Surgery

Surgery is not always necessary to treat glaucoma. Medicines can often control the pressure in the eyes, preventing further vision loss and blindness. Medicine will usually be tried first before surgery is considered.

Doctors can use either a surgical cutting tool or a very focused beam of light, called a laser, to perform surgery for glaucoma. Laser surgery is usually tried first when glaucoma medicines do not lower the pressure in the eyes (intraocular pressure, or IOP). If laser surgery does not help, your doctor may try conventional surgery.

Surgery may be needed for:

• Sudden (acute) closed-angle glaucoma. Laser treatment can create an opening in the colored part of the eye (iris) that will let fluid drain from the eye. People who have had closed-angle glaucoma in one eye usually need to have laser treatment on the other eye to prevent the same condition from developing. Also, people who have narrow drainage angles may need laser treatment to prevent acute closed-angle glaucoma. If laser treatment is not successful, then conventional surgery, such as surgical iridectomy or trabeculectomy, would be needed.
• Open-angle glaucoma, if the pressure in the eyes stays high or if damage to the optic nerve continues despite medication. Laser treatment may be needed early on to treat open-angle glaucoma, especially in people who have very high intraocular pressure and severe glaucoma. You may have laser surgery before you try medicine. In some cases, early surgery in open-angle glaucoma may be more effective than eyedrops at reducing the pressure in the eyes and preventing blindness.
• Infants with congenital glaucoma. They may need surgery as soon as possible to prevent blindness.

The primary goal of surgery for glaucoma is to preserve eyesight by:

• Maintaining the health of the optic nerve.
• Reducing the pressure in the eyes by opening blocked drainage angles or creating a new opening that fluid (aqueous humor) can flow through to leave the eye.

In some cases surgery may be done to relieve pain caused by glaucoma.

Surgery Choices

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. The surgeon can use either a laser or a surgical cutting tool to do this. In severe glaucoma, surgery also may involve putting in a filtering device (seton), usually made of plastic, that drains fluid away from the front part of the eye to a place where it can drain out of the eye. These procedures are used to treat open-angle glaucoma and long-term (chronic) closed-angle glaucoma.

• Trabeculectomy removes a piece of tissue to allow fluid to drain from the eye.
• Tube-shunt surgery (seton glaucoma surgery) places 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.

Surgery to prevent closure of the drainage angle

Both laser and conventional surgeries can be used 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) closed-angle glaucoma and 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.

• Surgical iridectomy makes an opening in the iris to allow fluid to drain.
• Laser iridotomy uses a laser to create an opening in the iris for fluid to drain.

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.

Destroying the ciliary body decreases the amount of fluid produced in the eye, reducing the pressure in the eye. Procedures that decrease fluid in the eye are only used for people with severe glaucoma that has not gotten better after they have tried medicines or other forms of surgery.

• Cyclocryotherapy uses a freezing probe to destroy the ciliary body.
• Laser cyclophotocoagulation uses a laser to destroy the ciliary body.

Surgery for congenital glaucoma

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 (seton glaucoma) 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.

What to Think About

Clouding of the lens (cataract) can develop after surgery for glaucoma and is one reason that surgery is not usually used first to treat open-angle glaucoma.

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 surgery for glaucoma and a cataract are done at the same time, you may notice improved eyesight after surgery.

The decision whether or not to have surgery is often more difficult in glaucoma than in many other conditions because:

• In many instances, the person is not in pain and often does not notice any vision loss.
• Surgery often causes a person's eyesight to get worse immediately after surgery. Vision may be affected for weeks or months after surgery. For some people, their eyesight is never as good as it was before the surgery. Surgery is not a complete cure for glaucoma. But surgery can decrease the chance of losing even more eyesight later on.
• Not everyone who has laser surgery will have lower intraocular pressure after the surgery. For some 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 are not 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 factor to consider is which eye should be operated on first. There are other questions about glaucoma surgery that you should discuss with your doctor before making a decision.

Procedures to destroy the structures in the eye that produce fluid (cyclodestructive procedures) are usually used when other treatments, including other surgeries for glaucoma, have failed.⁴ Several treatments over time can destroy too much of the ciliary body, causing too little fluid to be produced. This can cause the eyeball to soften and lead to clouding of the lens (cataract).