Multicenter trial of cryotherapy for retinopathy of prematurity. 3 1/2-year outcome--structure and function. Cryotherapy for Retinopathy of Prematurity Cooperative Group. Measurement of Goldmann visual fields in older children who received cryotherapy as infants for threshold retinopathy of prematurity.
Cryotherapy for Retinopathy of Prematurity Cooperative Group Reports from the 3- and 12-month follow-up examinations in the Multicenter Cryotherapy for Retinopathy of Prematurity trial indicated a beneficial effect of cryotherapy in the treatment of severe retinopathy of prematurity. This report provides results from the 3 1/2-year follow-up examination on 92% of the 256 survivors from the original cohort of 291 infants in the randomized trial. Functional outcome was evaluated by masked assessment of letter acuity using the HOTV crowded letter test and grating acuity using the Teller Acuity Card procedure. Structural outcome was evaluated by physician's assessment of retinopathy of prematurity residua in the posterior pole. All three outcome measures showed a reduction in unfavorable outcomes in treated vs control eyes: 46.6% vs 57.5% (P < .01) for letter acuity, 52.4% vs 65.6% (P < .001) for grating acuity, and 26.1% vs 45.4% (P < .001) for posterior pole status. These results support the long-term efficacy and safety of cryotherapy in the treatment of severe retinopathy of prematurity. Cryotherapy administered to eyes with severe acute-phase (threshold) retinopathy of prematurity benefits retinal structure and visual acuity compared with the natural course of the retinopathy.
                To determine the extent of peripheral field abnormalities in eyes with threshold retinopathy of prematurity that had retinal structure preserved by cryotherapy.
                Kinetic perimetry was performed with a Goldmann perimeter by masked testers on patients in whom bilateral threshold retinopathy of prematurity developed and who had been randomly assigned to undergo cryotherapy in one eye and no cryotherapy in the fellow eye. With the V-4-e and the II-4-e targets, eight meridians were tested: 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. The median value of three presentations in each meridian was accepted as the extent in that meridian.
                Fourteen eyes (eight treated and six control) of eight patients (mean age, 9.9 years; range, 6 to 11 years) had adequate vision to undergo fields testing. Mean (+/-SE) extent of visual field for treated vs control eyes was 36 degrees +/- 3 degrees vs 46 degrees +/- 6 degrees for the II-4-e target and 49 degrees +/- 4 degrees vs 59 degrees +/- 6 degrees for the V-4-e target. This difference was consistent across all eight meridians for either target, and repeated-measures analysis of variance showed that cryotherapy was associated with smaller visual field extent for both target sizes (P=.08).
                The results of this small pilot study suggest that eyes that have retinal structure and acuity preserved by cryotherapy for severe acute-phase retinopathy of prematurity have slightly smaller visual fields than untreated eyes with severe acute-phase retinopathy of prematurity that had vision preserved.
Peripheral retinal ablation reduces the incidence of adverse ophthalmic outcome in premature infants with threshold ROP. In sighted eyes, peripheral retinal ablation may reduce the size of the visual field. At this stage, long term outcomes remain unknown.