Evaluating the causes of retinopathy of prematurity relapse following intravitreal bevacizumab injection

Background Retinopathy of prematurity (ROP) is a proliferative disorder of the developing retina. Intravitreal bevacizumab injection (IVB) is an emerging treatment for severe forms of ROP, which does not restrict the visual field in comparison to laser therapy. The present study aimed to determine and evaluate the risk factors for ROP recurrence following IVB injection. Materials and methods In this retrospective study, 98 eyes of 49 infants with ROP who had received IVB injections as the primary treatment for type 1 ROP are included. Results Fifty-four eyes (55.1%) had aggressive retinopathy of prematurity (A-ROP), and forty-four (44.9%) had Stage III Plus ROP in Zone II. ROP recurred in 13 eyes (13.26%) of 8 infants. The mean period between IVB and the ROP recurrence was 8.08 (95% CI:5.32-10.83) weeks. The infants who had ROP recurrence had lower birth weight (P value = 0.002), lower postmenstrual age at IVB injection (P value = 0.001), lower IVB injection gap period from birth (P value = 0.044), higher oxygen therapy requirement rate after IVB injection (P value < 0.001, OR:19.0) and higher oxygen therapy duration (P value = 0.006). The ROP severity, gestational age at birth, and diet were not statistically different between the recurrence and complete regression groups. Out of 13 eyes treated with laser photocoagulation because of ROP relapse, macula dragging occurred in one eye, and all the cases met the complete regression. Conclusion Low birth weight and oxygen therapy are the most important risk factors for ROP relapse, which requires meticulous oxygen treatment guidelines for premature infants.