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.

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 trabeculoplasty burns tissue to create an opening that allows fluid to drain from the eye.
• 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.

• Surgical iridectomy uses a surgical cutting tool.
• Laser iridotomy uses a laser.

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.

Surgery choices for children

For congenital glaucoma, there are two slightly different procedures that both attempt to open the drainage angle directly. They are equally successful in children, but they are not used for adults. If these procedures fail in a child, then trabeculectomy or tube-shunt surgery may be tried.

• Goniotomy creates an opening in the trabecular meshwork to allow fluid to drain from the eye.
• Trabeculotomy removes a piece of tissue to allow fluid to drain from the eye.

Deciding about surgery

Deciding whether to have surgery is difficult because:

• You may not be in pain or notice any vision loss.
• Your vision may get worse right after surgery and may be affected for weeks or months. Your eyesight may not be as good as it was before the surgery.
• Surgery isn't a complete cure for glaucoma. But surgery can decrease the chance of losing even more eyesight later on. And for some people, it can reduce or get rid of the need for eyedrops.
• Not everyone who has laser surgery will have lower IOP after the surgery. For most people, the lower pressure will last only a few years. Others may have an increase in their eye pressure. Certain types of open-angle glaucoma respond better to laser surgery than others.
• The effects of some laser treatments aren't long-lasting. Repeat laser treatments, medicines, or other surgeries may be needed later on.

As with any other surgery, you and your doctor should make the decision to operate based on the risks and benefits of having the surgery. One thing to consider is which eye should be operated on first. There may be other questions about glaucoma surgery that you should discuss with your doctor before making a decision.

Cataracts may occur in people who also have glaucoma. This commonly occurs in older people. Surgery to remove the cataract may be done at the same time as surgery for glaucoma. If surgeries for glaucoma and a cataract are done at the same time, you may notice improved eyesight after surgery.