Randomized comparison of diode laser photocoagulation versus cryotherapy for threshold retinopathy of prematurity: 3-year outcome

Abstract

Purpose: To report the structural and functional outcomes at a minimum of 3 years postmenstrual corrected age following laser- or cryoablation of threshold retinopathy of prematurity (ROP).

Methods: Nineteen patients were entered into a prospective, randomized treatment protocol, in which one eye received cryotherapy and the other received diode laser photocoagulation. Asymmetric eyes were randomly assigned. Two patients have died and five were not available for 3-year outcome exams.

Results: Seven males and five females with a mean birthweight of 638 g and a mean gestational age of 24.9 weeks were examined. Two patients had asymmetrical disease and received laser photocoagulation. Two discordant structural outcomes were present among the 10 symmetrical cases. The laser-treated eyes had the favorable outcome; the cryotherapy-treated eyes had the unfavorable outcome. The geometric mean visual acuity after laser photocoagulation was 20/52; after cryotherapy, it was 20/91 (P = 0.046). The mean refractive error was -6.60 diopters (D) after laser photocoagulation and -7.62 D after cryotherapy. Seven patients (58%) have developed strabismus.

Conclusions: Laser photocoagulation appears to have an outcome at least comparable to cryotherapy when the patients are examined 3 years following therapy. These data, including visual acuity and refractive error, suggest that laser photocoagulation may have a minimal advantage over cryotherapy in the treatment of ROP.