The effectiveness of preschool vision screening by health visitors.

The aim of this study was to determine the effectiveness of preschool vision surveillance by health visitors in Warrington, a district with a secondary community orthoptic service. Of the 2041 children screened by health visitors at 3-3 1/2 years 12% were referred to the orthoptist for further assessment. Sixty-three per cent of these required more than one examination by the orthoptist and 28% were subsequently referred to an ophthalmologist for further assessment. Amblyopia was detected in 11 children, 5 had squints without amblyopia, and in addition 25 children had significant refractive errors. A retrospective review of the records of children identified with amblyopia following a school entry medical at 5 years was undertaken to detect possible failure of the earlier health visitor examination (i.e. false negatives at age 3-3 1/2 years). Possible failure of early screening was found in only two children, one of whom had a minor defect only (6/9). Vision screening for children aged 3-3 1/2 years by health visitors is an effective alternative to primary screening by orthoptists. However, the use of health visitors in this role is contrary to current national guidelines. The findings suggest that using health visitors to screen vision in preschool children makes efficient use of existing routine checks and may be the best use of orthoptic time.