Development of astigmatism and anisometropia in preterm children during the first 10 years of life: a population-based study.

OBJECTIVE: To assess the development of astigmatism and anisometropia to 10 years of age in preterm children, previously included in a population-based study on the incidence of retinopathy of prematurity.
METHODS: Cycloplegic retinoscopies were performed in 198 preterm children at 6 months, 2(1/2) years, and 10 years of age. We analyzed the development of astigmatism of 1 diopter (D) or more and anisometropia of 1 D or more.
RESULTS: The amount and prevalence of astigmatism declined between 6 months and 2(1/2) years of age and then remained stable. We found no difference in the course of astigmatism at different ages with regard to stage of retinopathy of prematurity. The amount of anisometropia increased, but its prevalence remained unchanged. Multiple regression analyses showed that astigmatism of 1 D or more at 2(1/2) years of age and cryotreated severe retinopathy of prematurity were risk factors for astigmatism at 10 years of age, and that anisometropia of 2 D or more at 2(1/2) years of age was a risk factor for anisometropia at 10 years of age.
CONCLUSIONS: The development of astigmatism and anisometropia showed a similar course, regardless of stage of retinopathy of prematurity. The retinoscopy findings at 6 months of age were of no value in predicting astigmatism and anisometropia at 10 years of age, but the refraction at 2(1/2) years of age was. Retinoscopy at about 2(1/2) years of age in all preterm children may be useful for detecting astigmatism and anisometropia that will persist in children of school age.