Prospective randomized evaluation of diode-laser and cryotherapy in prethreshold retinopathy of prematurity

Purpose: To study the efficacy of indirect diode laser photocoagulation and cryotherapy in prethreshold retinopathy of prematurity (ROP). Methods: Thirty-six eyes of 18 premature infants less than 34 weeks gestational age and/or less than 1600 g birth weight with prethreshold ROP were prospectively randomized to treatment with either indirect laser photocoagulation or cryotherapy. Prethreshold ROP was defined as any stage of ROP in zone I with plus disease; or stage 3 with three or more contiguous clock hours or five or more total clock hours of involvement of retina in zone II with plus disease but less than threshold disease. Regression of the ROP was assessed for a minimum period of 6 months. Results: Regression of ROP occurred in all 36 eyes (100%) in both groups. Conclusions: Excellent results are achieved if ROP is treated at the prethreshold stage with both indirect laser photocoagulation and cryotherapy. Although laser has definite advantages, cryotherapy can be considered as an alternative modality of treatment in developing countries due to economic reasons.