Adaptive Optics Retinal Imaging

Inclusion Criteria: 1. Are 21 years of age or older. 2. Have the ability to cooperate with instructions during adaptive optics imaging (similar to instructions given during a clinical eye exam). 3. Have the ability to understand and sign an informed consent. 4. Have been diagnosed with POAG (cohort 2). Exclusion Criteria: 1. Are under 21 years of age. 2. Have a condition which prevents adequate images from being obtained (e.g. unstable fixation or media opacity). 3. Have visual correction outside of the range +4 diopters (D) to -8 D. 4. Have a history of adverse reaction to mydriatic drops. 5. Have a predisposition to (i.e., narrow iridocorneal angle) or any history of acute angle closure glaucoma (AACG). 6. Do not meet the criteria for POAG as defined by the American Academy of Ophthalmology Practice Patterns (cohort 2) 7. Have any health conditions that would contraindicate oxygen supplementation, including chronic obstructive pulmonary disease (COPD), emphysema, asthma, or any other obstructive or restrictive lung disease (RBF experiment participants only). 8. Have a dependency on oxygen support or a baseline oxygen saturation \<95% (RBF experiment participants only). 9. Have tested positive for COVID-19 at initial enrollment or have acute or chronic photophobia as a result of contraction. 10. Are working under the direct supervision of Dr. Hammer.