Incidence and Time of Onset of Retinopathy in Premature Infants in Korea

Purpose: This study examined the incidence and time of onset of retinopathy in premature infants in Korea.Methods: The medical records of premature infants admitted to the neonatal intensive care unit from 2006 to 2018 were reviewed retrospectively. Stages 1 and 2 were classified as mild retinopathy and stages 3 and 4 were considered severe. The incidence, severity, time of diagnosis, associations between retinopathy and birth weight and also gestational age, and clinical characteristics of the treated infants were analyzed.Results: The incidence of retinopathy was 10.9% with an average time of diagnosis at 34.92 weeks postmenstrual age; the frequency of severe retinopathy was 44.97%. Birth weight and gestational age were significantly lower in premature infants with retinopathy than in normal infants. In addition, birth weight was significantly lower in those with severe retinopathy than in those with mild retinopathy. For birth weight and gestational age, the incidence and severity of retinopathy tended to be higher in those with birth weights less than 1,000 g and gestational ages of less than 27 weeks. Of the infants, 4.51% underwent laser photocoagulation; the times of diagnosis, progression to type 1 retinopathy, and treatment were 33.75, 35.06, and 36.04 weeks postmenstrual age, respectively.Conclusions: The incidence and severity of retinopathy of premature infants increased in those with birth weights less than 1,000 g and gestational ages less than 27 weeks. Such infants should be monitored carefully between 32 to 36 weeks of postmenstrual age, when retinopathy is mainly diagnosed.