Retina: Source of the Earliest Biomarkers for Alzheimer's Disease?

Alzheimer's disease (AD) develops undiagnosed for 10-15 years due to the lack of early diagnostic biomarkers. Visual deficits are common and crippling in AD patients and histopathological alterations found in the retina and brain are similar. We hypothesize that subtle morphological and functional changes in microglial and neuronal activities, such as those recently reported in the hippocampus, may also occur in retina during the preclinical stages of AD. These alterations are likely much more accessible to modern imaging and electrophysiological exploration than those occurring in the hippocampus and therefore, may serve as the earliest diagnostic biomarkers for AD.