Dear Editor:

First, we commend the authors for comparing two different anti-VEGFs in the treatment of retinopathy of prematurity. We would like them to address our concerns related to their study. In the study, two patient groups, to which 0.25 mg ranibizumab and 0.625 mg bevacizumab were administered, were compared. It was reported in the study that the recurrences in the earlier period occurred because the half-life of ranibizumab is short and the recurrences in the later period occurred because the half-life of bevacizumab is long⁽¹⁾. In the cases in which bevacizumab was administered, recurrence was observed less frequently, but it had to be followed-up for longer period of time⁽¹⁾.

In this study, both anti-VEGFs were found to be effective for type 1 ROP. It appears that ranibizumab was administered to all of the zone 1 ROP patients in the study, as described in table 1, and bevacizumab was not used. We would like to know what criteria were used for medicine administration choices for the zone 1 cases. On the other hand, when the cases in which bevacizumab was administered were compared with the cases in which laser was used, the high myopia rate was significantly lower⁽²⁾. In a comparable study, a significantly higher chance of high myopia was noted in the bevacizumab group than in the ranibizumab group⁽³⁾. Although the refraction results were not reported in the study, we would like to know if there is a notable characteristic refractive error in terms of high myopia in the cases.