Another key characteristic sign of AD neuropathology that strongly reflects neuronal injury and cognitive decline is abnormal tau, specifically hyperphosphorylated tau and its inclusion in NFTs (Iqbal et al., 2009; Buckley et al., 2017; Hanseeuw et al., 2019). The physiological distribution pattern of total non-phosphorylated tau expression in the human retina was first described in 1995 (Loffler et al., 1995). According to this report and subsequent studies, tau is predominantly expressed in the inner retinal layers, most intensely along three distinct bands in the IPL, more diffusely in the OPL and somatodendritically in the INL (Loffler et al., 1995; Leger et al., 2011). Tau is also localized, albeit weakly, in other inner retinal layers such as the GCL and NFL as well as in photoreceptors of the human retina (Loffler et al., 1995; Leger et al., 2011).