Progression of retinal vascularization after intravitreal anti-vascular-endothelial growth factor therapy in retinopathy of prematurity

Background Anti-vascular endothelial growth factor (Anti-VEGF) therapy is now considered as one of standard therapies in approaching infants with retinopathy of prematurity (ROP). The purpose of this study was to assess the time to full retinal vascularization in infants with ROP who were treated with intravitreal bevacizumab (IVB). Methods This retrospective cohort study evaluated premature infants with ROP who were treated with IVB between 2012 and 2019. Demographic and clinical data were collected from the medical records and analyzed. Main outcomes were defined as time to complete vascularization and time of zone shift. Results Eight hundred sixty-five eyes from 441 patients were included. Average gestational age and birth weight were 28 +/- 4 weeks and 1121 +/- 624 g, respectively. Primary treatment failure and reactivation occurred in 35 eyes (4.0%) and 33 eyes (3.8%), respectively. Recurrent ROP occurred significantly more frequently in infants with pre-treatment zone 1 ROP compared to those with zone 2 ROP (7.6% versus 3%, p < 0.01). Patients with pre-treatment zone 2 reached zone 3 faster than those with pre-treatment zone 1 (142 +/- 152 days versus 181 +/- 174 days, p < 0.01); however, the time until full retinal vascularization did not significantly differ between the groups (p = 0.10). Conclusion This study revealed that pre-treatment ROP zone was associated with ROP reactivation rate but not with time to full vascularization in those treated with IVB. Trial registration Retrospectively registered; IR.TUMS.FARABI.REC.1399.040