PSEN1 and Alzheimer disease: In the retinas of fAD mice, several studies have reported Aβ plaques in the retina of APP/PS1 mice at the late stage (12–18 months of age) [29,30], while no changes in the level of Aβ were detected in the retina of 3 × Tg-AD mice at the early stage (4–8 months of age), but the level of p-Taus396 was significantly increased at 4 months of age [31].