Refractive errors in low-income preschoolers.

Purpose: To estimate the overall prevalence of refractive errors in a study population of low-income preschoolers in San Diego County. Methods: The study sample included 507 preschool children selected from a study population of all 3-5 year-old children in Head Start and San Diego Unified School District preschools (74% Latino). The sample was examined by optometrists in the mobile clinic of the University of California, San Diego, Department of Ophthalmology with retinoscopy under cycloplegia to assess the presence of refractive errors defined as myopia >= 2D in 3-4 year- olds and >= 1D in > 4 year- olds; hyperopia >= 4D in 3-4 year-olds and >= 3D in > 4 year-olds; and astigmatism >= 1.75D in 3-4 year- olds and >= 1.5D in > 4 year- olds. Anisometropia was defined as >= 1.25D difference between the eyes. Emmetropia was defined as refractive errors below these levels. Results: A total of 16% (n= 81 children) (95% confidence interval: 15.4-16.5) met study definitions of refractive errors in at least one eye. Myopia was found in 3%, ( OD Mean Sphere=2.4D); hyperopia in 7.5% ( OD Mean Sphere=3.8D); astigmatism in 5.5% ( OD Mean Cylinder=2.3D); and 84% were emmetropic ( OD Mean Sphere=1.3D). Conclusions: Hyperopia and astigmatism were the most frequent refractive errors in this sample of low-income preschoolers, most of whom were Latino.