This is the most common type of glaucoma. Glaucoma is usually described as high pressure inside the eye that causes damage to the optic nerve over time. The mechanism of this damage is not entirely clear … but something about high pressure causes atrophy of the optic nerve over many years. The optic nerve is important because it connects the eyeball to the brain, and when damaged, the vision is permanently damaged. Most people with glaucoma have the “chronic open angle” variety, which is also called primary open angle glaucoma (POAG) or just plain “glaucoma.” It is believed that something microscopic clogs the drainage “filter” inside the eye, leading to chronically elevated pressure. Unfortunately, there is no single test to determine if someone has glaucoma, so we look at several risk factors to determine risk and monitor progress. This includes eye pressure (obviously), visual fields (to evaluate peripheral vision), and OCT photographs of the optic nerve looking for changes that might indicate progression. Treatment is geared toward lowering the eye pressure with medication eye drops, laser therapies (SLT), and even surgery in advanced cases.