A recent histological study confirmed the presence of retinal plaques in 6 AD patients and 6 healthy controls, including finding similar sized 12F4+Aβ42-containing deposits, and gave additional insight into the spatial distribution and subtypes of Aβ aggregates in the human retina (den Haan et al., 2018). Aβ-positive immunoreactivity and deposits were found in various cell layers in postmortem retinas of AD patients, particularly the INL; deposits were found within horizontal, amacrine, and Müller cells (den Haan et al., 2018). Analyses of retinal pathology in AD donors indicated that Aβ deposits were more abundant in the inner retinal layers, concentrating in the NFL and GCL (Koronyo et al., 2017). Aβ42 was present in both fibrillar and proto-fibrillar forms, confirmed with TEM and Birefringence (apple-green) of Congo red-stained retinas under polarized light (Koronyo et al., 2017). More recently, Aβ40 was quantified and mapped in a larger cohort of postmortem human AD retinas (n = 47), showing significant increases in both retinal vascular and abluminal Aβ40 in AD patients as compared with matched controls (Shi et al., 2020). Retinal Aβ40 was especially abundant in the inner retinal layers of the central retina. Increased Aβ40 in the retina of AD patients as compared with cognitively normal individuals was further validated by biochemical ELISA analysis (Shi et al., 2020).