Ophthalmological aspects of prematurity

Abstract: In a prospective, population-based study of a weIl defined geographical area in Sweden, an ROP incidence of 40.4% was found among 260 prematurely born infants with a birth weight of 1500 grams or less. Cryotherapy was performed in 10.8% of the infants. Gestational age at birth and birth weight were significantly associated with ROP. A 3.5-year ophthalmological foIlow-up of the 260 prematurely bom infants was performed. In the refraction there was a reduction in the mean spherical equivalents with increasing degrees of ROP. Myopia (examination at 2 1/2 years) was commonest in eyes with ROP (18% of light eyesl 15% of left eyes), particularly in those treated with cryo (40%/27%). Astigmatism was associated with ROP, but not with cryotherapy per se. Astigmatism was also associated with low birth weight. Marked anisometropia was related to cryotreated ROP. A visual handicap (visual acuity <0.3) was found in 2.5% of the children and severe visual impairment (visual acuity <0.1) was present in two children (0.8%), of whom one was blind. Neurological complications and the degree of ROP, including cryotreated ROP, were significant risk factors for poor vision. Strabismus, seen in 13.5% of the total study population, was significantly associated with neurologicallesions and their sequelae, anisometropia and cryotreated ROP. Prematurely bom infants without ROP ran an increased risk of myopia, anisometropia and strabismus as compared to a nOlmal population, which emphasizes the need for ophthalmological follow-up of pre term infants even with out ROP. In a selected group of children with pretelm cerebral lesions, visual impailment was commoner in children with ischaemic lesions (leucomalacia and infarcts) than in children with haemonhagic lesions. Pathological"crowding" in visual acuity assessment was also most commonly seen in ischaemic lesions, which implied an overestirnate of vision by tests with solid objects and single optotypes in relation to linear optotype acuity. Difficulties in interpreting complex pietures were found in the whole study group. In a retrospective study of the mothers of infants from the population-based study, essentiai hypertension before pregnancy was the only maternallisk factor associated with ROP in a logistic, multiple regression analysis. Among risk factors for pretelm birth in our population, socioeconomic factors (mmital status and education), as well as smoking, played a less prominent roI e than in previous studies. In a retrospective study of neonatal Ii sk factors in the same population, gestational age at birth, bronchopulmonary dysplasia, and low birth weight were significantly associated with ROP. In both studies, prematmity per se remained the strongest risk factor for ROP. Screening for ROP in our area is recommended for infants with a gestational age at birth of 32 weeks or less, and long-telm opthalmological follow-up is suggested for all of them, with particular emphasis on those infants that run the highest risk of complications - i.e., those who have had cryotherapy and/or have neurological complications.