Objective: To compare the efficacy of intravitreal injection of ranibizumab (IVR) monotherapy and laser therapy for treatment-requiring retinopathy of prematurity (ROP) in Zone II.

Methods: A prospective, randomized, controlled single-center trial was applied from January 2014 to December 2014; infants who were diagnosed as Zone II treatment-requiring ROP (i.e., Zone II Stage 2 or 3 ROP with plus disease) were randomly assigned to receive IVR monotherapy or laser therapy, and the follow-up interval was at least 6 months. Any eyes that developed recurrence of ROP underwent crossover re-treatment.

Results: A total of 100 eyes of 50 ethnic Han Chinese infants were enrolled. At the last follow-up, 26 eyes of 13 infants developed recurrence of ROP in the IVR group and 2 eyes of 1 infant developed recurrence of ROP in the laser therapy group. There was a significant statistical difference in the rate of ROP recurrence between IVR and laser therapy to treat Zone II treatment-requiring ROP (P = 0.001).

Conclusions: Although IVR appears to regress ROP to certain levels and continue to promote the vascularization of peripheral retinal vessels, a substantial proportion of infants developed recurrence of ROP after a single-dose IVR. Therefore, IVR is not recommended as a single-dose monotherapy for Zone II treatment-requiring ROP.