OPHTHALMOLOGICAL LONG-TERM FOLLOW-UP OF PRETERM INFANTS - A POPULATION-BASED, PROSPECTIVE-STUDY OF THE REFRACTION AND ITS DEVELOPMENT

Background-Numerous studies have reported an increased risk of refract ive errors in prematurely born infants, but only few have been long te rm and strictly population based. Methods-A 3.5 year ophthalmological long term follow up of 248 preterm infants was performed. The infants had been included in a previous epidemiological study of retinopathy o f prematurity (ROP) (birth weight less than or equal to 1500 grams). T he incidence of refractive errors and development of refraction were s tudied, based on retinoscopies at 6 and 30 months of corrected age. Re sults-The overall incidence of myopia was 8% at 6 months, of which 35% was transient, and 10% at 30 months. Of the cryotreated infants, 30-4 0% were myopic at both retinoscopies. The incidence of astigmatism was 52% at 6 months and 26% at 30 months. Astigmatism was associated with ROP, but not with cryotreated ROP itself. Astigmatism ''against the r ule'' was commoner than astigmatism ''with the rule''. Anisometropia o ccurred in 6.5% of the infants at 6 months and in 8.4% at 30 months. T he incidence of anisometropia was higher in eyes with ROP, particularl y in cryotreated eyes, which tended to have high and persistent anisom etropia. Conclusion-The risk of refractive errors is higher in preterm infants than in infants born at term, and also prematurely born infan ts without ROP do run an increased risk of having myopia and anisometr opia. We recommend follow up examinations with retinoscopy for all inf ants included in screening programmes for ROP.