There are two main types of glaucoma: Open-angle glaucoma and Closed-angle glaucoma. Open-angle glaucoma accounts for most cases. It is painless and the only signs are gradual loss of peripheral vision and optic nerve changes. Closed-angle glaucoma accounts for a small percentage of glaucoma cases. Closed-angle glaucoma symptoms include sudden eye pain, halos around lights, red eye, increased eye pressure, nausea and a sudden loss of vision. Closed-angle glaucoma is considered an eye emergency and should be handled by a professional to prevent permanent vision loss.

Routine eye exams include a screening for glaucoma using a machine called a tonometer. The tonometer is used to measure the pressure inside your eye. One of the most common tonometers use a puff sent onto the surface of the eye to test the internal pressure. Another method of glaucoma screening involved advanced imaging technology that monitors the eyes optic nerve over the course of your exams to ensure that no changes have occurred. Visual field testing is another way to determine loss of peripheral vision. It involves staring ahead while holding a button that will allow you to click when you see a flashing light in the edges of your vision. The test catches any blind spots that may develop as a result of damage to the optic nerve as a result of glaucoma.