The investigators will capture images of the participant's retina using the XyCAM RI or XyCAM FC (test data) and by color fundus photography, optical coherence tomography (OCT), and standard automated perimetry (SAP) - the standard clinical data. The investigators will perform five tests. The first two tests will be conducted using the XyCAM RI or XyCAM FC to obtain test data. The final two tests will be conducted using routine clinical instruments to obtain standard clinical data. The investigators will administer eye drops (Tropicamide) to dilate the participant's pupils prior to the first test. Tropicamide is a chemical that causes pupil dilation and is commonly used by doctors to examine the participant's eyes. The entire set of test data sessions should last less than eighty (80) minutes with an additional 60 minutes for carrying out the necessary procedures and imaging using the standard clinical data.
The goal of this clinical trial is to investigate the use of an FDA-cleared retinal blood flow imaging instrument called the XyCAM RI and XyCAM FC (Vasoptic Medical, Inc., Columbia, MD) in glaucoma management.~The main question it aims to answer are:~Can the investigators use blood flow to discriminate between eyes with early-stage glaucoma and variable-matched controls?~Can the investigators validate that the XyCAM FC simultaneously captures both stereo fundus photography and ocular blood flow monitoring?~Participants will be~measured for their blood pressure, heart rate, height, and weight~dilated with tropicamide~imaged using the XyCAM RI, fundus photography, optical coherence tomography, and standard automated perimetry~imaged using the XyCAM RI while inhaling 100% oxygen through a mask