By Megan Rauscher
New York - A new study confirms that children born prematurely (before 35 weeks gestation) run a higher risk of developing vision problems than children born at term.
This is true regardless of the degree to which blood vessels in the retina have developed abnormally because of preterm birth - a condition known as "retinopathy of prematurity."
The new study, reported in the Archives of Ophthalmology, also suggests that eye tests performed at 2,5 years of age in preterm children can predict vision problems at age 10 - namely, astigmatism, which is an unequal curve in of the eye's refractive surfaces, and anisometropia, a difference in refractive power between the two eyes that can lead to partial vision loss.
In a previous study, the investigators showed that refractive errors are about four times more common in preterm children compared to full-term children, at the age of 10 years.
In the current study, Dr Eva Larsson of Uppsala University Hospital, Sweden and colleagues analysed the development of astigmatism and anisometropia in the preterm group (198 children) at 6 months, 2,5 years and 10 years of age.
The prevalence and degree of astigmatism declined between 6 months and 2,5 years of age and then remained stable, the team reports. A total of 108 children had astigmatism at six months, 54 at 2,5 years and 41 at 10 years.
The degree of anisometropia did not change between six months and 2,5 years but increased between 2,5 and 10 years of age. The prevalence of anisometropia, however, remained fairly stable, affecting 15 children at 6 months, 17 at age 2,5 years, and 16 at age 10.
"The presence of astigmatism and anisometropia at 2,5 years of age were the strongest risk factors for having astigmatism and anisometropia at 10 years of age," the authors write.
"Although the children with severe cryotreated retinopathy of prematurity had the highest prevalence of refractive errors, we found that the development over time of astigmatism and anisometropia... was similar, regardless the stage of retinopathy of prematurity," Larsson told Reuters Health.
All preterm children need follow up eye examinations, Larsson and colleagues conclude, irrespective of the degree of retinopathy of prematurity at birth.
SOURCE: Archives of Ophthalmology November 2006.