Prevalence of retinopathy of prematurity: an institutional cross-sectional study of preterm infants in Brazil.

OBJECTIVE Retinopathy of prematurity (ROP) is the leading cause of childhood blindness in most developed countries. This study aimed to verify ROP prevalence among all very low birth weight (VLBW) preterm infants admitted to a level-3 teaching hospital in Porto Alegre, Rio Grande do Sul, Brazil. METHODS Institutional cross-sectional study of 407 premature infants with birth weight < or = 1,500 g or gestational age (GA) < or =32 weeks between 2002 and 2007. All infants screened for ROP were examined after the fourth week of life and followed up until the 45th week of adjusted GA. ROP prevalence was estimated at a 95% confidence level. RESULTS Some degree of ROP in one or both eyes occurred in 25.5% (104) of all screened infants, and severe ROP (threshold stage 3 or higher, requiring treatment to prevent vision loss, as per the criteria of the U.S.-based Multicenter Trial of Cryotherapy for Retinopathy of Prematurity, CRYO-ROP) occurred in 5.8% (24). Based on the criteria of The International Classification for Retinopathy of Prematurity (ICROP, 1984/1987), the disease reached stages 1, 2, and 3 in 11.3% (46), 8.4% (34), and 5.4% (22), respectively. One infant developed the disease up to stage 4 (partial retinal detachment), and one progressed to stage 5 (complete retinal detachment, resulting in 0.2% overall prevalence for ROP-induced blindness). CONCLUSIONS Overall incidence of ROP in this institutional study (25.5%) was comparable to international results from developed countries. A comprehensive countrywide survey on ROP in Brazil is recommended to determine any regional differences in disease prevalence.