Glaucoma is a group of eye diseases that gradually steals sight without warning or without symptoms. This loss of vision is caused by damage to the optic nerve. The nerve is responsible for carrying the images we see to the brain. It was once thought that high intraocular pressure (IOP) was the main cause of this optic nerve damage, we now know that other factors must also be involved because even people with “normal” IOP (intraocular pressure) can experience vision loss from glaucoma.
The most common types of glaucoma include primary open angle glaucoma, angle closure glaucoma, secondary glaucoma, normal tension glaucoma, pigmentary glaucoma, and cataracts and glaucoma. The most common type of glaucoma is primary open angle glaucoma, affecting about three million Americans. Open angle glaucoma presents no symptoms or early warning signs, so detection is crucial. This type of glaucoma develops slowly and causes a gradual loss of vision. Fortunately, it usually responds well to medication, especially if caught early and treated.
What are the symptoms?
There are typically no early warning signs or symptoms of open-angle glaucoma. It develops slowly and sometimes without noticeable sight loss for many years.
Most people who have open-angle glaucoma feel fine and do not notice a change in their vision at first because the initial loss of vision is of side or peripheral vision, and the visual acuity or sharpness of vision is maintained until late in the disease.
By the time a patient is aware of vision loss, the disease is usually quite advanced. Vision loss from glaucoma is not reversible with treatment, even with surgery.
Who’s at risk?
Glaucoma can occur in anyone. The chance of developing glaucoma increases if you are African-American or Hispanic; have a family history of glaucoma; are very nearsighted; are over 35 years of age; have diabetes and/or hypertension, and/or any vascular diseases.
How is it diagnosed?
Tonometry – A technician will use a special device that measures the eye’s pressure.
Ophthalmoscopy – used to examine the inside of the eye, especially the optic nerve. In a darkened room, the doctor will magnify your eye by using a magnifying lens to look at the shape and color of the optic nerve.
Perimetry – During this test, you will be asked to look straight ahead and then indicate when a moving light passes your peripheral (or side) vision. This helps draw a “map” of your vision.
Gonioscopy – a painless eye test that checks for open or closed angle glaucoma.
Nerve Fiber Layer Analyzer – uses a computerized machine which takes pictures of your nerve fiber layer.
How is it treated?
Medicines – Glaucoma is generally treated with eye drops and/or pills. Glaucoma medications must be taken as prescribed to be effective. Side effects will be discussed when the medications are given.
Laser Surgery – More and more often, laser surgery is being employed as a primary or supportive form of treatment. The eye is first numbed with drops, then the laser beam is applied to the trabecular meshwork in the doctor’s office. The procedure takes only a few minutes and results in improving the rate of drainage. If the laser surgery is successful, it may reduce the need for additional eye drops or, possibly, even reduce the need for current eye drops.
Filtration Surgery – If medications and laser are unsuccessful in controlling the eye pressure, filtration surgery can be performed. During this procedure, a new drainage channel is formed to allow fluid to drain from the eye to remove pressure.
Canal-based surgery – Canal-based surgery may be necessary if other treatment modalities fail. During this procedure, the existing drainage system can be stented or opened up to enhance drainage and potentially lower pressure.