What is glaucoma?

Glaucoma is a group of eye diseases that has one thing in common: progressive (increasing) damage to the vision nerve (optic nerve) that connects the eyeball to the brain.

This damage is recognized by a loss of optic nerve tissue in a pattern called "cupping," and by blind spots or blurry spots in the peripheral (side) vision. Advanced glaucoma can lead to permanently blurred or dimmed vision, or even to blindness. Early and moderate stage glaucoma generally has no symptoms. This is why it is important to be examined by an ophthalmologist (eye doctor) regularly to determine if you are likely to develop the disease.

In many cases, we do not know exactly what causes glaucoma. However, increased eye pressure is the most common risk factor for developing the disease. The pressure comes when the clear fluid in the eye, called the aqueous humor, does not drain properly.

This fluid normally helps to nourish the eye, and flows in and out of the eye through a mesh-like channel. In people with high eye pressure, the fluid does not drain properly and pressure builds up in the eye.

However, it is possible to develop glaucoma even if your eye pressure is normal. Currently, treatment for glaucoma is aimed at lowering your eye pressure, even if it is “normal.”

Glaucoma treatment cannot restore vision that is lost. But treatment can reduce the likelihood of additional vision loss. That is why screening and early detection of glaucoma are so important.

What are the different types of glaucoma?

There are 2 main types of glaucoma found in adults:

  • Open-angle glaucoma is the most common type. It is found in approximately 90% of glaucoma patients in the United States. In open-angle glaucoma, the structures in the eye appear to be normal, but fluid does not drain properly, probably because of changes in and along the drainage passage. This type of glaucoma has no early warning signs and can go unnoticed for years.
  • Chronic or acute angle-closure glaucoma accounts for about 10% of glaucoma cases in U.S. Here, the normal drainage passage in the eye is narrowed and then becomes blocked.

If either type of glaucoma is diagnosed early enough, a simple laser treatment can be used to improve the drainage.

Who is most likely to get glaucoma?

Glaucoma is more commonly found in people over the age of 35. You are more likely to get glaucoma if you:

  • Are of African-American descent.
  • Have family members with glaucoma.
  • Have diabetes.
  • Have had a serious eye injury in the past.
  • Take corticosteroid (e.g., prednisone) medications.

Glaucoma usually occurs in both eyes, although one eye may be more affected than the other.

What are the symptoms of glaucoma?

Most patients with glaucoma do not notice any symptoms at first, until they have lost some of their peripheral (side) vision. Often, this is not recognized by the patient until the disease has progressed.

When other symptoms are present, they may include:

  • Pain in the eye. (IMPORTANT: If you have sudden, severe eye pain, headache, and blurred vision, your internal eye pressure may be very high. You should call your ophthalmologist or go to an emergency room right away.)
  • Redness in the eye.
  • The vision in one or both eyes appearing hazy.
  • Seeing halos around lights.
  • Narrowing of vision (tunnel vision).

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