The goal of this study is to create new retinal imaging processing software useful for the development of novel retinal biomarkers of cognitive impairment associated with Alzheimer's disease (AD).

Inclusion Criteria:

1. Result of the standard neuropsychological assessment
2. Are men or postmenopausal women, at least 55 years of age. Postmenopausal women are defined as women who have had a hysterectomy and/or bilateral oophorectomy; or who have been amenorrheic for at least 2 years;
3. Fluency in English
4. Participants in mild cognitive impairment (MCI)/prodromal and mild-to-moderate dementia groups must assign a surrogate for purposes of informed consent and help with protocol compliance.

Exclusion Criteria:

1. Known or suspected diagnosis of non-AD, associated dementia;
2. Major ophthalmologic comorbidities: Ruptured globe, retinal vascular occlusive disease, retinal artery occlusion, anterior ischemic optic neuropathy, media opacification due to corneal abnormalities or cataract that prevent ocular and OCT examination, glaucoma, wet (neovascular) age-related macular degeneration, history of intravitreal injections, and macular edema. If two eyes satisfy the inclusion criteria, both eyes will be included in the study.

Normal controls and patients with mild, mild to moderate cognitive impairment