This is an observational study designed to assess the reliability and consistency of the Optina awAIrTM CAS Test for detecting phenotypic changes in the retina that are associated with beta-amyloid status (positive or negative). The purpose of this study is to ensure that the retinal image capture process is consistent and under control, regardless of the operator or the time of measurement. The study will include enough repeated measurements on different systems, by three operators, and at different times to demonstrate.

The purpose of this study is to assess the reliability of the Optina Retinal Deep Phenotyping.TM(RDP) platform. The RDP Platform is comprised of the Optina-4CTM retinal camera and its Optina-4C ConnectTM software, as well as the Optina awAIrTM-CAS Test (also called CAS Test) for detecting phenotypic changes in the retina that are associated with cerebral beta-amyloid status (positive or negative). This study will quantify points of variability in the data input for the CAS Test, including:

• Left eye vs. right eye (retinal scan)
• Eye algorithm selection (eye assessment obtained from different eye specialists either an Ophthalmologist or an Optometrist)
• Hardware variability (Inter-instrument Variability retinal scans obtained from different Optina-4CTM cameras)
• Inter-operator variability (retinal scans obtained from different Users of the Optina-4CTM camera)
• Intra-operator variability (retinal scans obtained by the same user on the same Optina-4CTM camera

Inclusion Criteria:

• Male and female adults aged 50 years and older with vision in both eyes.
• Sufficient fluency in English or French to participate in study visits.
• Ability to give informed consent.
• Individuals with both eyes meet the eligibility criteria for retinal imaging.

Exclusion Criteria:

• Pupil dilation contraindicated (due to pathology, or presence of 3 quadrants with Van Herick grading of 0 or 1 without iridotomy).

• Inadequate pupil dilatation (< 6mm diameter) preventing uniform illumination of the retina with the Optina 4CTM camera.

• Diagnosis of glaucoma or signs of glaucoma (excavation ratio ≥0.7).

• Signs of vascular occlusion or retinopathy (microaneurysm, exudate, hemorrhage, or edema) within a diameter of 10 mm from the mid-point between the optic nerve head and the macula.

• Presence of drusen and/or age-related macular degeneration (AREDS 9-step scale

  ≥4 - cumulative drusen area diameter ≥ 250 µm, pigmentary changes and cumulative drusen area diameter ≥ 63 µm or pigmentary changes and cumulative geographic atrophy area diameter ≥ 354 µm).

• Nuclear sclerosis > 2 (LOCS II four-point grading system) or presence of central cortical or central posterior subcapsular cataract.

• Deficient visual fixation (inability to fixate for at least 2 s).

• Refractive error outside the range of -15 D to +15 D.

• Corneal or media opacities (e.g., Weiss ring) affecting retinal imaging on a cumulative area > 1 disc area within a diameter of 10 mm from the mid-point between the optic nerve head and the macula (i.e., the area of interest for the Optina 4CTM imaging)

• Scar, atrophy, naevus, tumor, epiretinal membrane or retinal pucker with a cumulative area > 1 disc area within a diameter of 10 mm from the mid-point between the optic nerve head and the macula.

• Papilledema and/or optic disc swelling.

• Macular anomaly (e.g., macular hole, dystrophy, degeneration).

• Inability to obtain up to 5 images or a minimum of 3 images of satisfactory quality with the Optina 4CTM per the Optina Diagnostics quality index software and /or per the eye specialists' evaluation. This exclusion criterion also applies if participants are unable to provide the required number of images during the second visit as well.

• Currently taking or has previously taken cerebral amyloid modifying medication.

Men and women 50 years and older who can undergo pupil dilation for both eyes and are not contraindicated for mydriatic imaging with a fundus camera.