Screening for visual and ocular disorders in children, evaluation of the system in Sweden

The aim of this study was to evaluate the visual screening system in Sweden. We have made a retrospective investigation of the results of screening for ocular disease and visual impairment of all children born in 1982 in three Swedish communities. The records from screening examinations from 0 to 10 y and from diagnostic follow-up at the departments of ophthalmology that the children were referred to were inspected. The data were used to evaluate the efficiency of the Swedish visual screening system. The study included 3126 children. The attendance rate at the 4-y examination was better than 99%. The sensitivity of the 4- and 5.5-y screening examinations was on the average 92% and the specificity was 97%. The average number of false negative cases at 4 y was 5.6 in 1000 (0.56%). With this screening and subsequent diagnosis and treatment, the prevalence of amblyopia at different levels of visual acuity at the age of 10 y was: 0.06% with visual acuity < or = 0.1, 0.9% with visual acuity < or = 0.5 and 1.7% with visual acuity < or = 0.7. In spite of largely unchanged pressure of amblyogenic factors in the population, the prevalence of deep and moderate amblyopia has been markedly reduced by screening and early treatment.