Cryotherapy for treatment of active retinopathy of prematurity: experience in London, Ontario.

Between January 1985 and May 1990, 49 infants (97 eyes) with stage 3 "plus" retinopathy of prematurity (ROP) were treated with cryopexy. The mean gestational age at birth was 29.6 weeks and the mean birth weight 753 g. At the time of treatment the mean chronologic age was 8.7 weeks and the mean weight 1629 g. Noncutting cryopexy was applied to the entire avascular peripheral retina, anterior to the mesenchymal ridge. Confluent treatment was done anteriorly to the posterior border of the pars plana. Favourable results, defined as a normal-appearing fundus (apart from the cryopexy scars) with no retinal folds or traction, were observed in 70% of the eyes an average of 13.8 (range 2 to 60) months after treatment. Our results emphasize the importance of early detection of ROP and diligent monitoring and treatment of affected infants.