Glaucoma Surgery

Argon laser trabeculoplasty (ALT) involves a laser to deliver a highly focused, powerful beam of light to make a very small opening in the eye tissue, allowing 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.

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 this 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 that laser trabeculoplasty lowers eye pressure in about 75 percent of treated patients. But its effects sometimes 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, 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. Glaucoma 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 glaucoma 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 to 90 percent 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 glaucoma 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.

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.

An acute attack of closed-angle glaucoma is a medical emergency requiring immediate treatment to lower eye pressure (IOP). As soon as the IOP drops to a safe level, the doctor will likely perform a laser iridotomy. Since it is common for both eyes to suffer from narrowed angles, laser surgery may be performed on the unaffected eye as a preventive measure.

This type of glaucoma surgery is often used to treat more advanced or aggressive cases of glaucoma. Certain areas of the ciliary body (the part of the eye that produces the aqueous liquid) are destroyed to reduce fluid production.