Understanding & Testing for Glaucoma
Glaucoma is an eye disease that slowly and painlessly steals away your sight. There are usually no symptoms associated with glaucoma. The disease typically does not cause redness or pain. It is the second leading cause of blindness in the United States, and half of the people who have glaucoma don’t know that they have the disease and are not aware that they are going blind.
The cause of glaucoma is unknown, but there are several risk factors that increase your risk of developing glaucoma. These include high eye pressure (called intraocular pressure, or IOP), older age, being African-American or Hispanic, and having a family history of glaucoma.
Anyone with any of these risk factors should get regular eye examinations to assess for glaucoma.
Glaucoma damages vision by destroying the optic nerve, which connects your eye to your brain, and carries visual information to your brain for processing. When the optic nerve is damaged from glaucoma, you lose your vision. Your peripheral vision—or side vision—is typically lost first. If the glaucoma remains untreated, the vision loss creeps in toward the center, first causing tunnel vision, and then, eventually, blindness.
The cause of optic nerve damage in glaucoma is not known, but since most eyes with glaucoma have high IOP, or high fluid pressure inside the eye. The eye is filled with clear fluid that flows in through a spigot and flows out through a drain. In glaucoma patients, either there is an overflow of fluid produced or the drain of the eye gets plugged, raising the IOP. It is likely that high IOP plays a role in damaging the nerve but it is not known for sure.
Testing for glaucoma includes the following:
- IOP measurement. At the Eye Care Center we have a very patient friendly screening device called the ICare tonometer that is very well received and does not blow a puff of air into the eye.
- Visual field test - A computer assisted device is used to test your peripheral vision.
- Gonioscopy – A specialized mirrored lens is used to assess your drainage outflow channels within the eye.
- Optical coherence tomography (OCT) – A specialized computer that images the optic nerve layers beneath the visible surface.
- Pachymetry – This test measures the thickness of the cornea which is important when interpreting the pressure in the eye.
If you are diagnosed with glaucoma, treatment is available to preserve your vision. The goal of glaucoma treatment is to lower IOP and stop the optic nerve damage. Several kinds of treatment are available to lower IOP. These include eye drops, laser therapy, and surgery. Eye drop medications lower IOP by either reducing the amount of fluid entering the eye or increasing the amount of fluid exiting the eye. Laser therapy is often used when medications fail to successfully lower IOP, and is also used for patients who cannot tolerate medications due to side effects. For some patients, laser therapy is used instead of medications. If medications and/or laser therapy fail to bring the IOP down to a safe range, surgery is available to lower IOP. Your doctor will work with you to develop a treatment plan that will safely lower your IOP.