Incidence and Risk Factors of Retinopathy of Prematurity in Mashhad, Northeast Iran

Background: Retinopathy of prematurity (ROP) is a vascular retinal disease that can cause low vision or blindness and affects premature newborns of very low birth weight. Objectives: The purpose of this study was to determine the incidence and risk factors for ROP among very premature infants in Mashhad located northeast of Iran. Material and Methods: In this cross-sectional study performed between 2006 and 2010, predisposing factors and severity of ROP were evaluated in very premature infants (<32 gestational weeks). Consecutive infants were enrolled at birth and screened for ROP at 4 to 6 weeks of age by indirect ophthalmoscopy. Severe ROP was defined as stage 4 or 5. Chi-square, Student’s t-, and Fisher’s test were used for statistical analysis. Results: The incidence of ROP was 26.2%. Significant differences between the ROP and control groups were observed, these include; gestational age, sex, birth weight, Apgar score, durationof parenteral nutrition, oxygen therapy, phototherapy, maximum PaO2 and minimum SpO2 (P < 0.05). Severe ROP was seen in 31.4% (11/32) of ROP cases (5.4% of newborns). Conclusion: The incidence of ROP is relatively high in this region. Risk factors for ROP among very premature infants include hypoxia, severe hyperoxia, relatively low blood SPO2, gestational age, birth weight, and Apgar score.