Glaucoma is a group of related diseases that damage the optic nerve, resulting in vision loss and possible blindness. Many people affected with glaucoma do not experience symptoms, and may not be aware that they have the disease until they have lost a significant amount of vision. With early detection and treatment, however, eyes can be protected against the serious loss of vision or blindness. Catching glaucoma at an early, treatable stage is one important reason to have regular, thorough eye examinations. A leading cause of blindness and visual impairment in the United States, glaucoma affects patients of all ages.
Risk Factors for Glaucoma
There are several factors, including the following, that increase the risk of developing glaucoma:
- Being older than 60
- Being of particular descent, such as African-American or Asian
- Having a family history of glaucoma
- Having elevated intraocular pressure
- Having poor vision, or other eye disorders or injuries
- Having certain medical conditions, such as diabetes
- Taking certain medications, such as corticosteroids, for prolonged periods
Patients with risk factors for glaucoma should be especially vigilant about having regular eye examinations.
Causes of Glaucoma
Certain diseases or conditions, including those below, can contribute to the development of glaucoma:
- Increased pressure within the eye
- Severe eye infection
- Injury to the eye
- Blocked blood vessels
- Inflammatory conditions of the eye
Glaucoma is considered primary if its origin is unknown, and secondary if it results from another medical condition.
Types of Glaucoma
There are several types of glaucoma. The two major types are primary open-angle glaucoma, in which fluid drains too slowly from the drainage channels (trabecula) of the eye, and angle-closure (narrow-angle) glaucoma, in which the trabecula become blocked. Other types of glaucoma, which occur much more rarely, include the following:
- Low-tension glaucoma
- Congenital glaucoma
- Secondary glaucoma
- Pigmentary glaucoma
- Pseudoexfoliation glaucoma
Approximately 95 percent of glaucoma patients suffer from open-angle glaucoma.
Symptoms of Glaucoma
It is important to remember that patients with early-stage glaucoma are usually asymptomatic. When symptoms occur, they vary depending on the type of glaucoma, and can occur in one eye or both eyes. The symptoms of open-angle glaucoma include the following:
- Dim or blurred vision
- Gradual loss of peripheral vision
- Tunnel vision (at advanced stages)
The symptoms of angle-closure glaucoma can be eye-related or systemic:
- Severe eye pain
- Nausea and vomiting
- Sudden visual disturbance
- Blurred vision
- Halos around lights
- Red eyes
Either type of glaucoma can be primary or secondary disorder.
Diagnosis of Glaucoma
The diagnosis of glaucoma is made after a comprehensive medical examination of the eye, and a review of the patient's medical history. Tests are conducted to confirm the diagnosis. Testing may include the following:
- Dilated-eye examination
- Visual field test (perimetry)
- Retinal evaluation
- Visual acuity test
Once glaucoma is diagnosed, treatment should begin as soon as possible to help minimize the risk of permanent vision loss.
Treatment of Glaucoma
There is no cure for glaucoma, so treatments, including those below, focus on relieving symptoms and preventing further damage.
Eye drops or oral medication may be used to either reduce fluid production in the front of the eye or to help drain excess fluid. Side effects of eye drops include redness, stinging, irritation and blurred vision. A common side effect of oral medications is fatigue. Medication requires regular use to keep eye pressure under control.
Trabeculoplasty, iridotomy and cyclophotocoagulation are laser procedures that aim to increase the outflow of fluid from the eye, or eliminate fluid blockages.
A trabeculectomy creates a new channel to drain fluid from the eye, and reduce the pressure that causes glaucoma. Surgery is performed only after medication and laser procedures have been unsuccessful.
Although people with early-stage glaucoma may not experience symptoms, prompt treatment is required to preserve their vision.