Threshold retinopathy of prematurity in neonates less than 25 weeks' estimated gestational age

Introduction: The survival rate of extremely premature infants has increase d. No recent study has investigated the characteristics of retinopathy of p rematurity (ROP) or the incidence of threshold ROP in the most severely pre mature infants, We undertook this study to determine the risk of developing ROP and threshold ROP in the growing subpopulation of infants <25 weeks' e stimated gestational age (EGA). Methods: A retrospective review of infants born before the 25th week of gestation between the years 1994 and 1997 was performed. Of 49 infants examined (97 eyes), 42 were born in the 24th week of gestation and 7 were born in the 23rd week. Mean follow-up was 6.3 month s (range, 2.5-37 months). Ophthalmology screening examinations were initiat ed at 5 weeks of age and continued until the infants were no longer at risk for serious ROP. Results: ROP developed in all (97) eyes. Thirty-nine of 9 7 (40%) eyes in 20 of 49 (41%) infants developed threshold ROP, diagnosed a t a mean postconceptional age of 34 weeks. Thirteen (13%) eyes of 7 (14%) p atients developed prethreshold disease and regressed without treatment. Con clusion: There is an increased incidence of threshold disease in infants le ss than or equal to 25 weeks' EGA compared with children of greater EGA. Th reshold disease may occur at an earlier postconceptional age in this subgro up of neonates.