Survival and characteristics of retinopathy of prematurity in micro-premature infants.

Objective: To describe the risk and nature of retinopathy of prematurity (ROP) in micro-premature infants (≤26 weeks' gestational age [GA]).

Methods: Retrospective analysis of prospectively collected data from infants born at 22-26 weeks' GA over a 5-year period.

Results: A total of 502 infants were identified, of whom 414 survived to discharge (82.5%). The Vermont Oxford Network database documented clinical follow-up data and ROP outcomes for all 414 patients; complete ROP clinical records were available for 294 of the infants who survived (70.8%). Forty infants were born between 22 and 23 weeks' GA (group A, 13.6%), and 254 were born between 24 and 26 weeks' GA (group B, 86.4%). Survival for group A infants was worse than that of group B infants (66.2% vs 85.4%; p < 0.01). Survival of group A infants improved during the study period (R = 0.625). Overall, 59.9% of infants developed any ROP and 8.5% developed type 1 ROP. Group A infants were more likely to develop ROP (90.0% vs 48.6%; p < 0.01) and type 1 ROP (30.0% vs 5.1%; p < 0.01) than group B infants. Group A infants developed ROP at an earlier age (32 + 6 weeks vs 33 + 3 weeks; p = 0.02) and were more likely to have zone I disease on presentation (65.0% vs 20.5%; p < 0.01), but there was no difference in the corrected gestational age of peak severity of ROP (35 + 2 weeks vs 34 + 5 weeks; p = 0.36).

Conclusion: The most premature infants, born at 22-23 weeks' GA, develop ROP at an earlier age, are more likely to present with posterior disease, and have a high risk of disease requiring treatment.