Caffeine Consumption in Glaucoma Patients and Healthy Subjects

Who May Qualify: - age 18 to 90 years - diagnosis of primary open angle glaucoma (Mild, Moderate and Advanced) - healthy subjects with no eye disease Who Should NOT Join This Trial: - Diseases, ophthalmic or systemic, that are likely to affect OCTA results - greater than moderate cataract - nystagmus - inability to look at target - macular degeneration other than mild drusen or pigmentary changes - diabetic retinopathy - neovascular glaucoma or non-glaucoma optic neuropathies - current macular edema, prior laser to retina, inflammatory retinopathy or choroidopathy - keratoconus, corneal ectasia, central corneal scarring - rheumatologic diseases or Raynaud's phenomena - pregnant and lactating women - mental illness or alcohol addiction - pre-existing bladder symptoms, cardiac disease or sleep disorder - refractive spherical diopter greater than 5 or cylinder greater than 3 - possible tolerance to caffeine (drinking more than 1 cup coffee per day). Always talk to your doctor about whether this trial is right for you.