The present invention describes methods to image amyloid beta in the retina of the eye in such a way as to diagnose and potentially treat Alzheimer's disease. The preferred apparatus to perform the image and treatment is described. The basic idea is to use an imaging method to characterize the depth location of amyloid beta (hereafter referred to as A&bgr；) in the retina, to classify and characterize the type of deposit, to quantify the amount present and thereby to diagnose Alzheimer's disease and stage the disease. The methods describe herein include image guided treatment of A&bgr； deposits in the retina.
