Atlas of Retinal Imaging in Alzheimer's Study

Inclusion Criteria (ALL PARTICIPANTS): * · Individuals between the ages of 55 and 80 years old (inclusive). * Permitted medications stable for at least 1 month prior to screening. In particular: * Participants may take stable doses of antidepressants lacking significant anticholinergic side effects (if they are not currently depressed and do not have a history of major depression within the past year). * Adequate visual and auditory acuity to allow neuropsychological testing, as determined by the eye exam and the neuropsychologist's judgment. Hearing augmentation by hearing aids is allowed. * Good general health or without any clinically significant abnormalities (see exclusion criteria) that would be expected to interfere with participation in the study. * Participants must be willing and able to provide written informed consent. * Participants must have a study partner (i.e., family member, close friend, or caregiver) who can attend study appointments with them and report on their level of daily functioning. * As this is entirely an observational study, without treatment intervention, we will allow concurrent enrollment in other clinical trials for mild cognitive impairment (MCI) or AD, including those that involved the use of investigational drugs. Relevant information about other studies in which participants are participating (e.g., study name, sponsor) will be collected and considered as a potential statistical covariate in the statistical analysis plan …