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.