensive examination, including height, weight, visual acuity, cycloplegic autorefraction (1% cyclopentolate), anterior segment, cover and uncover test, and stereoacuity (Titmus Stereo Test).

RESULTS

A total of 1833 eligible subjects were included, with a mean age of 6.82 ± 0.46 years. Mean stereoacuity was 1.78 ± 0.21 in log units (median: 60 arcsec). Children with stereoacuity equal to 40 arcsec and stereoacuity worse than 100 arcsec accounted for 29.24% and 8.18% of the cohort, respectively. Tibetan ethnicity (OR = 1.98; 95%CI, 1.30-3.03), astigmatism (OR = 1.65; 95%CI, 1.26-2.17), strabismus (OR = 2.92; 95%CI, 1.38-6.18), and amblyopia (OR = 3.77; 95%CI, 1.14-12.49) were risk factors for normal stereoacuity (= 40 arcsec). Shorter height, younger age, strabismus, and worse BCVA (P < 0.05 for all) were both related to lower stereoacuity in Spearman correlation analysis and associated with lower stereoacuity in multivariate regression analysis.

CONCLUSION

Stereoacuity maturation does not appear fully completed in 7-year-old children, while few children present stereoacuity worse than 100 arcsec (8.18%). Lower stereoacuity was associated with younger age, shorter height, strabismus, and lower best-corrected visual acuity.

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.

[Visual acuity in German preschool children-results of a cross-sectional study]

Hintergrund

Im Rahmen der kinderärztlichen Vorsorgeuntersuchungen U1 bis U9 von der Geburt bis zum Beginn des sechsten Lebensjahres wird unter anderem das Sehvermögen getestet – eine augenärztliche Vorsorgeuntersuchung im Kindesalter gibt es in Deutschland nicht. Diese Studie untersucht, ob eine Teilnahme an der U8 (am Ende des vierten Lebensjahres) und der U9 (zu Beginn des sechsten Lebensjahres) mit Sehschärfeergebnissen assoziiert ist, die im Rahmen der Schuleingangsuntersuchungen (SEU) erhoben werden.

Methoden

Ausgewertet wurden Daten der SEU des Landes Rheinland-Pfalz der Einschulungsjahrgänge 2009/2010 bis 2014/2015. In diesen Jahrgängen wurde die Sehschärfe mittels Rodenstock-Sehtestgerät (E-Haken; Rodenstock Instrumente GmbH, Ottobrunn, Deutschland) und eigener Korrektur geprüft. Festgehalten wurden reduzierte Sehschärfen von <0,7. Der Zusammenhang zwischen der Teilnahme an den Vorsorgeuntersuchungen U8 bzw. U9 und dem Vorliegen einer ein- und beidseitigen Sehschärfe <0,7 bei SEU wurde mithilfe von multipler logistischer Regressionsanalyse untersucht und für wichtige Störgrößen adjustiert.

Ergebnisse

Daten von 189.704 Kindern (91.041 Mädchen und 98.663 Jungen) aus 35 von 36 Landkreisen konnten eingeschlossen werden. Eine Sehschärfe <0,7 wurde bei 8416 Kindern (4,4 %) ermittelt, in beiden Augen bei 4345 (2,3 %) Kindern. Die Teilnahmequote an der U8 bzw. U9 betrug 93,9 % bzw. 93,3 %. Es bestand eine negative Assoziation zwischen der Teilnahme an der U8 bzw. U9 und einem ein- oder beidseitigen SEU-Visus <0,7 (adjustierte OR: 0,68; 95 %-KI: 0,61–0,75; p < 0,01; N = 124.467/adjustierte OR: 0,57; 95 %-KI: 0,51–0,65; p < 0,01; N = 121.496).

Schlussfolgerungen

Es zeigt sich ein hoher Anteil an Kindern mit verminderter Sehschärfe bei der Schuleingangsuntersuchung. Kinder, die in der U8 und U9 untersucht worden waren, hatten eine bessere Chance für eine gute Sehschärfe bei der Schuleingangsuntersuchung.

Ametropia and Emmetropization in CNGB3 Achromatopsia

Purpose

Emmetropization is the process of adjusting ocular growth to the focal plane in order to achieve a clear image. Chromatic light may be involved as a cue to guide this process. Achromats are color blind and lack normal cone function; they are often described as being hyperopic, indicating a failure to emmetropize. We aim to describe the refraction and refractive development in a population of genetically characterized achromats.

