Multicenter Trial of Cryotherapy for Retinopathy of Prematurity: ophthalmological outcomes at 10 years.

OBJECTIVE

To evaluate outcomes at 10 years after randomization for eyes undergoing cryotherapy vs eyes serving as controls, for patients enrolled in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP).

METHODS

The randomized cohort originally consisted of 291 preterm children with birth weights less than 1251 g who developed a defined threshold of ROP severity in one or both eyes. Patients with bilateral threshold ROP (n = 240) were randomly assigned to receive cryotherapy to one eye and no cryotherapy to the other eye. Those with ROP of less severity than threshold in the 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 visual 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 being a posterior retinal fold or worse.

RESULTS

For the 247 children examined, both functional and structural primary 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 distance (42.5% vs 61.6%; P<.001). Total retinal detachments had continued to occur in control eyes, increasing from 38.6% at 5(1/2) years to 41.4% at 10 years, while treated eyes remained stable (at 22.0%). A previously disturbing subgroup trend that more control eyes than treated eyes had visual acuity of 20/40 or better (in the 5(1/2)-year report) was no longer present at 10 years; eyes that received cryotherapy were found at least as likely as control 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 proportion of sighted control eyes than sighted treated eyes to show acuity in the normal range was not confirmed. The results show long-term value from cryotherapy in preserving visual acuity in eyes with threshold ROP.