MAPT and Alzheimer disease: By extending previous studies on the presence of epitope-specific phosphorylation and accumulation of tau in the eyes of AD subjects [15, 76] and transgenic mouse models [6, 63, 77–80], these results show that protein cleavage is a pathological alteration detectable in ocular samples of 6-month-old Tg2576 AD animals, as previously shown for the brain parenchyma [57].