Purpose: To compare emergent literacy skills in uncorrected hyperopic and emmetropic children.
Methods: "Hyperopes" (>or=2.00 D sphere along the most hyperopic meridian; n=13; aged 67+/-13 mo) and "emmetropes" (<or=1.50 D sphere along the most hyperopic meridian; n=19; aged 58+/-12 mo) were tested for visual acuity (VA) and assessed for their emergent literacy skills [three standard tests (letter/word reading skills, receptive vocabulary and phonological awareness) and an experimental test of emergent orthography]. Parents completed a survey of family demographics, health/developmental concerns and home literacy experiences. Visual motor and visual perceptual skills tests were used to assess any visual cognitive differences.
Results: There were no differences in single letter VA for hyperopes and emmetropes and crowded letters for the right eye. Crowding effects were significantly greater in the left eye for hyperopes (t (30)=-2.74, p=0.01), with two of the hyperopes showing abnormal crowding. Hyperopes lagged behind emmetropes in letter and word recognition ability (Mann-Whitney U=72, p=0.049), receptive vocabulary (F(1,30)=9.64, p=0.004), and emergent orthography (F(1,29)=5.43, p=0.03). The groups did not differ in phonological awareness skills (F(1,29)=0.39, p=0.54). No statistically significant differences between the two groups were found for visual motor or visual perceptual skills, age, and some family variables known to contribute to emergent literacy skills.
Conclusions: In this pilot study, uncorrected hyperopic children, ages 4 to 7 years, show reduced performance on tests of letter and word recognition, receptive vocabulary, and emergent orthography and crowded VA, despite no difference in phonological awareness skills, visual cognitive skills, and other family variables known to affect the acquisition of literacy skills. The relationship between hyperopia and the poorer progress in emergent literacy is complex, and it is not clear if the relationship is causal, and whether the hyperopes will catch up to the emmetropes with time.