What is Glaucoma?
Glaucoma is a disease that damages the optic nerve. Over 3 million Americans (65 million people worldwide) are affected by glaucoma. Half of those with glaucoma are not aware of it. Glaucoma has been called the “silent thief of sight” because there are no warning signs until significant nerve damage and vision loss has occurred.
As the optic nerve degenerates, blind spots develop in the peripheral (side) vision. Because the blind spots are usually in the outer visual field, they go unnoticed. The most common cause of nerve damage is high intraocular pressure (eye pressure). Once the nerve is damaged, it cannot be replaced or repaired. With early detection and proper treatment, total blindness from glaucoma is uncommon.
Who Is At Risk For Glaucoma?
Everyone has some risk of glaucoma. It is important for everyone to have routine eye exams to look for the early signs of glaucoma. The risk for glaucoma is increased with these factors:
- Higher eye pressure
- A family history of glaucoma
- African-American, Asian, or Hispanic descent
- Over 45 years of age
- Past eye injury
- Severe nearsightedness
- Other medical conditions – diabetes, migraines, poor circulation
- Use of steroid medications
What Causes Glaucoma?
There are many causes of glaucoma, some we understand and some we do not. The most common cause is high intraocular pressure. The eye is full of fluid called the aqueous humor. The eye is constantly making and draining this fluid. Fluid is drained out of the eye through a filter, called the trabecular meshwork. If the filter (meshwork) in the eye is clogged, fluid cannot drain properly and the eye pressure rises. As the eye pressure rises, it pushes on the optic nerve and can cause the nerve to be damaged.
There are 2 main types of glaucoma that are named for the different ways fluid outflow is reduced:
- Open-Angle Glaucoma is the most common type of glaucoma in the United States, Europe, and Africa. In open-angle glaucoma, the meshwork appears normal but does not allow fluid to pass through adequately.
- Closed-Angle Glaucoma is more common in Asia than in the United States. In closed-angle glaucoma, the iris blocks the meshwork decreasing the outflow of fluid from the eye. This can rapidly increase eye pressure causing pain and immediate loss of vision. This can also happen slowly without pain and casuse a gradual loss of vision.