Methods

Refractive error data were collected retrospectively from 28 medical records of CNGB3 c.1148delC homozygous achromats. The distribution of spherical equivalent refractive error (SER) and spherical error was analyzed in adults. The refractive development in children was analyzed by documenting astigmatic refractive error and calculating median SER in 1-year age groups and by analyzing the individual development when possible.

Results

The distribution of SER and spherical error resembled a Gaussian distribution, indicating that emmetropization was disturbed in achromats, but we found indication of some decrease in SER during the first years of childhood. The prevalence of refractive errors was high and broadly distributed. Astigmatic refractive errors were frequent but did not seem to increase with age.

Conclusions

Refractive development in achromats is more complicated than a complete failure to emmetropize. The spread of refractive errors is larger than previously documented. Results presented here support the theory that chromatic cues and cone photoreceptors may play a role in emmetropization in humans but that it is not essential.

Headache and musculoskeletal pain in school children are associated with uncorrected vision problems and need for glasses: a case-control study

Musculoskeletal pain and headache are leading causes of years lived with disability, and an escalating problem in school children. Children spend increasingly more time reading and using digital screens, and increased near tasks intensify the workload on the precise coordination of the visual and head-stabilizing systems. Even minor vision problems can provoke headache and neck- and shoulder (pericranial) pain. This study investigated the association between headaches, pericranial tenderness, vision problems, and the need for glasses in children. An eye and physical examination was performed in twenty 10–15 year old children presenting to the school health nurse with headache and pericranial pain (pain group), and twenty age-and-gender matched classmates (control group). The results showed that twice as many children in the pain group had uncorrected vision and needed glasses. Most children were hyperopic, and glasses were recommended mainly for near work. Headache and pericranial tenderness were significantly correlated to reduced binocular vision, reduced distance vision, and the need for new glasses. That uncorrected vision problems are related to upper body musculoskeletal symptoms and headache, indicate that all children with these symptoms should have a full eye examination to promote health and academic performance.

Prevalence of Heterophoria in Tibetan Grade-One Students: The Lhasa Childhood Eye Study

INTRODUCTION

The study aims to explore the prevalence of heterophoria and associate factors in Tibetan grade-one students.

METHODS

The Lhasa Childhood Eye Study (LCES) is a school-based cohort study. 1942 grade-one students from 7 elementary schools were randomly sampled by stratified cluster sampling. Ocular examinations were performed in participants, including ocular motility, distance and near visual acuity, cycloplegic autorefraction, and stereoacuity. The near (33 cm) and distance (6 m) fixation cover test was used to differentiate orthophoria, heterophoria, and heterotropia, and the magnitude of the phoria was measured by the Maddox rod and prisma.

RESULTS

Of 1856 grade-one students completing all the ocular examinations, 1852 participants finished the ocular alignment test. The mean age was 6.82 ± 0.46 years (range 6∼10 years); 981 (52.97%) were males, and 871 (47.03%) were females. The prevalence of phoria was 22.89% (n = 424). At distance fixation, the prevalence of heterophoria, exophoria, and esophoria was 4.64%, 4.21%, and 0.43% separately, while at near fixation, the prevalence was 22.73%, 22.35%, and 0.38%. No vertical phoria was detected. The mean magnitude of heterophoria at near and distance fixation was -7.63 ± 5.15 PD (exo: -7.83 ± 4.91 PD, eso: +5.67 ± 3.61 PD) and -4.84 ± 5.94 PD (exo: -6.26 ± 4.20 PD, eso: +8.13 ± 3.04 PD). The prevalence of esophoria was associated with hyperopia (OR = 6.38, 95% CI: 1.15-35.28, P = 0.03; OR = 5.42, 95% CI: 1.04-28.24, P = 0.04) and amblyopia (OR = 16.02, 95% CI: 1.81∼141.96, P = 0.01; OR = 11.37, 95% CI: 1.34∼96.52, P = 0.03) at near and distance fixation. The prevalence of exophoria was associated with myopia at near fixation (OR = 2.43, 95% CI: 1.47-4.00, P<0.01). In the near heterophoria group, the proportion of children with abnormal stereoacuity was 23.26% (n = 97), significantly higher (χ 2 = 5.70, P = 0.017) than that in orthophoria (17.99%, n = 244).

