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

Arch Ophthalmol. 2001 Aug;119(8):1110-8. doi: 10.1001/archopht.119.8.1110.


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.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Child
  • Cohort Studies
  • Cryotherapy*
  • Female
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Very Low Birth Weight
  • Male
  • Retinal Detachment / physiopathology
  • Retinopathy of Prematurity / physiopathology*
  • Retinopathy of Prematurity / surgery*
  • Treatment Outcome
  • Visual Acuity / physiology*