What is glaucoma?

Glaucoma is the name given to a group of eye conditions that damage the optic nerve, which is the pathway between the eye and the brain. If left untreated, glaucoma leads to permanent vision loss and blindness. With early detection and treatment, however, you can often protect your eyes from serious vision loss. A diagnosis of glaucoma signals the beginning of an important, long-term partnership with your eye doctor. Carefully following your eye doctor's instructions will help preserve your vision.

What causes glaucoma?

Although an exact cause is unknown, glaucoma is most often associated with abnormally high pressure inside the eye. This pressure— called intraocular pressure or IOP—comes from a buildup of aqueous humor, which is the clear fluid that is produced continuously inside your eye. Usually, this fluid exits your eye through a drainage system at the angle where the iris (the colored part of the eye) and the cornea (the clear covering of the eye) meet (see How Eye Pressure Builds up). If the drainage system does not work properly, the pressure within the eye increases and damages the optic nerve.

What are the symptoms of glaucoma?

Glaucoma has been called the “silent thief of sight,” because the most common type, primary open-angle glaucoma, has no symptoms until it reaches an advanced stage when vision loss becomes apparent. Without treatment, people with glaucoma slowly lose their peripheral (side) vision until they seem to be looking through a tunnel. Over time, central vision may worsen until no vision remains. Anyone with risk factors for glaucoma should have regular comprehensive eye examinations by an eye care professional.

What are the risk factors for glaucoma?

Everyone is at risk for glaucoma, but some factors can increase your risk, such as:

  • High eye pressure—Only an eye doctor can detect this during a comprehensive eye examination.
  • Age—The older you are, the greater your risk for glaucoma is.
  • Race—People of African descent have a higher risk for open-angle glaucoma than people of other races, and they are also more likely to have glaucoma at a younger age. People of Hispanic ancestry who are over the age of 60 also have a higher risk of open-angle glaucoma. People of Asian descent appear to be at increased risk for angle-closure glaucoma, and those of Japanese descent are at higher risk for normal-tension glaucoma. For more on the types of glaucoma, see page 4.
  • Family history of glaucoma. Primary openangle glaucoma is an inherited condition. If members of your immediate family have glaucoma, you are at a much higher risk than the rest of the population.

Some medical conditions, such as high blood pressure, poorly controlled diabetes, and underactive thyroid (hypothyroidism), may be associated with what is called secondary glaucoma. Steroid drugs used to treat eye inflammations and other diseases can trigger secondary glaucoma in some people.

Are there special tests for glaucoma?

Your eye doctor can detect glaucoma during a comprehensive dilated eye examination. During the examination, the doctor places drops in your eyes to widen (dilate) your pupils and then uses a special light and magnifying lens to examine the back of your eye and the optic nerve. (Your near vision may remain blurred for several hours after the examination because of the drops.) Other diagnostic tests include:

  • Eye pressure (tonometry). To take this reading, your eye doctor numbs your eyes with drops, then briefly touches the tonometer to the surface of each eye to measure the pressure. Another type of tonometer releases a warm puff of air on the eye's surface, which also provides a pressure reading. Normal eye pressure ranges from 12 to 22 millimeters of mercury (mm Hg). Each person's pressure is unique and may change throughout the day.
  • Visual field (perimetry). This test measures your peripheral vision. You sit in front of a bowlshaped machine and stare at a central spot while tiny flashes of light randomly appear around the inside of the bowl. You press a button whenever you see a light. A computer records the spots where the flashes occurred, and a printout shows if you did not see any flashes.
  • Gonioscopy. This test helps determine if the angle where the iris meets the cornea is open or closed. After numbing your eye with drops, your doctor gently places a hand-held lens on the eye. This lens has a mirror that shows the angle. A closed angle is a possible sign of angle-closure or acute glaucoma. If you have other signs of glaucoma, an open angle could indicate chronic, open-angle glaucoma.
  • Gonioscopy. This test helps determine if the angle where the iris meets the cornea is open or closed. After numbing your eye with drops, your doctor gently places a hand-held lens on the eye. This lens has a mirror that shows the angle. A closed angle is a possible sign of angle-closure or acute glaucoma. If you have other signs of glaucoma, an open angle could indicate chronic, open-angle glaucoma.
  • Corneal thickness (pachymetry). Your doctor will want to know the thickness of your cornea because an unusually thin or thick cornea can affect the accuracy of eye pressure readings. These are the most common tests used when glaucoma is suspected, but your eye doctor may use other instruments and tests to obtain as much information as possible before he or she reaches a final diagnosis and decides on a treatment plan.

Do people with high eye pressure always develop glaucoma?

Not always. Some people can tolerate higher-thanaverage eye pressures, and what is a high pressure for one person may be normal for someone else.

