Multicenter Trial of Cryotherapy for Retinopathy of Prematurity - Ophthalmological outcomes at 10 years

Objective: To evaluate outcomes at 10 years after randomization for eyes un dergoing cryotherapy vs eyes serving as controls, for patients enrolled in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-R O). Methods: The randomized cohort originally consisted of 291 preterm children with birth weights less than 1251 g who developed a defined threshold of R OP severity in one or both eyes. Patients with bilateral threshold ROP (n=2 40) were randomly assigned to receive cryotherapy to one eye and no cryothe rapy to the other eye. Those with ROP of less severity than threshold in th e fellow eye ("asymmetric"; n=51) were randomly assigned to cryotherapy or no cryotherapy in the eye with threshold ROP. Ten years later, a tester who was masked to treatment status of each eye measured distance and near visu al acuity, with "unfavorable" outcome being 20/200 or worse. Patients also were evaluated by study-certified ophthalmologists who assessed ROP residua primarily in the posterior pole of the fundus, with unfavorable outcome be ing a posterior retinal fold or worse. Results: For the 247 children examined, both functional and structural prim ary outcomes showed fewer unfavorable outcomes in treated vs control eyes: 44.4% vs 62.1% (P < .001) for distance visual acuity and 27.2% vs 47.9% (P < .001) for fundus status. Near acuity results were similar to those for di stance (42.5% vs 61.6%; P < .001). Total retinal detachments had continued to occur in control eyes, increasing from 38.6% at 51/2 years to 41.4% at 1 0 years, while treated eyes remained stable (at 22.0%). A previously distur bing subgroup trend that more control eyes than treated eyes had visual acu ity of 20/40 or better (in the 51/2-year report) was no longer present at 1 0 years- eyes that received cryotherapy were found at least as likely as co ntrol eyes to have 20/40 or better visual acuity. Conclusions: At 10 years, eyes that had received cryotherapy were much less likely than control eyes to be blind. A previous trend for a higher propor tion of sighted control eyes than sighted treated eyes to show acuity in th e normal range was not confirmed. The results show longterm value from cryo therapy in preserving visual acuity in eyes with threshold ROP.