Written on Thursday, January 04, 2007 by Gemini
Testing the eyes of pre-term children when they reach 2.5 years of age may predict vision problems at age 10, according to a report in the November issue of Archives of Ophthalmology. “Ophthalmological studies of pre-term (prematurely born) children have resulted in recommendations that they need follow-up examinations, to find those in need of extra help,” the authors provide as background information in the article.
“However, such follow-up programs are expensive and must be based on accurate knowledge of the prevalences of ophthalmological disorders in pre-term and full-term children.” Previous studies have found that refractive errors, or errors in the degree of light that reaches the back of the eye, are more common in pre-term children (born before 35 weeks gestation) than full-term children.
Eva Larsson and colleagues at Uppsala University Hospital, Sweden, performed retinoscopies—tests for refractive errors that involve examining the back of the eye—in 198 pre-term children at 6 months, 2.5 years and 10 years of age. The investigators assessed the development of astigmatism, an unequal curve in one of the eye’s refractive surfaces, and anisometropia, a difference in refractive power between the two eyes that can lead to partial vision loss.s.
The prevalence and degree of astigmatism declined between 6 months and 2.5 years and then remained stable through 10 years; 108 children had astigmatism at six months, 54 at 2.5 years and 41 at 10 years. The amount of anisometropia in the entire group showed no change between six months and 2.5 years of age but increased between 2.5 and 10 years.
The prevalence, however, remained stable: 15 children had anisometropia at 6 months, 17 at age 2.5 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. “In this population-based study, we found that a refractive error at 2.5 years of age predicts that refractive error will also be present at 10 years of age,” they conclude.
Recommendations for follow-up examinations must include all aspects of visual function—acuity, contrast sensitivity and visual fields, as well as the refraction, strabismus and perceptual problems. All pre-term children should be included in such follow-up examinations for refractive error, irrespective of the retinopathy of prematurity stage,” or the degree to which blood vessels in the retina have developed abnormally because of pre-term birth.