Visual function in 6 to 7 year-old children born extremely preterm: a population-based study.

PURPOSE

Progress in neonatal care has caused an increased survival of children born extremely preterm. The aims of this study were to examine the long-term visual function and ocular development in an unselected cohort of extremely preterm infants and relate the results to neonatal morbidity and long-term neurodevelopmental outcome.

METHODS

All children with gestational age of 22-27 completed weeks or birth weight of 500-999 g born in the years 1999-2000 in two counties of Western Norway (n = 52) were invited to an eye examination that included visual acuity, refractive error, binocular function, accommodative amplitude and fundus examination. Cognitive function was assessed with the WPSSI-R test and motor abilities with the ABC movement test.

RESULTS

Neonatal morbidities and neurodevelopmental outcome were known for all, while 37 of the 52 children underwent the eye examination. None were blind or visually impaired, but 46% had subnormal visual acuity (logMAR ≥0.1). Ninety per cent were emmetropic or slightly hypermetropic (0 to +3D), while 10% had manifest and 51% latent strabismus. Performance IQ on the WPSSI-R test and ABC total score were associated with best visual acuity (p = 0.03 and p < 0.01, respectively). In a multiple linear regression model, visual acuity in the best eye was significantly associated with performance IQ (p = 0.03) and ABC total score (p = 0.02).

CONCLUSION

This study suggests a more favourable long-term prognosis on important ocular and visual parameters in survivors of extreme prematurity than expected from similar reports on children born less prematurely and that performance IQ and motor function are related to visual acuity.