Retinopathy of prematurity: incidence and treatment.

The incidence of retinopathy of prematurity in infants with a birthweight less than or equal to 2500 g admitted to a tertiary neonatal intensive care unit between 1977 and 1983 was 20% of all survivors. There was a reciprocal relation between birthweight and the incidence of the disease, with an incidence of 68% in infants weighing less than or equal to 1000 g at birth. Cryotherapy of the avascular retina was performed if the acute disease progressed rapidly during stage 3 and the amount of fibrovascular proliferation was mild to moderate with signs of plus disease (presence of appreciable posterior pole vascular tortuosity and dilatation and the presence of engorgement of iris vessels). This method of treatment was performed in 4% of all survivors: in 26% of infants weighing less than or equal to 1000 g at birth and 5% of infants weighing 1001-1500 g. No infants had cicatricial disease greater than stage 2 on follow-up. The absence of any severe cicatricial disease or blindness in this large group of high risk infants suggests that when indicated and performed on the avascular retina cryotherapy may be an important method of treatment.