The Outcome of Cryotherapy for Retinopathy of Prematurity (ROP) According to ROP Location

Cryotherapy has been shown to be an effective treatment for retinopathy of prematurity (ROP) stage 3+. However, the outcome of cryotherapy is less favorable in zone 1 ROP than in zone 2 ROP. We suspected whether there may be differences in the outcomes of cryotherapy if the zone of ROP is further divided. So we reviewed the records of 85 premature infants (145 eyes) who had undergone cryotherapy for ROP. The frequencies of favorable outcome were 42.9% of 14 eyes (zone 1), 78.9% of 38 eyes (posterior zone 2), 92.9% of 70 eyes (mid zone 2), and 100.0% of 23 eyes (anterior zone 2), respectively (p < 0.001). These results suggest that the more posteriorly the ROP is located, the less favorable the outcome of cryotherapy.