Retrolental fibroplasia: a new analysis of risk factors based on recent cases.

Over an 18-month period, four severe and eight mild cases of retrolental fibroplasia (RLF) were diagnosed. All infants had gestational age less than 34 weeks. While the percentage of infants with RLF increased with decreasing gestational age, the severity of RLF was not related to birth weight or gestational age. These RLF infants were compared with premature infants having normal fundi. The arterial blood gas values in the first week of life were similar for the two groups. However, during the subsequent weeks of oxygen therapy, the infants who developed severe RLF had a significantly greater number of hours of capillary oxygen tension at undesirable levels (Pcap O2 greater than 50 mm Hg) than the mild RLF or control infants. These results suggest that infants may be at greatest risk of severe retinal damage from oxygen relatively late in the course of their oxygen therapy.