Methods

Infants with bilateral high-risk prethreshold retinopathy of prematurity (ROP)(n= 317) had one eye randomized to early retinal ablative treatment and the fellow eye managed conventionally (control eye). In asymmetric cases (n= 84), the eye with high-risk prethreshold ROP was randomized to early or to conventional management. High risk was determined using a model based on the Cryotherapy for Retinopathy of Prematurity natural history cohort. The primary outcome was visual acuity assessed by masked testers using the Teller acuity card procedure. Structural examinations were performed at 6 and 9 months.

Results

Grating acuity results showed a reduction in unfavorable visual acuity outcomes with earlier treatment, from 19.8% to 14.3%(P<. 005). Unfavorable structural outcomes were reduced from 15.6% to 9.0%(P<. 001) at 9 months. Further analysis supported retinal ablative therapy for eyes with type I ROP, defined as zone I, any stage ROP with plus disease; zone I, stage 3 ROP without plus disease; or zone II, stage 2 or 3 with plus disease. The analysis supported a “wait and watch” approach to type II ROP, defined as zone I, stage 1 and 2 without plus disease, or zone II, stage 3 without plus disease. These eyes should be considered for treatment only if they progress to type I ROP or threshold.

Conclusion

Early treatment of high-risk prethreshold ROP significantly reduced unfavorable outcomes in both primary and secondary (structural) measures.