incidence and risk factors of retinopathy of prematurity

purpose: to determine the incidence of retinopathy of prematurity (rop) and to evaluate the possible neonatal risk factors for rop among premature infants referred to farabi eye hospital during 2000-2002. methods: newborn infants with gestational age (ga) £ 37 wk or birth weight (bw) £ 2500 g were included. the first eye examination was performed 4-9 weeks after birth. data on possible risk factors include low birth weight, low gestational age, sepsis, supplemental oxygen therapy, blood transfusion, phototherapy, multiple pregnancy, and respiratory distress syndrome (rds) were compared between the two groups of newborns with and without  rop. univariate and multivariate analysis was performed. results: one hundred eighty five neonates were included in this study (110 male, 75 female). mean ga ± sd was 31.64 ± 2.67 wk and mean bw ± sd was 1620.68 ± 467.6 g. the incidence of rop was 12.4% (95%ci: 7.6%-17.2%) including 8.6% in threshold and 3.8% in prethreshold stages. rop was present in 18.6% of neonates with ga < 32 wk and 29% of neonates with ga < 28 weeks. all rop cases had ga £ 33 wk. mean ga ± sd was 29.39 ± 2.16 wk in the rop group and 31.96 ± 2.58 wk in the non-rop group. (p< 0.001) mean bw ± sd was 1283.48 ± 342.84 g in the rop group and 1668.55 ± 464.04 g in the non-rop group. (p< 0.001) rop was pesent in 20.5% of neonates with bw £ 1500 g. all rop cases had bw £ 2000 g. there was a significant association between blood transfusion and incidence of rop (odds ratio= 3.75, p= 0.004), rds (or= 3.14, p= 0.041), and phothotherapy (or= 2.86, p= 0.044) based on univariate analysis. there was no significant association between oxygen therapy and incidence of rop. based on multivariate logistic regression analysis, low ga was the only significant factor associated with high incidence of rop. coclusion: we suggest ga ≤ 33 wk and  bw < 2000 g as the best criteria for screening of high risk neonates for developing  rop. these  criteria deserve further investigation.