Frequency and natural history of retinopathy of prematurity (ROP). A prospective study in a Swedish city 1986-1990.

Frequency and natural history of retinopathy of prematurity (ROP) were prospectively studied in 142 preterm infants with birth weight (BW) less than 1501 g and/or gestational age (GA) below 33 weeks, who were born in Malmö 1986-1990. ROP developed in 27 (19%) of the 142 infants. The frequency of the ROP was significantly higher in infants with BW < or = 1000 g (54%) and in those with GA < or = 28 weeks (40%) than above these values. Infants with ROP had, compared with those without ROP, significantly lower BW, lower GA, lower Apgar score at 1 and 5 min, longer period of oxygen-therapy and higher frequency of neonatal complications. Five infants with stage 3 ROP were treated with cryotherapy; four with moderate changes showed good regression, the fifth with a severe stage 3 progressed and became blind. Up to 5 years follow-up revealed a significantly higher frequency of strabismus (40% vs 8%), myopia (25% vs 4%), and amblyopia (33% vs 6%) in infants with ROP than in those without ROP. Astigmatism and anisometropia were also frequent in children with ROP.