Comparison of Vascular Outgrowth Rate and Retinal Vascular Development Border after Intravitreal Injection of Aflibercept or Bevacizumab to Treat Retinopathy of Prematurity

Abstract

Purpose: It is aimed to evaluate vascular outgrowth rate (VOR) of retinal vessels and retinal vascular development border (RVDB) after intravitreal injections of aflibercept or bevacizumab (IVA or IVB) monotherapy, which have been used to treat retinopathy of prematurity. Methods: In this study, patients were followed by two sequential fluorescein angiography (FA) examinations (Ret-Cam III Imaging System Clarity Medical Systems, Pleasanton, CA, USA) after anti-VEGF monotherapy. RVDB was determined by the ratio between DB (the distance from the center of the disk to the RVDB) and DM (the distance from the center of the disk to the center of the macula). On the other hand, VOR was calculated by the following novel formula: VOR = (DB/DM on the second FA) – (DB/DM on the first FA)/time between two FA examinations. Results: Fifty-one eyes of 27 infants who received aflibercept were included as group 1; 38 eyes of 19 patients who received bevacizumab were included in group 2. There were no significant differences between these groups in terms of demographic variables, percentages of disease at zone 1 and posterior zone 2 (p = 0.260), as well as stage 2+ and stage 3+ disease (p = 1.0) at the time of anti-VEGF injections. VORs, which had been measured in between two sequential follow-up FAs, were estimated to be significantly higher in group 1, both in nasal (p = 0.042) and temporal sides (p = 0.033). However, DB/DM ratios were significantly higher in group 2 in the first FA (p = 0.001 at nasal and temporal sides) and the second FA examinations (p = 0.007 and p = 0.004 at nasal and temporal sides, respectively). Conclusion: VOR was found to be significantly higher in patients who were treated with IVA monotherapy. Paradoxically, RVDB was farther in patients receiving IVB monotherapy despite a slower VOR in these patients.