Objective: To determine whether earlier treatment of high-risk, prethreshold retinopathy of prematurity (ROP) improves retinal structural outcome at 2 years of age.
Methods: Infants with bilateral high-risk prethreshold ROP had one eye randomly assigned to treatment with peripheral retinal ablation. The fellow eye was managed conventionally, and either treated at threshold ROP or observed if threshold was never reached. In patients with asymmetrical disease, the high-risk, prethreshold eye was randomised to earlier treatment or to conventional management. At 2 years of age, children were examined comprehensively by certified ophthalmologists to determine structural outcomes for their eyes. For the purposes of this study, an unfavourable structural outcome was defined as (1) a posterior retinal fold involving the macula, (2) a retinal detachment involving the macula or (3) retrolental tissue or "mass" obscuring the view of the posterior pole. Results of the 2-year examination were compared with those from the 9 months examination.
Results: Data were available on 339 of 374 (90.6%) surviving children. Unfavourable structural outcomes were reduced from 15.4% in conventionally managed eyes to 9.1% in earlier-treated eyes (p = 0.002) at 2 years of age. Ophthalmic side effects (excluding retinal structure) from the ROP or its treatment were similar in the earlier-treated eyes and the conventionally managed eyes.
Conclusion: The benefit of earlier treatment of high-risk prethreshold ROP on retinal structure endures to 2 years of age, and is not counterbalanced by any known side effect caused by earlier intervention. Earlier treatment improves the chance for long-term favourable retinal structural outcome in eyes with high-risk prethreshold ROP. Long-term follow-up is planned to determine structural and functional outcomes at 6 years of age.