Cryotherapy for retinopathy of prematurity: timing of intervention.

This is a retrospective study of the results of cryotherapy for retinopathy of prematurity in 30 eyes of 17 patients from November 1976 to March 1983. The report is in the language of the international classification of retinopathy of prematurity. Ten eyes were treated at stage 4 disease, seven eyes at severe or late stage 3 'plus' disease, and 13 eyes at moderate or mid-stage 3 'plus' disease. All eyes had the cryotherapy applied to the ridge and the extraretinal fibrovascular proliferation contiguous with the ridge, some with additional treatment of the avascular retina. The results show that this method of treatment must be applied before severe stage 3 'plus' disease is established in order to prevent visual disability and minimise retrolental fibroplasia. The treatment of the selected cases of progressive moderate stage 3 'plus' disease accomplished those objectives.