Surgery reduces the pressure in the eyes by opening blocked drainage angles or creating a new opening that fluid can flow through to leave the eye. In some cases surgery may be done to relieve pain caused by glaucoma.
Medicine will usually be tried before surgery is considered.
Most of the focusing power in the eye occurs along the front surface, called the cornea, which is the clear "window" in the front of the eyeball. The next structure involved in focussing is the lens, which sits behind the cornea inside the eye. The ideal cornea has a round, symmetrically curved surface, like a basketball. Astigmatism is caused by an "out of round" cornea or a lens that is not symmetrical. As a result, people with significant astigmatism may have distorted or blurry vision.
Doctors can use either a surgical cutting tool or a very focused beam of light, called a laser, to do surgery for glaucoma. Laser surgery is usually the first type of surgery tried. If laser surgery doesn't help, your doctor may try conventional surgery.
It is not unusual for some people to have both open- and closed-angle glaucoma. They may need more than one kind of procedure.
Surgery choices for adults
There are three basic types of surgery for glaucoma in adults.
Surgery to increase drainage of fluid from the eye
This type of surgery involves making a trapdoor that allows fluid to drain from the eye.
Trabeculectomy involves an incision to remove a piece of tissue to allow fluid to drain from the eye.
Tube-shunt surgery (seton glaucoma surgery) involves an incision to place a tube in the eye to allow fluid to drain.
Laser sclerostomy removes a piece of the white part of the eye to allow fluid to drain. This type of surgery is rarely done.
Surgery to prevent closure of the drainage angle
These procedures involve making a new opening in the colored part of the eye (iris) that allows fluid to flow through the eye. They are used to treat sudden (acute) and long-term closed-angle glaucoma. The procedures also will prevent closed-angle glaucoma in people who have narrow drainage angles.
Laser iridotomy can usually be done instead of surgical iridectomy. But some people with complicated or severe glaucoma may need to have surgical iridotomy.
Surgery to decrease the amount of fluid produced in the eye
When other surgery fails to improve the flow of fluid from the eye, procedures to destroy the part of the eye that produces fluid (ciliary body) can be done. These procedures are also used when scar tissue has formed after a previous surgery.