CONCLUSIONS

In Lhasa, grade-one pupils have a lower prevalence of heterophoria. Near exophoria was associated with myopia, while esophoria was related to hyperopia and amblyopia both near and distance. Heterophoria may be one of the affected factors for reducing stereoacuity.

Impaired visual acuity caused by uncorrected refractive errors and amblyopia in a German paediatric cohort

PURPOSE

This study describes the prevalence of visual impairment caused by uncorrected distance refractive error and the spectacle coverage in a large cohort of German children and adolescents. Furthermore, we determined the prevalence of amblyopia and amblyopia treatment.

METHODS

Optometrists carried out visual acuity (VA) testing, non-cycloplegic autorefraction, VA retesting with the refractive correction obtained by autorefraction, and if necessary subjective refraction and cover-test in 1,874 subjects (901 girls/973 boys), aged 3 to 16 years. Additionally, a questionnaire on the history of previous eye care was completed.

RESULTS

Distance visual impairment (VI) with VA worse than 6/18 Snellen in the better eye was present in 0.5% (95% confidence interval [95% CI]: 0.2% to 0.9%) of children. Logistic regression showed a significant positive association between VI and older age (OR = 1.21, P = 0.03). Gender differences were not found (P = 0.77). The spectacle coverage of all participants was 74.8% (95% CI: 65.2% to 82.8%). Amblyopia was found in 29 participants (1.5%; 95% CI: 1.0% to 2.2%) with no age or sex differences. The causes of unilateral amblyopia (27 cases, 93.1%) were anisometropia in 55.6% of children, strabismus in 25.9% and the combination of these factors in 18.5%. All children with bilateral amblyopia (2 cases, 6.9%) showed bilateral high ametropia. We observed 15 children with current amblyopia, who had been treated with occlusion therapy in the past (62.2%; 95% CI: 42.7% to 83.6%).

CONCLUSIONS

The prevalence of impaired VA caused by uncorrected refractive error and amblyopia is comparable with previous studies conducted in urban areas worldwide. Adding the measurement of refractive error to existing medical check-ups, possibly using autorefraction, would be desirable.

Prevalence, incidence and risk factors of strabismus in a Chinese population-based cohort of preschool children: the Nanjing Eye Study

AIMS

To evaluate the prevalence, incidence and their related risk factors of strabismus among preschool children in China.

METHODS

Children born between September 2011 and August 2012 in Yuhuatai District of Nanjing were invited to participate in the Nanjing Eye Study for a comprehensive eye examination annually since 2015. The data presented in this paper were obtained from 2015 to 2017, when these children grew from the age of 3 to 5 years. Eye examinations included visual acuity, anterior segment, posterior segment, refraction, and ocular alignment and motility. Risk factors were evaluated using univariable and multivariable logistic regression models for prevalent and incident strabismus.

RESULTS

In 2015, a total of 2018 children (87.7% response rate) of 2300 eligible preschoolers completed the baseline eye examination when they were 3 years old. Among the 2018 participants, 50 had strabismus (prevalence rate, 2.48%). In multivariable analysis, prevalent strabismus was independently associated with parental strabismus history (OR=11.60, p<0.001), hyperopia (OR=6.22, p<0.001), prematurity (OR=3.07, p=0.01) and astigmatism (OR=2.15, p=0.04). Among 1766 children followed up for 2 years, 63 developed strabismus (annual incidence rate, 1.78%), of whom 57 had exotropia and 6 had esotropia. In multivariable analysis, incident strabismus was significantly associated with parental strabismus history (OR=5.55, p=0.04) and prematurity (OR=3.77, p<0.001).

CONCLUSIONS

In this population-based cohort study, we found a higher incidence of strabismus and a higher exotropia:esotropia ratio than previous studies in preschool children. Parental strabismus history and prematurity were associated with a higher risk for both prevalent and incident strabismus.

High prevalence of myopia in children and their parents in Hong Kong Chinese Population: the Hong Kong Children Eye Study

PURPOSE

To determine the myopia prevalence in Hong Kong Chinese children and their parents.

