Area of peripheral retinal nonperfusion and treatment response in branch and central retinal vein occlusion

To evaluate the extent of peripheral retinal nonperfusion in retinal vein occlusion and to determine its effect on the severity of macular edema and response to treatment.

This prospective clinic-based cohort study included 32 consecutive patients with retinal vein occlusion and refractory macular edema evaluated using spectral domain optical coherence tomography and wide-field fluorescein angiography. Areas of ischemia were calculated as a percentage of the total visible retina (ischemic index), which was evaluated when macular edema was present (foveal central subfield >300 μm) and when edema had resolved (foveal central subfield ≤ 300 μm). Ischemic index was the main outcome measure.

The mean ischemic index at study enrollment was 14.8% and was larger when macular edema was present compared with when edema had resolved (14.8 vs. 10.3%, P < 0.001). Compared with those with less nonperfusion, patients with ischemic index >10% had thicker mean foveal central subfield on optical coherence tomography (520.8 vs. 424.5 μm, P = 0.029) and worse visual acuity (56.3 vs. 59 letters) with the presence of macular edema and experienced greater decrease in optical coherence tomography (296.1 vs. 165.3 μm, P = 0.019) and gain in visual acuity (12.4 vs. 0.9 letters, P = 0.036) in response to treatment.

The area of peripheral retinal nonperfusion is variable in patients with retinal vein occlusion and affects its clinical course and response to treatment.