Abstract
Purpose: :
Intravitreal bevacizumab (IVB) is known to be effective for the resolution of macular edema associated with branch retinal vein occlusion (BRVO-ME), although the mechanism remains unclear. IVB, an anti-vascular endothelial growth factor (VEGF) antibody, suppresses vascular hyper-permeability, thus influencing retinal blood flow. The purpose of this study is to evaluate the changes in retinal blood flow and macular thickening after the use of IVB in eyes with BRVO-ME.
Methods: :
Thirty eyes with BRVO-ME, without any previous treatment, received 1.25mg/0.05ml of IVB. Fourteen eyes had superior temporal vein occlusion and the other 16 eyes had inferior temporal vein occlusion. Retinal blood flow was evaluated using relative flow volume (RFV) as measured by laser speckle flowgraphy of the occluded vessels, as well as of intact vessels, every week for 12 weeks after IVB injection. Central macular thickness (CMT) was measured by optical coherence tomography and best-corrected visual acuity (VA) using a logMAR chart were also evaluated during the clinical course.
Results: :
After treatment with IVB, the RFV of the occluded vessels decreased significantly for the first 4 weeks, showing a decrease of 90.6±2.3 % in the arteries, and 94.3±6.2 % in the veins at 4 weeks. The RFV of the occluded vessels then returned to the initial levels by 12 weeks. The RFV of the normal, non-occluded arteries and veins was unchanged during the 12-week clinical course. CMT and VA both improved up to 4 weeks after IVB treatment and their improvement corresponded to the RFV changes seen at the occluded vessels.
Conclusions: :
The regression of macular edema seen with IVB injections of patients with BRVO-ME corresponded to the reduction of blood flow in the occluded vessels, indicating the efficacy of IVB on occluded vessels. IVB did not influence the blood flow of the intact vessels, indicating that IVB is a safe and effective treatment for BRVO-ME.
Keywords: vascular occlusion/vascular occlusive disease • vascular endothelial growth factor • imaging/image analysis: clinical