Abstract
Abstract: :
Purpose: To examine the prevalence of visual deficits in acuity and binocularity in a population of 7-8 year old children in a defined geographical area, in relation to an earlier infant screening programme. Children tested in years two and three were in the age cohort that had been offered video-refractive screening (Anker et al ARVO 1995), while the majority of children tested in the first year of the project were out of this cohort. Methods: All primary schools in the Cambridge Health District were invited to participate in this study, and 72 schools participated. Identities of the 5916 7-8 year-old children tested were checked against records of the infant screening. 2297 children had received infant video-refractive screening; 3619 children had not. Children were tested with the Cambridge Crowded Cards (equivalent to Snellen) at 3 metres viewing distance, and a near version used at 30 cm. Visual acuity in each eye was recorded, with and without spectacle correction (if worn), and stereo vision was assessed using the Lang test. Results: Criteria for a vision problem were any of the following: a distance acuity in either eye lower than 6/9 (20/30), near acuity in either eye lower than 6/12 equivalent (20/40) or a two line difference between the eyes at either near or far. The prevalence of acuity problems detected was significantly lower in the children screened in infancy (5.6%), compared to those who had not been screened (7.3%) (chi square p<0.01). The group screened in infancy were also significantly more likely to pass the Lang stereo test (at least 2/3 targets detected) than those never screened (97.3% vs 96.3%; chi square p<0.05). Conclusion:The results suggest that refractive screening in early infancy has a significant beneficial effect on visual outcome at age 7+ years. Early refractive correction or other treatment resulting from infant screening, and better awareness by parents of the need for regular eye checks, are possible factors.
Keywords: 623 visual development: infancy and childhood • 575 screening for ambylopia and strabismus • 620 visual acuity