METHODS

It was a population-based cross-sectional study. A total of 4257 children aged 6-8 years, and 5880 parents were recruited in the Hong Kong Children Eye Study. Cycloplegic autorefraction was measured for children; and non-cycloplegic autorefraction for parents. Parental educational level, children's outdoor time, and near work were collected by validated questionnaires.

RESULTS

In children aged 6-8 years, 25.0% were myopic, and among them, 12.7% for the 6-year-olds, 24.4% for the 7-year-olds and 36.1% for the 8-year-old. About 0.7% of children aged 8 years were high myopia. In all age groups, boys (their myopia rate: 13.9% at 6 years, 26.7% at 7 years, and 38.3% at 8 years) were more myopic than girls (11.3% at 6 years, 22.0% at 7 years, 33.4% at 8 years). Among parents, 72.2% were myopic (mother, 73.2%; father, 70.7%) and 13.5% high myopia (mother, 12.8%; father, 14.5%). It was observed that prevalence decreased with ages and increased with education level.

CONCLUSION

There is a strikingly high prevalence of myopia in Hong Kong children aged 6-8, much higher than that of other regions of China. Of note, the prevalence of children was similar to that in 15 years ago. Furthermore, the myopia prevalence of parents is high, and it had already increased in this cohort. Prevention of childhood myopia is important, likewise for visual complications from high myopia in adults.

Prevalence of heterophoria in a population of school children in central China: the Anyang Childhood Eye Study

AIM

To investigate the prevalence of heterophoria and the relationship between heterophoria and refractive error in a school-based study conducted in central China.

METHODS

A total of 2363 7^th-grade children were recruited into the cross-sectional school-based Anyang Childhood Eye Study (ACES) by cluster sampling method. Heterophoria was examined using alternate cover and cover-uncover testing. The Maddox rod and prism test were conducted at 33 cm and 6 m distance fixation. Uncorrected viual acuity (UCVA) and best-corrected viual acuity (BCVA) were recorded as logarithm of the minimum angle of resolution (logMAR) with cycloplegic autorefraction by administrating of Mydrin-P and 1.0% cyclopentolate. Hyperopia was defined as the spherical equivalent (SE) refraction of +0.50 D or greater, and higher hyperopia was defined as +2.00 D or greater. Emmetropia was defined as the SE refraction in the range of -0.49 to +0.49 D, and myopia was in the SE refraction range from -0.50 D to less.

RESULTS

Totally 2260 students in grade 7 were examined. Response rate among eligible children was 95.64%. Totally 486 children, 22.66% of the population, were diagnosed with heterophoria in which 479 were diagnosed with exophoria at near distance, and 6 with esophoria. Totally 89 (4.15%) children were diagnosed with heterophoria in which 82 had exophoria, and 7 had esophoria at far distance. Exophoria was common at near fixation (22.33%). Myopia was examined to be related to exophoria at near distance (OR 3.03, 95%CI 2.33-3.95) and far distance fixation (OR 1.90, 95%CI 1.09-3.32).

CONCLUSION

Exophoria is a predominant heterophoria for 7^th-grade junior school in central China. Significant associations are discovered between heterophoria and refractive error. Hyperopia is associated with esophoria, and myopia is associated with exophoria.

No Benefit of a Pediatric Screening in Discovering Reduced Visual Acuity in Children: Experiences from a Cross-Sectional Study in Germany

BACKGROUND

The newly introduced German pediatric screening examination at the end of the third year of life (U7a) incorporates visual function testing in particular; there is no ophthalmic screening during childhood in Germany. The purpose of this study is to investigate the relationship between participation in U7a and visual function at the preschool health examination (PHE) in the sixth year of life.

METHODS

This study evaluated PHE data from school enrollment years 2009/2010 to 2014/2015 of Rhineland-Palatinate, Germany. Visual acuity (VA) at PHE was assessed with Rodenstock visual acuity test device (tumbling E) wearing glasses if present. The relationship between participation in U7a and VA <0.7 at PHE was calculated for reduced monocular and binocular VA using multiple logistic regression adjusted for potential confounders.

