Introduction
Different Types of Glaucoma
Laser Treatment for Open-Angle Glaucoma
Laser Treatment for Narrow-Angle Glaucoma
Laser Cyclophotoablation
Summary
Glaucoma is one of the leading causes of permanent blindness in the world, affecting more than two million Americans, and more than one hundred million people worldwide. It is a disease of the optic nerve, which is the nerve that connects your eye to your brain. Glaucoma takes away its victim’s sight slowly, but relentlessly, and in most cases, without any warning. Visual damage from glaucoma is irreversible and permanent. Blindness from glaucoma, however, can be prevented with proper preventive eye care. There are laser treatments that are effective in the treatment of glaucoma as well, and these treatments are discussed below.
The most common type of glaucoma is open-angle glaucoma. Open-angle glaucoma means that there is no visible obstruction to the drainage area inside the eye. It is thought that there may be an invisible obstruction to fluid drainage in the trabecular meshwork, which is the structure in the eye that drains the fluid. This type of glaucoma typically causes no symptoms until the damage and visual loss is very advanced.
Narrow-angle glaucoma, less common than open-angle glaucoma, involves a narrowing of the drainage area of the eye. This narrowing is caused because the iris of the eye moves closer to the drainage area in predisposed individuals. If the iris moves so close that it closes the drainage area, then the intraocular pressure increases, and narrow-angle glaucoma is the result. This type of glaucoma is most common in persons of Chinese and Vietnamese descent, and less common in persons of African and Caucasian descent. However, it can affect a person of any race. It may cause symptoms of sudden pain, redness, blurred vision, and colored haloes around lights. This condition is called acute narrow-angle glaucoma, and must be treated immediately. Failure to treat this condition immediately can cause permanent loss of vision. Sometimes narrow-angle glaucoma is a chronic condition that does not cause any symptoms, like open-angle glaucoma
Laser Treatment for Open-Angle Glaucoma
Health
Open-angle glaucoma may be treated with a laser in an attempt to lower the pressure inside the eye. This treatment usually involves minimal discomfort, and is completed in fewer than 30 minutes. This laser is generally effective in about 80 percent of patients who undergo the procedure. Sometimes the beneficial effect of the laser is not permanent. In approximately 50 percent of patients, the laser helps to lower pressure for as long as ten years.
It is usually performed in the office with topical anesthetic drops. The laser is attached to a machine that is similar to the one that your ophthalmologist (eye doctor) uses to examine your eyes. During the laser procedure, the patient sees multiple bright flashes of light, and may occasionally feel a mild stinging sensation in the eye. Usually, however, the patient doesn’t experience pain. In laser treatment for open-angle glaucoma, the laser beam is directed toward the drainage area of the eye (trabecular meshwork) between the cornea and the iris. In some types of glaucoma, there is an invisible blockage in the trabecular meshwork that blocks the outflow of fluid, thereby increasing the pressure inside the eye. It has been discovered that treating the trabecular meshwork with a laser can lower the pressure inside the eye. It is thought that the laser increases the flow of fluid through this drain.
Many times, your ophthalmologist will treat only one half of the drainage area with the laser treatment. One reason for this is to decrease the risk of possible complications from the laser. Possible complications include an actual increase in the eye pressure, or inflammation inside the eye. These two complications are normally treated with eye drops. If treatment of one half of the drainage area works to lower the pressure, then treatment to the other half of the drainage area can be performed at a later date if the eye pressure rises.
After laser treatment for open-angle glaucoma, the complete effect may not be noticed until about six weeks after the procedure. Glaucoma medications should be continued following laser treatment unless your ophthalmologist instructs you otherwise.
Laser Treatment for Narrow-Angle Glaucoma
Laser treatment for narrow-angle glaucoma can be used to prevent an attack of narrow-angle glaucoma, and it can also be used during an attack, in order to lower the eye pressure. The laser is used to create a tiny microscopic hole in the iris of the eye, so that fluid may pass through this hole. This allows the iris to fall back away from the drainage area. This usually prevents or cures narrow-angle glaucoma.
The treatment is usually performed in the office with topical anesthetic drops. It can usually be completed in fewer than thirty minutes and involves minimal discomfort for the patient. The laser is attached to a machine that is similar to the one your ophthalmologist uses to examine your eyes. During the procedure, the patient will notice multiple bright flashing lights, and may experience occasional stinging in the eye—much like laser surgery for open-angle glaucoma. Normally, the patient does not experience any discomfort.
After the laser treatment, your ophthalmologist will ask you to stay in the office for approximately one hour so that the eye pressure can be checked. Sometimes, you may be asked to return in 24 hours for a repeat pressure check. Usually, you will also be asked to return in one week for another pressure check and assessment of the treatment.
This treatment is approximately 98% effective in preventing narrow-angle glaucoma. The treatment used during an attack of narrow-angle glaucoma is about 85% effective in stopping the attack. In cases where the laser does not work, treatment with medicines or microsurgery will be necessary.
Another type of laser treatment for both open-angle and narrow-angle glaucoma is called cyclophotoablation. This procedure directs the laser to the ciliary body of the eye, which is the part of the eye that produces fluid. The ciliary body is located behind the iris. The laser destroys part of the ciliary body so that less fluid is produced inside the eye, thereby lowering eye pressure.
Since the ciliary body is located behind the iris of your eye, it is not readily visible and accessible for laser treatment. For this reason, the laser cyclophotoablation procedure must be performed using either an endoscope or a special probe that focuses the laser energy through the sclera, which is the white shell of the eye. The endoscope is a tiny, one millimeter flexible telescope which is inserted through a small incision in the eye, and which allows the surgeon to see and precisely direct the laser treatment to the appropriate area. The other probe is designed to focus the laser treatment on the appropriate area, but the surgeon cannot actually see the treatment as it takes place.
Because cyclophotoablation destroys part of the eye in order to decrease eye pressure, many surgeons consider it a destructive procedure, and only recommend this treatment as a last resort for treatment of advanced glaucoma. The endoscopic laser treatment may be less destructive to the eye since the surgeon controls it more precisely. Some surgeons use this endoscopic laser treatment at the time of cataract surgery if the patient has glaucoma, even if the glaucoma is not advanced.
This treatment is effective in lowering the eye pressure about 90% of the time, though oftentimes, multiple treatments are necessary.
Laser surgery can be very effective treatment for glaucoma. It is usually a quick and relatively painless procedure and frequently is performed right in the office. It is also covered by most types of medical insurance.
