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

PURPOSE: To report the structural and functional outcomes at a minimum of 7 years postmenstrual age after randomized treatment of threshold retinopathy of prematurity with laser ablation or cryotherapy. METHODS: Nineteen patients were entered into a prospective, randomized protocol, in which one eye received cryotherapy, while the other eye received diode laser photocoagulation. Asymmetric eyes were randomly assigned. Two patients have died, and seven were no longer available for 7-year outcome examinations, leaving 10 children for analysis. RESULTS: Six males and four females with a mean birthweight of 631 g and a mean gestational age of 24.8 weeks were examined. Eight were symmetrical cases and treated in both eyes. Of these, there were six concordant and two discordant structural outcomes. The laser-treated eyes had the favorable outcome in each instance. The geometric mean visual acuity of the paired eyes after laser photocoagulation was 20/33, and after cryotherapy it was 20/133 (P = .03). The mean refractive error was -6.50 diopters after laser photocoagulation and -8.25 diopters after cryotherapy (P = .27), although one of the cryotherapy eyes could not be refracted because of phthisis. CONCLUSIONS: Laser photocoagulation appears to be associated with a structural and functional outcome at least as good as cryotherapy 7 years after therapy. Visual acuity and refractive error data suggest that laser photocoagulation may have an advantage over cryotherapy.