Revascularization of immature retinas with retinopathy of prematurity using combination therapy of deferred laser treatment after a single intravitreal bevacizumab injection

Background: This study aimed to observe the extent of retinal vascularization in patients with retinopathy of prematurity (ROP) who underwent deferred laser treatment (LT) after a single intravitreal bevacizumab injection (IVB).Methods: This study retrospectively evaluated 40 consecutive eyes in 21 infants who received a single IVB or LT. Deferred LT was performed in cases of ROP recurrence after a single IVB. To assess the amount of retinal vascularization between the initial IVB and deferred LT, the cases were divided into three groups based on treatment: single IVB, deferred LT after a single IVB, and prompt LT. The growth and associated complications were compared between groups.Results: There were 12, 16, and 12 eyes in the single IVB, deferred LT, and prompt LT groups, respectively. Deferred LT was performed at an average of 7.9 weeks after a single IVB. In the single IVB group, retinal vascularization proceeded to zone III, whereas the prompt LT group did not show any growth of vascularization beyond the laser scars. In the deferred LT group, during the window period before LT, retinal vascularization progressed from zone I to zone II posterior and from zone II posterior to zone II anterior, respectively, without further ROP recurrence. Conclusions: Retinal vascularization progressed during the deferred window period, thereby reducing the area of the retina ablated by LT. A single IVB followed by deferred LT can be an alternative treatment option to prevent ablation of zone I or multiple IVBs.