The Impact of Modest Prematurity on Visual Function at Age 6 Years

To determine the effects of modest low birth weight and prematurity on visual function of children predominantly aged 6 years.Children with a birth weight of 1500 to 2499 g were considered exposed to a modest low birth weight (n = 82) and were compared with children with a birth weight of 2500 g or more (n = 1386). Exposure to modest prematurity, 32 to 36 weeks' gestation (n = 115), was similarly analyzed and compared with birth at term, 37 or more weeks' gestation (n = 1446). Logarithm of the minimum angle of resolution visual acuity was measured in both eyes. Cycloplegic autorefraction (cyclopentolate), cover testing, and dilated fundus examinations were performed.A modest low birth weight increased the risk of amblyopia (relative risk [RR], 5.1; 95% confidence interval [CI], 2.2-12.0), strabismus (RR, 3.7; 95% CI, 1.5-9.1), and anisometropia (RR, 3.7; 95% CI, 1.2-11.1), together with an increased risk of uncorrected visual acuity in the lowest quartile (RR, 1.7; 95% CI, 1.3-2.2). Modest prematurity increased the risk of amblyopia (RR, 4.5; 95% CI, 1.9-10.6), strabismus (RR, 2.6; 95% CI, 1.1-6.0), and uncorrected visual acuity in the lowest quartile (RR, 1.5; 95% CI, 1.1-2.0).Modest degrees of low birth weight and prematurity may be associated with increased ophthalmic morbidity at age 6 years.