Aging & Health A to Z
Causes & Symptoms
Glaucoma is usually caused when the pressure of the fluid inside the eye increases. Here’s how that happens: A liquid called intraocular fluid (aqueous humor) is produced inside the eye and fills the cavity behind the eye’s lens. Normally, this drains out through the eye’s drainage system. But when you have glaucoma, the fluid either drains too slowly or stops draining altogether. It’s not clear why this happens. When it does, the intraocular fluid builds up and increases pressure inside the eye. This damages the optic nerve and causes vision loss.
The Most Common Forms of Glaucoma
There are several forms of glaucoma. The two most common are:
- Open-angle glaucoma. This is the leading form of glaucoma. It occurs when intraocular fluid drains too slowly, increases pressure inside the eye and, over time, damages the optic nerve. Because damage to the optic nerve occurs slowly and doesn’t cause pain, there are no warning signs. By the time you notice vision problems, you may have significant vision loss. Open-angle glaucoma usually affects your side (peripheral) vision first. But it can also affect your central vision. Untreated, it can ultimately cause blindness.
- Angle-closure glaucoma. In this form of glaucoma, intraocular fluid drainage is either partly or completely blocked, so fluid in the eye builds up, increasing pressure on and damaging the optic nerve. Angle-closure glaucoma causes relatively slow damage if drainage is partly blocked. But if drainage is completely blocked, severe and rapid damage and vision loss may result. This is a medical emergency and requires immediate treatment.
Warning signs of a form of glaucoma that can cause rapid and serious vision loss include:
- extreme eye pain
- vision loss
- blurred vision
- seeing colored rings around lights
- redness in the eye
- a "hazy" appearance to the eye
- nausea or vomiting.
How Common is Glaucoma?
Your odds of developing glaucoma increase as you get older. About 1 in 20 adults 65 and older develop glaucoma. Roughly 1 in 10 adults 80 and older develop the disorder.
You run a higher than average risk of developing glaucoma if you have these factors:
- Age older than 60. The older you are, the higher your risk.
- Ethnic background, if you are of black or Asian heritage. Glaucoma is the leading cause of blindness in black Americans.
- Genetics. Glaucoma “runs in your family.”
- Pre-existing eye conditions. For example, you already have poor vision, a thin cornea, previous severe eye injury, or other eye problems.
- Other health conditions. You have diabetes, high blood pressure, or heart disease.
- Medication history. You’ve used corticosteroids drugs, such as prednisone, for long periods of time. In particular, ophthalmic corticosteroid drops or ointments are associated with increased risk of glaucoma.
Updated: November 2016
Posted: March 2012