Uncorrected Hyperopia and Preschool Early Literacy: Results of the Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study

Purpose: To compare early literacy of 4- and 5-year-old uncorrected hyperopic children with that of emmetropic children.

Design: Cross-sectional.

Participants: Children attending preschool or kindergarten who had not previously worn refractive correction.

Methods: Cycloplegic refraction was used to identify hyperopia (≥3.0 to ≤6.0 diopters [D] in most hyperopic meridian of at least 1 eye, astigmatism ≤1.5 D, anisometropia ≤1.0 D) or emmetropia (hyperopia ≤1.0 D; astigmatism, anisometropia, and myopia <1.0 D). Threshold visual acuity (VA) and cover testing ruled out amblyopia or strabismus. Accommodative response, binocular near VA, and near stereoacuity were measured.

Main outcome measures: Trained examiners administered the Test of Preschool Early Literacy (TOPEL), composed of Print Knowledge, Definitional Vocabulary, and Phonological Awareness subtests.

Results: A total of 492 children (244 hyperopes and 248 emmetropes) participated (mean age, 58 months; mean ± standard deviation of the most hyperopic meridian, +3.78±0.81 D in hyperopes and +0.51±0.48 D in emmetropes). After adjustment for age, race/ethnicity, and parent/caregiver's education, the mean difference between hyperopes and emmetropes was -4.3 (P = 0.01) for TOPEL overall, -2.4 (P = 0.007) for Print Knowledge, -1.6 (P = 0.07) for Definitional Vocabulary, and -0.3 (P = 0.39) for Phonological Awareness. Greater deficits in TOPEL scores were observed in hyperopic children with ≥4.0 D than in emmetropes (-6.8, P = 0.01 for total score; -4.0, P = 0.003 for Print Knowledge). The largest deficits in TOPEL scores were observed in hyperopic children with binocular near VA of 20/40 or worse (-8.5, P = 0.002 for total score; -4.5, P = 0.001 for Print Knowledge; -3.1, P = 0.04 for Definitional Vocabulary) or near stereoacuity of 240 seconds of arc or worse (-8.6, P < 0.001 for total score; -5.3, P < 0.001 for Print Knowledge) compared with emmetropic children.

Conclusions: Uncorrected hyperopia ≥4.0 D or hyperopia ≥3.0 to ≤6.0 D associated with reduced binocular near VA (20/40 or worse) or reduced near stereoacuity (240 seconds of arc or worse) in 4- and 5-year-old children enrolled in preschool or kindergarten is associated with significantly worse performance on a test of early literacy.