MAPT and Alzheimer disease: To explore the presence and burden of tau tangles in the AD retina, we utilized anti-MC-1 immunostaining and Bielschowsky silver staining in retinal cross-sections from a subset of donors with MCI (n = 9, mean age 89.7 ± 5.1 years, 5 females/4 males), AD (n = 21, mean age 86.1 ± 8.4 years, 11 females/10 males), and NC controls (n = 18, mean age 84.5 ± 9.3 years, 9 females/9 males), comparing them to brain NFTs (Fig. 1, extended data in Suppl.