Visual screening of Swedish children: an ophthalmological evaluation.

This study describes the various ophthalmological conditions detected in the Swedish visual screening program for children. The study was longitudinal and retrospective. All children (3126) born in 1982 in three Swedish municipalities have been followed from birth to ten years of age. Visual acuity was examined at the ages of 4, 5.5, 7 and 10 years. Before the age of 4, a gross examination of the eyes was performed. The prevalence of ametropia in the population was 7.7%, the prevalence of strabismus 3.1%, and the prevalence of organic lesions 0.6%. Seven children (0.2%) were visually handicapped (visual acuity </=0.3 in the better eye). Refractive errors and microtropias were mainly detected at the age of 4, when the first visual acuity test was performed, while manifest strabismus was in many cases detected before this age. With this screening and subsequent diagnosis and treatment, the prevalence of deep amblyopia (visual acuity </=0.3) has been reduced from 2% to 0.2%. With treatment, 47% of the amblyopic children achieved a visual acuity better than 0.7. Visual screening is effective in detecting visual and ocular disorders. Most conditions are discovered before the age of 6. Compared to an unscreened population, the prevalence of amblyopia is greatly reduced.