Glaucoma surgery is surgery to lower pressure inside the eye.
Reasons for Procedure TOP
It is done to treat glaucoma. The inside of the eye is normally bathed by a clear fluid. The fluid flows in and out of the front chamber of the eye. In most cases of glaucoma, this fluid flows too slowly out of the eye. The fluid builds up and increases the pressure inside the eye. If this pressure is not controlled, it can cause damage to the eye and loss of vision. This surgery is done to lower the amount of pressure in the eye. Decreasing the pressure may be needed to prevent further loss of vision.
It is important to note that while glaucoma surgery may save your remaining vision, it does not improve or restore sight.
Possible Complications TOP
Complications are rare, but no procedure is completely free of risk. If you are planning to have glaucoma surgery, your doctor will review a list of possible complications, which may include:
Risk factors for complications include, but are not limited to:
What to Expect TOP
Prior to Procedure
Talk to your doctor about your medicines. You may be asked to stop taking some medicines up to one week before the procedure, like:
Continue to use your eye drops, unless directed otherwise by your doctor.
Arrange for a ride to and from the procedure.
Drops are used to numb the eye for the procedure.
Local anesthesia and sedation may be used for incisional surgery.
General anesthesia is used under some circumstances.
Description of the Procedure TOP
There are two common types of glaucoma surgery: laser and incisional.
The main types of laser surgery include:
Argon Laser Trabeculoplasty (ALT)
Argon laser trabeculoplasty (ALT) is the most common type of laser surgery. It is usually used to treat open angle glaucoma. During this procedure, you will sit facing the laser machine. The laser "spot" will be applied to a special contact lens held on the front of the eye. You may see flashes of red or green light as the laser is applied. This procedure will allow more fluid to be released and relieve some of the pressure.
Selective Laser Trabeculoplasty (SLT)
The procedure is similar to ALT. SLT has the benefit of being repeatable. ALT cannot be done more than twice.
Laser Peripheral Iridotomy (LPI)
Laser peripheral iridotomy (LPI) is frequently used to treat narrow-angle glaucoma or to prevent glaucoma attacks in patients with anatomically narrow angles. Narrow-angle glaucoma occurs when the angle between the cornea (the clear structure on the front of the eye) and the iris (the colored part of the eye) is too small. This can cause the iris to plug up so that fluid cannot flow freely. This can cause the pressure to rise to dangerously high levels very quickly. In LPI, the laser will be used to make a small hole in the iris. The hole will allow fluid to flow more freely within the eye.
Cyclophotocoagulation is used to freeze the parts of the eye that make the eye fluid. This procedure is usually done only in people who have severe damage from glaucoma and for whom other surgeries were not successful. Instead of freezing, this procedure can also be done with a laser.
Incisional Surgery (also known as Filtering Surgery)
This surgery uses tiny instruments to remove a piece from the wall of the eye. This creates a small hole, which is covered by conjunctiva (layer around the eye). The fluid can now drain out through the hole. It will then be reabsorbed into the bloodstream. This reduces the pressure in the eye. In some cases, the doctor may place a valve in the eye through a tiny incision.
If the above methods fail, another option is the use of implants. With implant surgery, most of the device is positioned on the outside of the eye. A small tube or filament is carefully inserted into the front chamber of the eye. The fluid drains through the tube, or along the filament, into the area around the back end of the implant. The fluid collects here and is reabsorbed. This procedure is slightly more risky than standard trabeculoplasty and should only be performed by doctors well versed in the technique.
How Long Will It Take? TOP
The procedure usually takes less than one hour. People having the incisional procedure may need about 4-8 hours from the time of arrival until discharge.
Will It Hurt? TOP
For most people, the local anesthesia will block pain during surgery. There may be some burning or stinging with ALT and LPI. Some people report mild discomfort during the procedures. Incisional glaucoma surgeries tend to have more discomfort after the procedure than laser procedures.
Post-procedure Care TOP
At the Care Center
After the procedure, you may be given:
Be sure to follow your doctor's instructions.
Call Your Doctor TOP
After arriving home, contact your doctor if any of the following occurs:
In case of an emergency, call for medical help right away.
Glaucoma Research Foundation
National Eye Institute
Canadian Association of Optometrists
Canadian Ophthalmological Society
Glaucoma surgery. Glaucoma Research Foundation website. Available at:
...(Click grey area to select URL)
Accessed July 17, 2014.
How glaucoma is treated. The Glaucoma Foundation website. Available at: https://www.glaucomafoundation.org/treating_glaucoma.htm. Accessed July 17, 2014.
Last reviewed June 2014 by Eric Berman, MD
Last Updated: 7/17/2014