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.