MAPT and Alzheimer disease: Other studies involving the retina also discuss accumulation of phosphorylated tau in the brain, another biomarker of AD, and how this often relates to an accumulation of tauopathy in the retina in cases of AD (London et al., 2013; Chiasseu et al., 2017; Ashok et al., 2020; Hart de Ruyter et al., 2023).