“…Remarkably, anatomical and functional alterations, such as the thinning of the ganglion cell and retinal nerve fiber layers [ 26 ], the presence of protein aggregates, and glial activation [ 27 , 28 , 29 ] can be detected in the postmortem evaluation of the retina in AD patients and animal models, thus strengthening the idea that the retina could be exploited in early AD diagnosis. Moreover, visual deficits, including difficulty reading [ 30 ], depth perception [ 31 ], and color recognition [ 32 ], are also reported in the early stages of AD. Changes in retinal structure and function have been reported in other neurodegenerative disorders, such as Parkinson’s disease (PD) [ 33 ].…”