Results of vision screening of 6-year-olds at school:: a population-based study with emphasis on screening limits

Purpose: To evaluate newly introduced vision screening of 6-year-olds in the preschool class with special regard to screening criteria. Methods: Monocular visual acuity (VA) testing in 6-year-olds by school nurses as part of preventive health care was introduced in Sweden 2003. Children with VA < 0.8 (logMAR 0.1) or symptoms are referred to eye clinics where VA testing, cover testing, cycloplegic autorefraction and ophthalmoscopy are performed. The present screening limit of 0.8 (logMAR 0.1) was evaluated in relation to a limit of 0.65 (logMAR 0.2). All children in the City of Gothenburg starting preschool class in 2003 were included. Results: A total of 127 schools with 3885 pupils participated. Of these, 255 pupils (6.6%) were referred and 236 underwent an ophthalmological examination. Children with a VA of 0.65 (logMAR 0.2) in the worse eye constituted 74.5% of those who had failed the screening; more than half of these were found to have VA >= 0.8 (logMAR 0.1) in the clinic. Many were not refracted in cycloplegia and only 6.7% were found to have significant ametropia. The criteria for the prescription of glasses varied; 13.4% of these children were prescribed glasses for insignificant refractive errors. Conclusions: Six-year-olds with VA of 0.65 (logMAR 0.2) rarely have defects that require treatment and the screening criterion of 0.8 (logMAR 0.1) is probably too demanding for effective utilization of available resources. Retest before referral and refraction in cycloplegia of all children with reduced VA or visual symptoms are recommended.