RESULTS

Data from 189,704 children (91,041 girls) in 35 out of 36 districts were included. The first children to participate in U7a were enrolled in 2011/2012 school year. In total, 90,339 children (47.6%) had U7a before PHE, while 99,365 (52.4%) had not. VA <0.7 in at least one eye was measured at PHE in 8429 (4.4%) children, and in both eyes in 4345 (2.3%) children. Participation in U7a was not associated with VA <0.7 at PHE (odds ratio 0.99; 95% confidence interval: 0.94-1.04).

CONCLUSIONS

The proportion of children with VA <0.7 at PHE was high. No beneficial effect of newly introduced German U7a pediatric screening examination was found for reduced VA at PHE.

As-indicated versus routine vision screening of preterm children: a 17-year retrospective regional study

PURPOSE

To investigate outcomes of routine vision screening compared to as-indicated ophthalmological investigation of all children born preterm in a Danish region from 1997 to 2014.

METHODS

All children born preterm (gestation age < 32 weeks or birthweight < 1500 g) screened for retinopathy of prematurity (ROP) were divided into two groups. From 1997 to 2009, only children treated for ROP or referred for visual problems received ophthalmological investigation (as-indicated group). From 2010 to 2014, all ROP-screened infants were offered ophthalmological investigation at 6 months and 3 years of age (screening group).

RESULTS

A total of 560 children were included in the as-indicated period, 41 and 87 were referred for ophthalmological investigation at 6 months and 3 years, respectively. In the screening period, 295 children were included, 251 and 150 of whom underwent vision evaluation at 6 months and 3 years, respectively. Mean visual acuity was 4.1 cycles per degree with Teller acuity cards at 6 months and 0.78 decimal at 3 years. At 3 years, 2.7%(n = 11) in the as-indicated versus 3.5%(n = 10) screening group had visual acuity < 6/18 (p = 0.24). Cerebral palsy (n = 28) and epilepsy (n = 5) were significantly related to vision impairment (p = 0.001/0.006), while treated ROP was not (n = 13). Refractive error was common at 3 years (61%), especially astigmatism (50%). Gestational age, birthweight and ROP were not associated with vision impairment or refractive error.

CONCLUSION

Screening preterm children at 6 months and 3 years did not reveal more visually impaired children compared to examination when indicated.

The Danish Rural Eye Study: prevalence of strabismus among 3785 Danish adults - a population-based cross-sectional study

PURPOSE

To determine the prevalence of strabismus among Danish adults and to find the frequency of history of strabismus and strabismus surgery. Furthermore, to evaluate the prevalence of strabismus-associated amblyopia among participants with strabismus and to relate the results to the current national vision screening programme.

METHODS

In total, 3785 adults in the Danish Rural Eye Study underwent an interview regarding eye health, visual acuity measurement, Hirschberg test and retinal photography. Participants were categorized into groups based on their birth date in relation to the introduction of the national vision screening programme.

RESULTS

In total, the prevalence of strabismus was 1.1% (41/3785; 95% CI: 0.8-1.5); no differences were found in relation to gender or screening status. The prevalence of exotropia (XT) was 0.3% (12/3785; 95% CI: 0.2-0.6) and of esotropia (ET) 0.8% (29/3785; 95% CI: 0.5-1.1), resulting in an XT:ET ratio of 1:2.7. A history of strabismus was present in 4.6% (174/3785; 95% CI: 4.0-5.3), and a history of strabismus surgery was present in 0.8% (32/3785; 95% CI: 0.6-1.2) of the participants. Among participants with manifest strabismus, 24% had strabismus-associated amblyopia.

CONCLUSION

In this first European population-based study of strabismus prevalence in adults, the prevalence was similar to three out of five previous studies using cover test. The use of Hirschberg test may have led to an underestimation of the true prevalence. The prevalence was neither related to screening status nor gender. Our results are the first to display a predominance of ET among Caucasian Scandinavian adults.

Global prevalence of amblyopia and disease burden projections through 2040: a systematic review and meta-analysis

Purpose

Amblyopia is a leading cause of vision impairment among children and young adults. Individual studies showed significant variations in the prevalence of amblyopia in different regions and age groups. This study is to estimate the global prevalence of amblyopia by pooling its prevalence from the previous studies and to project the number of people affected through 2040.

Methods

We performed a systematic review and meta-analysis on the prevalence of amblyopia using data published before 20 October 2018. We estimated the prevalence rate of amblyopia and its 95% CI globally and by subgroups (eg, region and age). The prevalence data were applied to United Nations World Population Prospects to derive the projected number with amblyopia through 2040.

