Glaucoma is a general term for a family of eye diseases that damage the optic nerve. The optic nerve is located in the back of the eye and relays information from the eye to the brain. Elevated pressure inside the eye creates stress on the optic nerve and if it is damaged, vision loss occurs.
Glaucoma is one of the leading causes of blindness in the United States. Early detection is of primary importance because there are usually no symptoms until permanent vision loss has occurred. If you are at risk, it is highly advisable that you schedule a comprehensive vision exam and let your optometrist or ophthalmologist know you are at risk for glaucoma.
Glaucoma Risk Factors
Risk factors for glaucoma include:
- Age 45 or older
- Family history of glaucoma
- History of injury to the eye
- African American
- History of steroid use, either in the eye (drops) or systemically (orally or injected)
- Nearsighted (myopic)
- Farsighted (hyperopic)
- History of elevated intraocular pressure
If glaucoma is detected in a comprehensive eye exam, your eye doctor will design a treatment plan especially for you. Your doctor will go over the treatment options available and make recommendations for which treatment or combinations of treatments are best for your specific condition.
Causes and Symptoms
When talking about glaucoma, the terms “open” and “closed-angle” are often used. The angle between where the iris and the cornea (clear part of the eye) meet is critical to maintaining normal eye pressure. The internal eye liquid is called the aqueous humor, and it circulates between the iris and the lens, moves through the pupil, and then drains into the trabecular meshwork (located at the base of the cornea). When the space between the iris and cornea becomes so narrow that the space is gone completely, it is known as angle closure.
Angle narrowing progresses over time as the natural lens thickens with age. Because of this, all closed-angle glaucoma patients begin with an open angle that progresses to a narrow angle and then to a closed angle.
Open-angle glaucoma is the most common form of glaucoma in the United States and has no initial symptoms, developing slowly over time. The disease begins when the drainage canals of the eye become clogged which elevates the internal pressure of the eye. This increase in pressure damages the optic nerve, and you generally will not experience any changes in vision until severe eye damage has already occurred. The two major symptoms of open-angle glaucoma are an altering of peripheral vision and tunnel vision (in the advanced stages).
Closed-angle glaucoma occurs because of the gradual progression of a narrow angle to the point where the eye’s internal fluid cannot get to the drain because it is too narrow. There are two types of closed-angle glaucoma, chronic and acute. Chronic closed-angle glaucoma occurs when the eye’s drainage angle narrows gradually, and slowly restricts the ability of the eye to drain fluid. The progression of this is often the same as open angle glaucoma. Acute closed-angle glaucoma occurs when the iris is not as wide and open as it should be, resulting in a sudden rise in intraocular pressure. Symptoms include severe headaches, nausea, vomiting, and blurred vision. These symptoms are intense and noticeable, and you must get medical attention immediately.
Your doctor will perform several tests to diagnose glaucoma. Most glaucoma is diagnosed through a routine pressure check using tonometry and an optic nerve evaluation which are parts of a comprehensive eye exam. Your doctor will check for optic nerve damage by looking directly through the pupil at the back of your eye to examine the shape and color of the optic nerve. A visual field test, cornea thickness measurement, and other tests can also help determine if you have glaucoma.