Glaucoma

Background

Glaucoma is an eye disease that slowly and painlessly steals away your sight. Glaucoma is called the silent thief of sight because it has no symptoms—it does not make your eyes red or cause pain. But it is the second leading cause of blindness in the United States, and half of the people who have glaucoma don’t know that they have the disease and are not aware that they are going blind.

The cause of glaucoma is unknown, but there are several risk factors that increase your risk of developing glaucoma. These include high eye pressure (called intraocular pressure, or IOP), older age, being African-American or Hispanic, and having a family history of glaucoma. Anyone with any of these risk factors should get regular eye examinations to look for glaucoma.

Glaucoma damages vision by destroying the optic nerve, which connects your eye to your brain, and carries visual information to your brain for processing. When the optic nerve is damaged from glaucoma, you lose your vision. Your peripheral vision—or side vision—is lost first. If the glaucoma remains untreated, the vision loss creeps in toward the center, first causing tunnel vision, and then, eventually, blindness.

The cause of optic nerve damage in glaucoma is not known, but since most eyes with glaucoma have high IOP, it is likely that high IOP plays a role in damaging the nerve. IOP is a measure of the fluid pressure inside the eye. The eye is filled with clear fluid that flows in through a spigot and flows out through a drain. In glaucoma, the drain of the eye gets plugged, and fluid coming into the eye cannot get out, raising the IOP.

A thorough examination for glaucoma should include the measurement of IOP. But since some eyes can have glaucoma without high IOP, a careful examination of the optic nerve looking for glaucoma damage is also very important. If the IOP is high or the optic nerve looks damaged (or both), a special test called a visual field test should be performed. The visual field test shows whether or not you’ve lost any side vision to glaucoma.

If you are diagnosed with glaucoma, treatment is available to save your vision. The goal of glaucoma treatment is to lower IOP and stop the optic nerve damage. Several kinds of treatment are available to lower IOP. These include eye drops, laser therapy, and surgery.

Eye drop medications lower IOP by either reducing the amount of fluid entering the eye or increasing the amount of fluid exiting the eye. There are several different kinds of glaucoma medications, and each differs in terms of both its ability to lower IOP and its potential side effects. Laser therapy is often used when medications fail to successfully lower IOP, and is also used for patients who cannot tolerate medications due to side effects. Recent advances in laser therapy have produced lasers so safe and effective that for some patients, laser therapy is used instead of medications. If medications and/or laser therapy fail to bring the IOP down to a safe range, surgery is available to lower IOP.

We will work with you to develop a treatment plan that will safely lower your IOP.

Diagnosis

GDx Testing

A new laser technology which may revolutionize the early diagnosis of glaucoma is available for the first time in Lafayette at Williamson Eye Institute in Jefferson Square, the only site in Lafayette where the advanced sight-saving exam is currently available. The new laser instrument called GDx VCC Nerve Fiber Analyzer measures the nerve fiber layer, a thin layer of tissue surrounding the optic nerve, and has been found to be a more precise and accurate test than other technologies currently used to detect glaucoma. GDx VCC is especially valuable to screen for glaucoma. The current air puff test which only measures intraocular pressure to detect glaucoma fails for many people tested as studies show that numerous glaucoma sufferers have no elevation of pressure. Other common tests determine the presence of glaucoma only late in the course of the disease by measuring how much vision has already been lost.

"The new laser technology will have broad use in the future for those who desire accurate, rapid and cost-effective glaucoma detection," stated Robert T. Williamson MD. "As the population in the Lafayette area ages, glaucoma detection and treatment will become a much greater concern and it is vital to use technologies that effectively meet that need."

Dr. Williamson feels that consumers as well as eye care professionals need to be aware of this advanced technology as studies show over 50% of individuals with glaucoma aren't aware of it. "Glaucoma is a painless disease and is often referred to as the 'silent thief of sight' because many patients don't know they have a problem until significant vision has been lost," he explained.

The GDx VCC technology is also currently in use at prestigious eye institutions and research centers such as the Wilmer Eye Institute, University of Louisville, Stanford University, Balboa Naval Hospital in San Diego, CA, and University of Washington in Seattle.

Dr. Williamson stresses that the GDx examination is painless and usually does not require pupil dilation. He explained that the laser works by using polarized light to pass through the nerve fiber layer and measure 65,536 points on the tissue layer. The measurements are processed by a powerful computer that "maps" the nerve fibers and instantly compares them to a database of healthy glaucoma-free patients. A thinning of the fibers indicates glaucoma.

This test is especially helpful in diagnosing and following early glaucoma. It has already helped hundreds upon hundreds of patients. It helps us to stay on the cutting edge of modern day glaucoma diagnosis and treatment.

Visual Field Testing

Automated visual field testing has been used for many years to determine the presence and progression of any visual field loss due to glaucoma.

Optic Nerve Photography

Photographs of the optic nerve can be a valuable part of following glaucoma and the response to treatment. As glaucomatous damage progresses, the area of the central optic nerve where nerve fibers are not present (called the cup) increases.

Treatment

Pharmacologic Treatment (Drops)

Selective Laser Trabeculoplasty (SLT)

In SLT, laser treatment is applied to the drain of your eye in order to open it up and let fluid out, lowering the eye pressure and saving your sight. SLT treatment takes only a few minutes, is performed in the office (not the operating room), is safe, and effectively lowers eye pressure in most people. The treatment is approved by the Food and Drug Administration (FDA) for treating glaucoma, and is covered by essentially all insurance plans.

People who might benefit from SLT are described below.

• Eye pressure not controlled despite using one or more eye drop medications—if you have tried several medications and your eye pressure is still not under control, SLT may be the next step.
• Inability to tolerate eye drop medications—some people have medical problems that make using eye drop medications unsafe, and others may be allergic to the preservatives in bottles of eye drop medications.
• Inability to put eye drop medications in your eyes—if you have arthritis, or a tremor, or very poor vision, you might not be able to put the drops in your eye.
• Frequently forgetting to use your eye drop medications—if you often forget to put your drops in, your eye pressure may be going up and down a lot; these fluctuations in eye pressure can make glaucoma worse.
• Inability to afford your eye drop medications—many people have insurance that will cover SLT but will not cover medications. If you cannot afford your medications, SLT might be a more cost-effective way to control your glaucoma.
• Desire to reduce the number of eye drop medications you are using—if your eye pressure is controlled but you require several eye drop medications to keep it controlled, SLT might allow you to reduce the number of medications you are using for eye pressure.
• Desire to avoid starting eye drop medication therapy—if you have just been diagnosed with glaucoma, you may prefer to avoid eye drop medications entirely. SLT may help you accomplish this.

If any of these descriptions apply to you, ask your doctor if SLT is right for you.

Glaucoma Surgery

If glaucoma cannot be controled by drops or laser surgery, incisional surgery may be required. A procedure called a trabeculectomy can be performed to create an alternate pathway for aqueous fluid to exit the eye.