APP and Alzheimer disease: Post-mortem analysis of the eyes from human donors and the APP/PS1 and other mouse models of AD, which mimics human AD pathology through overexpression of APP and deposition of Aβ brain plaques, have shown APP and/or Aβ accumulation in the retina (Ning et al., 2008; Shimazawa et al., 2008; Dutescu et al., 2009; Liu et al., 2009; Perez et al., 2009; Kam et al., 2010; Park et al., 2014; Gupta et al., 2016; Hadoux et al., 2019).