Results

A meta-analysis of 60 studies (1 859 327 subjects) showed that the pooled prevalence rate of amblyopia was 1.44% (95% CI 1.17% to 1.78%). Prevalences in Europe (2.90%) and North America (2.41%) were higher than in Asia (1.09%) and Africa (0.72%). The highest prevalence was found in subjects over 20 years old (3.29%). There was no difference in the prevalence between genders. We estimated 99.2 (95% CI 71.7 to 146.1) million people with amblyopia in 2019 worldwide, increasing to 175.2 (95% CI 81.3 to 307.8) million by 2030 and 221.9 (95% CI 83.7 to 429.2) million by 2040.

Conclusions

The amblyopia is becoming a significant vision problem worldwide. It is of great importance to design and implement amblyopia screening, treatment and related public health strategies.

Vision status of children aged 7-15 years referred from school vision screening in Norway during 2003-2013: a retrospective study

BACKGROUND

Undetected vision problems is an important cause of reduced academic achievement, performance in everyday life and self-esteem. This receives little attention in national health care services in Norway even though most of these vision problems are easily correctable. There are no published data on how many Norwegian schoolchildren are affected by correctable vision problems. This study aims to determine the vision status in primary and secondary schoolchildren referred from vision screening during the 10 year period of 2003-2013.

METHODS

Of the 1126 children (15%) aged 7-15 years referred to the university eye clinic by the school screening program, all 782 who attended the eye clinic were included in the study. Patient records were retrospectively reviewed with regard to symptoms, refractive error, best corrected visual acuity (BCVA) of logMAR, binocular vision, ocular health and management outcomes.

RESULTS

Previously undetected vision problems were confirmed in 650 (83%) of the children. The most frequent outcomes were glasses (346) or follow-up (209), but types of treatment modalities varied with age. Mean refractive errors were hyperopic for all age groups but reduced with age (ANOVA, p < 0.001). Overall, 51% were hyperopic, 32% emmetropic and 17% myopic. Refractive errors did not change across the decade (linear regression, all p > 0.05). Mean logMAR BCVAs were better than 0.0 and improved with age (ANOVA, p < 0.001). The most prevalent symptoms were headaches (171), near vision problems (149) and reduced distance vision (107).

CONCLUSIONS

The vision screening identified children with previously undetected visual problems. This study shows that the types of visual problems varied with age and that most problems could be solved with glasses. Our results stress the importance of regular eye examinations and that vision examinations should be included in primary health care services. Furthermore, there is a need for raised awareness among parents and teaching staff regarding vision problems in children.

Maternal smoking during pregnancy and the risk of strabismus in offspring: a meta-analysis

The effect of maternal smoking during pregnancy on strabismus in offspring remains unclear. We conducted a meta-analysis to summarize epidemiological evidences on the association between maternal smoking during pregnancy and the risk of offspring strabismus. Eligible studies were searched from the PubMed, Ovid, Embase and CNKI databases up to May 2018. The qualities of included articles were assessed with the Newcastle-Ottawa Scale and the assessment scale recommended by the Agency for Healthcare Research and Quality. Odds ratios (ORs) corresponding with its 95% confidence intervals (CIs) were pooled to estimate the effects of maternal cigarette smoking on the risk of offspring strabismus. Subgroup analyses and meta-regression were performed to explore the potential sources of heterogeneity. The Begg's test and Egger's test were used to assess the publication bias. Eleven articles involving 4,833 patients with strabismus were included. The pooled OR showed that maternal smoking during pregnancy was significantly associated with strabismus in offspring (OR = 1.46, 95% CI = 1.32-1.60). Compared with less than 10 cigarettes per day (OR = 1.17, 95% CI = 1.06-1.29), maternal smoking 10 cigarettes or more per day during pregnancy significantly increased the risk of offspring strabismus (OR = 1.79, 95% CI = 1.39-2.31). The risk of developing esotropia and exotropia for smoking pregnant women, respectively, increased by 65% (OR = 1.65, 95% CI = 1.31-2.09 and OR = 1.65, 95% CI = 1.24-2.19) than those who did not smoke during pregnancy. Additionally, the increased risk of maternity smoking associated with offspring strabismus was stable across all subgroup analyses. Overall, maternal smoking during pregnancy was associated with a significantly increased risk of offspring strabismus and the result was persistent in subgroup analyses, suggesting the importance in changing smoking habit or smoking cessation for women who are pregnant or preparing to.

