Preterm children at greater risk of astigmatism

Children born before week 35 of pregnancy have a greater risk of developing refractive errors than children born at full term, according to a report published in the November 2006 issue of Archives of Ophthalmology.

Eva Larsson, MD from Uppsala University Hospital, Sweden, conducted a study to investigate the development of astigmatism and anisometropia of 1 diopter (D) or more in 198 preterm children at six months, 2.5 and 10 years of age.

The amount and prevalence of astigmatism declined between six months and 2.5 years of age and stabilised. A total of 108 children had astigmatism at six months, 54 at 2.5 years and 41 at 10 years. No difference was found in the course of astigmatism at different ages in relation to the stage of retinopathy or prematurity. Anisometropia did increase but its prevalence was unchanged.

Using multiple regression analyses, the researchers found that astigmatism of 1 D or more at 2.5 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 2.5 years of age was a risk factor for anisometropia at 10 years of age.

Dr Larsson noted that the development of astigmatism and anisometropia show a similar course, regardless of the stage of retinopathy of prematurity and that refraction measurements at 2.5 years of age can be used as a predictor of later refractive errors.