Abstract
Abstract: :
Purpose:To assess the impact of hyperopia and/or astigmatism and the effects of spectacle correction on the learning potential of low income preschoolers. The hypotheses were: 1) children with hyperopia and/or astigmatism would score lower than age–matched emmetropic controls on standardized tests of cognitive and motor development; 2) the ametropic group would score at the same level as controls after correction. Methods: The study sample consisted of 61 children (mean age = 4½ years; 57% female; 87% Latino), 33 children had bilateral hyperopia/astigmatism and no other significant ocular problem, and 28 age–matched control children were emmetropic. Eligible subjects were enrolled from Head Start centers and public preschools serving low–income families. For this study, hyperopia and/or astigmatism were defined as cyclopegic refraction ≥ 4 diopters for hyperopia in 3 to 5 year–olds and for astigmatism ≥ 2 diopters in 3 year–olds and ≥1.50 D in 4 and 5 year–olds. Children were assessed at baseline before receiving glasses and again after wearing glasses for 6 weeks using age–normed standardized measures of cognitive and visual–motor abilities. Main Outcome Measures: The primary outcome measure was the Wechsler Preschool and Primary Measure of Intelligence–Revised (WPPSI–R). Secondary outcome measure was the Developmental Test of Visual–Motor Integration (VMI). Results: No differences were found in demographic and socio–economic characteristics between the target and control groups. Two–sample t–tests revealed that children with hyperopia/astigmatism had significantly lower scores than the control group on the Performance subscale of the WPPSI–R (p = .013) and on the VMI (p = .009). Subgroup analyses across the refractive conditions using a General Linear Model revealed that children with hyperopia and with a combination of hyperopia and astigmatism had significantly worse outcomes compared to controls (WPPSI–R Full Scale, p = .021, Performance, p = .006, and VMI, p = .003). These differences were not explained by differences in verbal abilities, p = .72. After wearing corrective lenses for 6 weeks, an ANCOVA adjusted with baseline scores revealed that these differences were no longer significant, p ≥ .29. Conclusions: Findings showed that hyperopia/astigmatism was associated with a significant disadvantage in the cognitive and visual motor abilities of low income preschoolers and suggested that wearing corrective lenses for 6 weeks was effective in overcoming its negative impact.
Keywords: refractive error development • visual development: infancy and childhood • perception