Video: National Institutes of Health (NIH)
Glaucoma is an eye disease that gradually destroys the optic nerve tissue in the back of the eye. The greatest danger of glaucoma stems from the fact that the disease is painless and without obvious symptoms until more than 50% of the optic nerve has died. The most common cause is from pressure being too high inside the eye, but vascular disease and other diseases can also cause glaucoma. We check for glaucoma during routine eye examinations. Tests include checking the pressure of the eye, screening for peripheral vision defects, and analyzing the appearance of the optic nerve. If you are diagnosed with glaucoma, we typically prescribe 1 or more medications that lower the eye pressure to preserve vision. Most forms of glaucoma are successfully treated with eye drops, but for those cases that are not, additional tools include laser treatments and eye surgery, which offer alternative ways to treat more advanced glaucoma.
In open-angle glaucoma, pressure increases in the eye occur due to clogged or blocked passages. Fluid that normally drains through these passages begins to build up, and the increased pressure can damage the optic nerve. Open-angle glaucoma tends to develop without warning, often painlessly and with no symptoms. Because of this, it can cause damage and blindness more quickly when untreated. Risk factors for developing glaucoma include people over the age of 40, those who have a family history of glaucoma, those who are very nearsighted, and those with diabetes.
In closed-angle glaucoma, the pressure of the eye becomes elevated due to the inability of the aqueous fluid to drain properly because the iris prevents the fluid from reaching the anterior chamber drainage tissue (trabecular meshwork). The drainage tissue functions normally, but the iris blocks the passage of the fluid. If this form of glaucoma is suspected your doctor may order optical coherence tomography (OCT) of the angle and/or perform a procedure called gonioscopy to help visualize the angle.