The prevalence of retinopathy of prematurity in very low birth weight newborn infants.

OBJECTIVE

To evaluate the prevalence of retinopathy of prematurity and the risk factors affecting very low birth weight infants at a neonatal intensive care unit.

METHODS

A cross-sectional study investigating all newborn infants with birth weights < or = 1,500 g and/or gestational ages < or = 32 weeks, admitted to the Neonatal ICU at the Hospital de Clínicas de Porto Alegre, from October 2002 to March 2004. Patients underwent indirect binocular ophthalmoscopy of the fundus at six weeks postpartum. Infants who progressed to threshold disease were given laser therapy.

RESULTS

One hundred and fourteen newborn infants were studied. Eighty-three patients were not diagnosed with retinopathy of prematurity, 18 had stage I retinopathy of prematurity, seven stage II retinopathy of prematurity and six patients had threshold retinopathy of prematurity. The prevalence of retinopathy of prematurity was 27.2% (95% CI: 19.28-36.32) affecting 31 newborn infants, and the prevalence of retinopathy of prematurity progressing to threshold disease was 5.26% (95% CI: 1.96-11.10), affecting six patients. Retinopathy of prematurity was confirmed in 50% of the patients with weights below 1,000 g and 71.5% of newborn infants born at gestational ages of less than 28 weeks. Gestational age and birth weight were significantly lower among patients with retinopathy of prematurity than among those without.

CONCLUSIONS

Although the results of this study demonstrate that the observed prevalence was similar to that described in literature, this ROP frequency remains elevated among very low birth weight infants. The development of retinopathy of prematurity was inversely proportional to weight and gestational age at birth.