Multicenter Trial of Cryotherapy for Retinopathy of Prematurity

The multicenter trial of cryotherapy for retinopathy of prematurity (ROP), whose preliminary results are reported in this issue of theArchives,¹was designed to resolve the uncertainty about the value of treatment and to evaluate its drawbacks and possible benefits. Preliminary results weigh heavily in favor of treatment, and thus constitute an important contribution to the management of ROP, a disorder with the potential to blind many hundreds of premature infants each year.² See also pp 457 and 471. By comparing paired sample data from infants with symmetric disease and independent sample data from infants with asymmetric disease in 172 premature infants at 23 centers, the study confirmed that cryotherapy conferred a clear benefit at three months after treatment. The benefit represents an approximate 50% reduction in unfavorable events defined as the presence of a retinal fold, retinal detachment, or retrolental tissue (21.8% of the treated eyes vs