Types of Glaucoma Surgery
There are two general types of glaucoma surgery. Depending on the kind and severity of a patient’s glaucoma, a doctor will suggest either laser treatment or conventional surgery, which involves making an incision in the eye to reduce the intra-ocular pressure.
Doctors usually suggest laser surgery before conventional surgery (filtering microsurgery) unless the optic nerve is severely damaged or the eye pressure is extremely high. Laser surgery increases the fluid flow out of the eye by using a concentrated beam of light to treat the trabecular meshwork (the eye’s drainage system). Depending on the type of glaucoma a patient has and how advanced the glaucoma is, the doctor will choose one of the several kinds of laser surgeries that exist to treat glaucoma.
Before laser glaucoma surgery, the patient should arrange for someone else to drive them home. Laser glaucoma surgery is and outpatient procedure, which means the patient will be able to return home the day of the surgery. The surgery is typically performed in the eye doctor’s office or and eye clinic, and directly before the surgery the eye will be numbed with medicine.
During laser surgery, generally, the eye is numbed to keep the patient from feeling most or any of the pain associated with the surgery, and the doctor then holds a specific lens to the eye. The doctor points the laser beam into the eye, and similar to a camera flash, there is a bright light.
The most common type of laser surgeries for treating glaucoma include:
- Selective Laser Trabeculoplasty (SLT)
- Argon Laser Trabeculoplasty (ALT)
- Micropulse Laser Trabeculoplasty (MLT)
- Laser Peripheral Iridotomy (LPI)
- Laser Cyclophotocoagulation
The patient may feel a faint stinging sensation during ALT or LPI laser surgery.
Conventional Glaucoma Surgery (Filtering Microsurgery)
The doctor may recommend conventional surgery, known as filtering microsurgery, when laser surgery is not successful in reducing the eye pressure or the pressure starts to increase again.
Before filtering microsurgery, the patient should arrange for someone else to drive them home. Laser glaucoma surgery is and outpatient procedure, which means the patient will be able to return home the day of the surgery. Patients are also given relaxation medication prior to surgery.
During filtering microsurgery, the patient usually feels no pain, because the operation is typically performed under local anesthetic. Often, limited anesthesia, also known as I.V. sedation, is used. Additionally, an injection is given behind or around the eye to inhibit eye movement. The patient does not feel pain from this injection when I.V. sedation is administered first. During the operation, the patient will be groggy. The formal name for the procedure is called a trabeculectomy or sclerostomy.
During filtering microsurgery a drainage hole is made in the sclera (white part of the eye) with a small surgical tool. The new opening permits the intra-ocular fluid to bypass the blocked drainage canals and out of this new, substitute drainage canal. If imperative, glaucoma surgery can be performed multiple times without considerable risk.
Risks and Complications of Glaucoma Surgery
Possible risks and complications associated with either laser or conventional glaucoma surgery include:
- Uncharacteristically high or low eye pressure
- Vision loss
- Increased development of cataracts
The majority of complications associated with glaucoma surgery can be treated successfully. The potential benefits of the surgery typically override the risks.
Recovering From Laser Glaucoma Surgery
After laser glaucoma surgery, the eye may feel slightly irritated and vision may become a bit blurry. Following surgery, medications are required in most cases to control and maintain eye pressure. Surgery may decrease the amount of medication needed, however. Generally, patients are able to return to their normal level of activity the day after laser surgery.
Recovering From Conventional Glaucoma Surgery (Filtering Microsurgery)
Within a few days after the surgery, the patient will return to the doctor to be checked for any signs of infection or inflammation increase.
Usually, patients must keep water out of their eye for, at minimum, one week following surgery. Patients must keep from driving, bending, reading, or lifting anything heavy during this time, but most normal activities can be resumed.
Shortly after filtering microsurgery, the eye will be irritated and red, and the eye may begin watering or tearing more than usual. The intraocular eye fluid will flow through the artificial new hole and create a small blister like clump called a bleb. The bleb is covered by the eyelid and typically, is not visible.
After surgery, the patient may experience some vision changes, including blurred vision, for approximately six weeks following surgery. After six weeks, vision will usually return to the patient’s pre-surgery vision level, but in some cases vision may improve, for patients using pilocarpine eye drops.
The patient may also need to change their contact lenses or glasses. Soft or gas permeable contact lenses may be worn, but in some cases, the bleb may cause fitting issues. Special care is required to keep the bleb from becoming infected, and contact users should talk to their doctor about these possible problems after surgery.
Outcomes of Glaucoma Surgery
Outcomes of Laser Glaucoma Surgery: Laser glaucoma surgery lowers the intra-ocular pressure of the eye, and is successful specifically, in around 75% of patients who undergo ALT laser surgery. In general, how long or to what degree the eye pressure remains lower after the surgery depends on the type of glaucoma, type of laser surgery performed, race, age, and multiple other factors.
Outcomes of Conventional Glaucoma Surgery (Filtering Microsurgery): In older patients, glaucoma filtering surgery is effective for approximately 70-90% of patients, for one year at minimum. Once in a while, the artificial drainage hole, created during surgery, starts to close and the pressure increases again. This occurs because the body recognizes the new opening as an injury in the eye and tries to heal the surgically created hole. This most frequently occurs in younger people, because their healing system is more powerful. Anti-wound healing drugs can be used to slow down the healing of the opening, and if necessary, glaucoma filtering surgery can be performed several times in the same eye.