Global and regional prevalence of strabismus: a comprehensive systematic review and meta-analysis

Purpose: Despite the importance of information on the prevalence of strabismus, which can be effective in planning preventive and curative services, no study has addressed its prevalence comprehensively. In this study, a systematic search was done to estimate the regional and global prevalence of strabismus in different age and sex groups and factors affecting prevalence heterogeneity. Methods: A comprehensive and systematic search was done in different international databases, including Web of Science, Scopus, PubMed, Embase, etc. to find published articles on the total prevalence of strabismus and the prevalence of exotropia and esotropia. A binomial distribution was used to calculate the prevalence and 95% confidence interval (CI). The Cochran's Q-test and I² were applied to evaluate heterogeneity and a random-effects model was used to assess the pooled prevalence. The Begg's test was administered to investigate publication bias and finally, a meta-regression method was applied to determine the factors affecting the heterogeneity among studies. Results: Of 7980 articles, 56 articles with a total sample size of 229,396 were analyzed. Many of these articles (n = 14) were from the Regional Office for the Americas. The estimated of pooled prevalence (95% CI) of any strabismus, exotropia, and esotropia was 1.93% (1.64-2.21), 1.23% (1.00-1.46), and 0.77% (0.59-0.95), respectively. The heterogeneity in prevalence of strabismus and its subtypes according to I² was above 95% (p value <.001 for all). Age had a direct effect on heterogeneity in the prevalence of exotropia (b: 3.491; p: 0.002). Moreover, WHO region had a significant direct effect on heterogeneity in the prevalence of strabismus (b: 0.482; p < .001) and esotropia (b: 0.168; p: 0.027), and publication year had a significant direct effect on heterogeneity in the prevalence of exotropia (b: 0.059; p: 0.045). Sample size and publication year did not have any association with strabismus nor with other variables. There was no publication bias according to the Begg's test. Conclusion: The prevalence of strabismus varies widely in the world. As for factors affecting heterogeneity in the prevalence of strabismus, the results showed that age affected heterogeneity in the prevalence of exotropia, WHO region affected heterogeneity in the prevalence of strabismus and esotropia, and publication year affected heterogeneity in the prevalence of exotropia. Information about the global prevalence of strabismus can help health care planners design interventions and prioritize resource allocation.

Visual acuity and amblyopia prevalence in 11- to 12-year-old Danish children from the Copenhagen Child Cohort 2000

PURPOSE

To evaluate the prevalence of amblyopia and associated biometric factors in Danish children.

METHODS

Determination of best-corrected visual acuity (BCVA) using ETDRS charts, non-cycloplegic subjective refractioning guided by automated refractometry, axial length and corneal curvature, fundus photography and optical coherence tomography (OCT) in 1335 children from the population-based Copenhagen Child Cohort 2000 (CCC2000) Eye Study. Birth data were obtained from the Danish Medical Birth Registry.

RESULTS

The mean (±SD) age of children was 11.7 (±0.4) years, and 47% were boys. Amblyopia prevalence was 1.5 (95% CL 0.8-2.2) %. Unilateral amblyopic eyes [BCVA < 80 ETDRS letters (0.8 snellen) and ≥2 lines difference between the eyes] was 0.6 (95% CL 0.3-1.0) mm shorter, 1.34 (95% CL 0.30-2.37) D more hyperopic and had 0.79 (95% CL 0.14-1.44) D more astigmatism compared with fellow eyes. Compared with the right eyes of the non-amblyopic children, unilateral amblyopic eyes were 1.0 (95% CL 0.5-1.6) mm shorter, 2.48 (95% CL 1.11-3.86) D more hyperopic, 1.09 (95% CL 0.43-1.75) D more astigmatic and had a 47 (95% CL 13-81) μm thicker subfoveal choroid.

CONCLUSION

Amblyopia was found in 1.5% of Danish children born 22 years after the inception of the nationwide preschool visual screening programme. Amblyopia was associated with anisometropia, astigmatism, a thicker subfoveal choroid and a history of childhood strabismus.