Glaucoma is the name for a group of eye diseases that damage the optic nerve. This nerve carries information from the eye to the brain. When the nerve is damaged, you can lose your vision.
Glaucoma is one of the most common causes of legal blindness in the world. At first, people with glaucoma lose side (peripheral) vision. But if the disease isn't treated, vision loss may get worse. This can lead to total blindness over time.
There are three types of glaucoma.
- Open-angle glaucoma (OAG) is the most common form in the United States and Canada. (In other parts of the world, it's less common.) It usually affects both eyes at the same time. Your vision gradually gets worse. But it gets worse so slowly that you may not notice it.
- Closed-angle glaucoma (CAG) isn't very common in the U.S. and Canada. It usually affects one eye at time. CAG can happen suddenly and be a medical emergency.
- Congenital glaucoma is a rare form of glaucoma that some infants have at birth. Some children and young adults can also get a type of the disease.
The exact cause isn't known. Experts think that increased pressure in the eye (intraocular pressure) may cause the nerve damage in many cases. But some people who have glaucoma have normal eye pressure.
Some people get glaucoma after an eye injury or after eye surgery. Some medicines (corticosteroids) that are used to treat other diseases may also cause glaucoma.
If you have OAG, the only symptom you are likely to notice is loss of vision. You may not notice this until it is serious. That's because the eye that is less affected makes up for the loss at first. Side vision is often lost before central vision.
Symptoms of CAG can be mild, with symptoms like blurred vision that last only for a short time. Severe signs of CAG include longer-lasting episodes of blurred vision or pain in or around the eye. You may also see colored halos around lights, have red eyes, or feel sick to your stomach and vomit.
In congenital glaucoma, signs can include watery eyes and sensitivity to light. Your baby may rub his or her eyes, squint, or keep the eyes closed much of the time.