MAPT and Alzheimer disease: These peripheral retinal subregions, which have anatomically fewer ganglion cells and a thinner nerve fiber layer, appear more vulnerable to RGC loss in AD, potentially due to a higher density of abnormal Aβ and tau species (e.g., Aβ42, Aβ oligomers, PHF-tau, pS396-tau, and pS202/T205-tau), and microgliosis [63, 64, 73, 112].