Glaucoma is a group of eye diseases that gradually decrease vision by damaging the optic nerve. It is most often associated with an increase in the intraocular pressure (IOP). It affects millions of Americans and is one of the leading causes of blindness in America. It is estimated that over half of those who have glaucoma do not know they have it. African-Americans are at particular risk for having the disease. It can be hereditary and its incidence and severity increases with age.
How do you know if you have glaucoma?
Glaucoma does not have any early symptoms. When it becomes symptomatic, the disease is usually in advanced stages. This is because it occurs very gradually and affects peripheral vision first. If you are over 35 and have a history of glaucoma in your immediate family, you should be evaluated for glaucoma. Patients over 50 years of age should also have a complete medical eye exam to rule out this silent disease.
Testing for glaucoma
The tonometry test measures the inner pressure of the eye. Usually drops are used to numb the eye. Then the doctor or technician will use a special device that measures the eye’s pressure.
Ophthalmoscopy is used to examine the inside of the eye, especially the optic nerve. The doctor will look at the shape and color of the optic nerve.
If the pressure in the eye is not in the normal range, or if the optic nerve looks unusual, then one or two special glaucoma tests will be done. These two tests are called perimetryand gonioscopy.
- The perimetry test is also called a visual field test. During this test, you will be asked to look straight ahead and then indicate when a light is seen in your peripheral (or side) vision. This helps draw a “map” of your vision. It is a good indicator of the amount of vision loss you have from glaucoma.
- Gonioscopy is an eye test that checks if the angle where the iris meets the cornea is open or closed, showing if either open angle or closed angle glaucoma is present. The angle is where fluid drains out of the eye, thereby controlling the pressure.
Optical coherence tomography is a new method to measure the health of the optic nerve. During this two-minute test, a light is used to measure the thickness of the nerve layer in the back of the eye. Sequential measurements over months or years can then be compared to see if the glaucoma damage is stable or getting worse.
Treatment of Glaucoma
Glaucoma can be treated in many ways. Most often the disease can be controlled with eye drops to decrease the intraocular pressure. Laser therapy is usually the next step in the process. This treatment is done in our office and is relatively painless. The eye is anesthetized with eye drops only and the drainage part of the eye is lasered using tiny burst of energy. This enables the eye to drain the fluid more effectively and thereby reduces the eye pressure.
The final stage in the treatment of glaucoma is surgical intervention. During glaucoma surgery a new communication is created between the inside of your eye and the outside. This new drain is called a filter or a “bleb”. If surgery is successful, one can often have low pressures and stable vision without the use of eye drops.