Branch Retinal Vein Occlusion Causes Topographic Optic Neuropathy and Retrograde Maculopathy

Background To evaluate retinal ganglion cell (RGC) loss and axonal affection in branch retinal vein occlusion (BRVO).Methods 13 eyes of 12 non-glaucomatous BRVO patients were included. Thickness of peripapillary and macular retinal nerve fiber layer (pRNFL, mRNFL), ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer, outer and total retina were measured at baseline and after a mean follow-up of 14 months. We compared the thickness between the affected and their internal reference regions. Additionally, pRNFL thickness was compared between the occluded and the healthy fellow eyes in the 11 unilateral cases.Results Significant degeneration of the pRNFL was observed in the affected sector of the BRVO eyes (P < 0.01 versus reference sector and versus fellow eye). In contrast, mRNFL and GCIPL thickness showed no difference between affected and reference regions and no correlation with pRNFL thickness. Degenerative microcystic macular edema (MME) was present in 25% of the eyes with macular edema following BRVO.Conclusion Axonal degeneration occurs in pRNFL, which suggests that anterograde degeneration is the mechanism of RGC affection in BRVO. Our results emphasized the importance of pRNFL monitoring in BRVO treatment, and considering degenerative MME in persistent edema following BRVO.