Retinal fluorescein angiographic changes following intravitreal anti-VEGF therapy

To describe the retinal vascular morphology in eyes injected with intravitreal bevacizumab for treatment-requiring retinopathy of prematurity (ROP).

In this prospective, nonrandomized case series, fundus photographs and fluorescein angiography in patients diagnosed with stage 3 threshold or prethreshold ROP, were obtained immediately before and 1 month after injection of 0.03 cc (0.75 mg) of intravitreal bevacizumab using wide-field digital pediatric imaging system.

A total of 47 eyes of 26 patients were included. Before treatment, fluorescein angiography showed vascular abnormalities, including capillary nonperfusion throughout and shunting in the vascularized retina, demarcation line, limited vessel development, new vessels leakage, avascular periphery and absence of foveal avascular zone. After intravitreal bevacizumab, fluorescein angiography showed involution of the neovascularization, flattening of the demarcation line and subsequent growth of vessels to the capillary-free zones. During the following weeks large areas devoid of microvessels were seen as well as vascular remodeling with uneven spacing of the retinal capillaries and vascular loops in the areas that were previously devoid of vessels. In some patients, retinal vessels in the far periphery never developed: patients with these findings did not subsequently develop pathological neovascularization.

In this study cohort, patients showed improvement of their abnormal vascular findings after intravitreal bevacizumab, however even when the vascular pattern remained abnormal, there was creation of small vessels, establishment of directional flow, maturation of retinal vessels, and adjustment of vascular density.