To evaluate the association between the size of peripheral retinal non-perfusion and the number of intravitreal ranibizumab injections in patients with treatment naïve central retinal vein occlusion (CRVO).

Fifty-four patients with treatment-naïve CRVO and macular edema were included. Each patient underwent a full ophthalmologic examination including optical coherence tomography (OCT) imaging and ultra wide-field fluorescein angiography (UWFA). Monthly intravitreal ranibizumab injections were applied according to the recommendations of the German Ophthalmologic Society (DOG). Two ophthalmologists quantified the areas of peripheral retinal non-perfusion (group 1= less than 5 disc areas, group 2= more than 5 disc areas). Correlation analyses between the size of non-perfusion with best corrected visual acuity (BCVA), central subfield thickness (CST) and the number of intravitreal injections were performed.

BCVA improved significantly after intravitreal injections (P<0.001, both groups). Final CST after treatment did not significantly differ between both groups (P= 0.92, P=0.96, respectively). Mean number of injections in group 1 and group 2 was 4.12 + 2.73 and 9.32 + 3.84, respectively (P< 0.001). There was a significant positive correlation between areas of non-perfusion and the number of injections in each group. (R= 0.97, P<0.001, R= 0.94, P<0.001, respectively).

Peripheral retinal non-perfusion in patients with CRVO correlates significantly with the number of needed intravitreal ranibizumab injections. UWFA is a useful tool for detection of peripheral retinal ischemia, which may have direct implications in the diagnosis, follow-up and treatment of these patients.