Glaucoma

What is Glaucoma?

The term "glaucoma" refers to a group of eye diseases that, if left untreated, can lead to permanent blindness. In fact, it is the number one cause of blindness in African-Americans, and the second leading cause of blindness overall in the United States.

If you're African-American, you're 6 to 8 times more likely to be diagnosed with glaucoma, and 14 to 17 times more likely to go blind from the disease than Caucasians. The good news is that with early detection and treatment, glaucoma can be controlled before it causes major vision loss.

There are many different types of glaucoma, and they can affect all age groups. One glaucoma patient may have sudden pain and redness, while another has no symptoms at all. In many cases, by the time symptoms are evident (such as peripheral vision loss), damage can be permanent. It is important to learn as much as you can about glaucoma and to have your eyes examined by your doctor on a regular basis.

There are several different kinds of surgeries available to treat various types of glaucoma. Generally, the doctor won't recommend surgery until medication has been tried first. And even after surgery, medication may still be needed to control your intraocular pressure.

Argon Laser Trabeculoplasty (ALT)

A laser delivers a highly focused, powerful beam of light used to make a very small opening in the eye tissue that allows fluid to drain out. Most laser surgeries are performed in the doctor's office. The doctor numbs the eye first, and there is rarely any other pain. Sometimes sedating medication is also delivered through an injection or intravenous line. There may be a slight stinging sensation with some forms of laser surgery, but no major pain.

Argon laser trabeculoplasty (ALT) is primarily used to treat primary open-angle glaucoma (POAG). As the patient sits facing the laser, the doctor holds a special lens to the eye. A high-energy beam of light is aimed at the lens and reflected onto the trabecular meshwork drainage system inside the eye. The patient may see flashes of bright green or red light. The laser makes 50-100 evenly spaced burns, which enlarge the drainage channels in the trabecular meshwork drainage system to assist in fluid drainage. Generally, this surgery occurs over two sessions, with half the fluid channels treated each time.

Studies find the laser trabeculoplasty lowers eye pressure in about 75 percent of treated patients. But the effects of treatment may wear off over time. Two years after laser surgery, the pressure increases again in more than half of all patients. If this happens, further laser treatment may not work. A similar surgery, selective laser trabeculoplasty (SLT), treats specific cells "selectively," leaving untreated portions of the trabecular meshwork drainage system intact. Thus, it's believed this type of surgery can be repeated several times.

Conventional Glaucoma Surgery

This type of surgery, called trabeculectomy or filtering microsurgery, is generally performed only after medicine and laser surgery fail. In conventional surgery, the surgeon makes a new opening for fluid to leave the eye. The surgery is usually performed in a hospital or outpatient surgery center under local anesthesia. The surgeon removes a tiny piece of the wall of the eye, called the sclera, leaving a tiny hole through which the aqueous fluid can drain out under the conjunctiva.

Sometimes the surgeon places a small tube or valve in the eye, which acts as a regulator for the buildup of fluid (and resulting pressure) within the eye. If the IOP reaches a certain level, the valve opens, allowing the fluid to flow out of the interior of the eye to be reabsorbed by your body. Drops must be instilled in the eye for several weeks after the operation to fight infection and inflammation. Frequent visits to your surgeon may also be needed for follow-up. Surgery is initially effective in about 80 to 90 percent of patients at lowering pressure. However, if the new drainage opening closes, a second operation may be needed.

Conventional surgery works best if a previous eye surgery, such as a cataract operation, has not been performed. Although most studies show the surgery is effective in 70-90% of cases for at least one year, it doesn't improve sight. In fact, vision may not be as good as it was before surgery. Also, sometimes the channel created during the surgery closes up and pressure builds again. Anti-wound healing drugs may help slow down the healing. The surgery can also be repeated several times if necessary. Like any operation, glaucoma surgery can have side effects or complications. These include cataracts, problems with the cornea and inflammation or infection inside the eye. The surgery itself carries risks—infection, bleeding, undesirable changes in IOP or vision loss. However, if any of these problems are experienced, treatments for them are available.

Laser Peripheral Iridotomy

This laser surgery is often used to treat closed-angle or narrow-angle glaucoma. The surgeon uses the laser to make a small hole in the iris—close to the drainage angle—which enables fluid to move more freely within the eye and prevents the iris from plugging the trabecular meshwork drainage system.