What parts of the retina are examined to detect for Alzheimer’s?

We’re looking at the retina as visible brain tissue, and while we’re not sure what the right measure actually is yet, we are looking at the structure of the tissue, cell populations, vasculature, chemistry, physiology, and the marker that’s appropriate for what we want to look at in the retina to track the disease. One uncontrollable factor, however, is how when we look at the retina, we could be looking for different measures depending on the stage of the disease we’re interested in. We also have to interpret the images/scans reliably and understand what the best quantitative metrics are that we can cull from those images so we know that if we see a signal, that we can rely on it, that it’s repeatable, etc. This is a crucial study.