Preschool vision screening: a prospective comparative evaluation.

We have reviewed the results of a pilot study of preschool screening by orthoptists for vision defects which was introduced in Newcastle in 1987. We have compared the visual outcomes, at age 7 years, of children who were screened at age 3 years by either orthoptists, health visitors or general practitioners in three matched, geographically defined cohorts. Manifest, large angle strabismus presented at the same age, and in roughly equal numbers in each cohort. Orthoptic screening detected many more cases of amblyopia associated with microtropia and anisometropia, but the b overall amblyopia prevalence at age 7 years was similar in each cohort. This study does not provide evidence to support the nationwide introduction of primary orthoptic preschool vision screening, and highlights the need for a prospective treatment trial of amblyopia associated with microtropia and anisometropia.