Incidence and Risk Factors of Retinopathy of Prematurity in Extremely Low Birth Weight and Very Low Birth Weight Infants

ABSTRACT

PURPOSE: To evaluate the risk factors and prevalence of retinopathy of prematurity (ROP) in extremely low birth weight (ELBW) infants and very low birth weight (VLBW) infants. METHODS: All babies were screened for ROP at a postconceptional age of 31 weeks or at 4 weeks of chronological age. We divided the infants into two groups according to birth weight < 1000 g (ELBW) and 1000~1500 g (VLBW), to compare the incidence of ROP and photocoagulation, and to retrospectively evaluate the risk factors. RESULTS: Three hundred eight consecutive infants were included in the data analysis. The incidences of ROP were 70.5% (79/112) in ELBW infants and 36.7% (72/196) in VLBW infants (p<0.0001). 31 of 79 ELBW infants (39.2%) and 17 of 72 VLBW infants (23.6%) had undergone photocoagulation (p<0.0001). Among the various risk factors, mechanical ventilation (p=0.039) and surfactant (p<0.000) were the independent risk factors associated with ROP in all infant groups by logistic regression analysis. In the ELBW group, however, surfactant injection was the only factor independently associated with ROP (p=0.008). The use of surfactant, the only risk factor in ELBW infants, was attributed with the initiation of ROP. However, it did not act as an aggravating factor. CONCLUSIONS: ELBW was associated with a higher incidence of ROP and laser photocoagulation. The results of this study emphasize that more special attention is needed for immature infants when ventilators and surfactants are used.