Glaucoma is a group of related diseases that damage the optic nerve, resulting in vision loss and possible blindness. Glaucoma, a leading cause of blindness and visual impairment in the United States, can affect patients of all ages. Many people affected with glaucoma do not experience any 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 thorough eye examinations regularly.
Risk Factors for Glaucoma
There are several factors that increase the risk of developing glaucoma, including:
- Being over 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, like diabetes
- Taking certain medications, such as corticosteroids for prolonged periods
Patients with risk factors for the disorder should be especially vigilant about having regular eye examinations.
Causes of Glaucoma
Certain diseases or conditions can contribute to the development of glaucoma. These include:
- 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, which occurs when the trabecula become blocked. Approximately 95 percent of glaucoma patients suffer from primary open-angle glaucoma. Other types of glaucoma, which occur much more rarely, include:
- Low Tension Glaucoma
- Congenital Glaucoma
- Secondary Glaucoma
- Pigmentary Glaucoma
- Pseudoexfoliation Glaucoma
Symptoms of Glaucoma
It is important to remember that patients with early stage glaucoma are most often 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:
- Dim or blurred vision
- Gradual loss of peripheral vision
- Tunnel vision (at advanced stages)
The symptoms of angle-closure glaucoma encompass systemic, as well as eye symptoms, including:
- Severe eye pain
- Nausea and vomiting
- Sudden visual disturbance
- Blurred vision
- Halos around lights
- Red eyes
Either type of glaucoma may be a 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 some of the following:
- Dilated eye examination
- Visual field test (perimetry)
- Retinal evaluation
- Visual acuity test
Once glaucoma has been 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 treatment focuses on relieving symptoms and preventing further damage. Some of the treatment methods for glaucoma are as follows:
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 the medication may result in redness, stinging, irritation or blurred vision. Regular use of the medication is needed to keep the eye pressure under control.
Trabeculoplasty, iridotomy, or cyclophotocoagulation are laser procedures that aim to increase the outflow of fluid from the eye or eliminate fluid blockages.
A trabeculectomy may be used to create 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.
While patients with early stage glaucoma may not experience any symptoms, prompt treatment is required to preserve their vision.