I have normal eye pressure. Does that mean I cannot get glaucoma?

People with normal eye pressures can develop a form of open-angle glaucoma called low-tension or normal-tension glaucoma.

Is there a cure for glaucoma?

Unfortunately, glaucoma cannot be cured or prevented, and vision lost because of glaucoma cannot be restored. Lowering eye pressure in the early stages of glaucoma may slow its progression and helps save vision. Depending on the type of glaucoma and if it is mild, moderate, or advanced, treatment may involve prescription medications— usually eye drops—or surgery or both.

How is glaucoma treated with eye drops?

The main goal of eye drops is to lower eye pressure. If your doctor prescribes eye drops for glaucoma, be sure to use them every day as prescribed.

Do glaucoma drops have side effects?

Most people have no serious problems with eye drops for glaucoma, but some drops can cause headaches or other side effects, such as red eyes or temporary burning or stinging. Many different types of eye drops are available to treat high eye pressure, so if you have problems with one medicine, your eye doctor may prescribe something else.

How long must I use eye drops for glaucoma?

Glaucoma is a chronic, incurable condition, so people with glaucoma must use their drops as long as they help control their eye pressure, sometimes for the rest of their lives. Because glaucoma has no symptoms, some people are tempted to stop using their drops, or they may forget to use them. This gives glaucoma a chance to get worse. Using your drops as prescribed is very important to control eye pressure and help prevent vision loss.

What if my glaucoma continues to progress?

If your high intraocular pressure cannot be controlled with medication, your doctor may recommend surgery.

How can surgery help glaucoma?

Surgery cannot reverse vision loss, but it can help lower eye pressure by improving the flow of fluid out of the eye when medication is not sufficient. Surgery may involve laser treatment, an incisional procedure called filtration surgery, or the insertion of a drainage tube. All of these methods are used to reduce intraocular pressure. The type of surgery your doctor recommends will depend on the type and severity of your glaucoma and the general health of your eye.

What are the most common laser surgeries to treat glaucoma?

The most common laser surgeries to treat primary open-angle glaucoma are argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). During ALT, a laser beam opens the fluid channels of the eye, helping the drainage system work better. SLT uses a laser that works at very low energy levels and selectively treats specific cells, while leaving untreated areas intact.

Even when laser trabeculoplasty is successful, most patients need to continue using eye drops to control and maintain normal eye pressures. Surgery may lessen the amount of medication needed.

People with angle-closure glaucoma or those who have very narrow drainage angles may have a procedure called laser iridotomy. During this procedure, the eye surgeon uses a laser to create a small hole about the size of a pinhead through the top of the iris to improve the flow of the fluid inside the eye to the drainage angle.

What does filtration surgery involve?

Filtration surgery, called trabeculectomy, is an outpatient procedure, which is generally indicated after failed medical therapy and laser surgery. It is usually performed using a local anesthetic and relaxing medications. An eye surgeon makes a small flap in the white part of the eye (sclera) and creates a reservoir, called a bleb, under the clear membrane (conjunctiva) that covers the sclera. The bleb looks like a bump or blister on the sclera. The aqueous humor drains through the flap and collects in the bleb, where it is absorbed into blood vessels around the eye.

Immediately after surgery, the operated eye will be red and irritated, and there may be increased tears. Generally, you should avoid getting water in the operated eye for 1 week and avoid driving, reading, bending, and heavy lifting. Every patient is different, however, so it's important to follow your surgeon's specific instructions.

What is recovery like after filtration surgery?

Recovery from trabeculectomy can take up to 8 weeks. During this time, vision will be blurry, and your surgeon will want to see you frequently, usually on a weekly basis, to check eye pressure and make adjustments to the flap to ensure that your eye pressure is not too high or too low. If the pressure remains too high, your doctor may prescribe IOP-lowering drops.

Are there complications with filtration surgery?

Trabeculectomy has been used safely to help control eye pressure for more than 40 years. As with any surgery, however, there may be complications. Some complications of trabeculectomy include lower-than-normal eye pressure, bleb leaks or failure (scar tissue grows over the opening), and, rarely, bleeding or infection.

My surgeon will use a drainage device for my trabeculectomy. What is that?

Many surgeons now implant an artificial drainage device instead of creating a hole. One such device is the EX-PRESS® Glaucoma Filtration Device (Alcon Laboratories Inc.). The EX-PRESS® Glaucoma Filtration Device is intended to reduce intraocular pressure in glaucoma patients where medical and conventional surgical treatments have failed. A filtration device has several advantages over traditional trabeculectomy:

  • Less invasive. No tissue is removed.
  • More precise. Fluid outflow is controlled by the exact size of the opening of the device and the scleral flap.
  • Fewer complications. Researchers have found that a majority of patients who receive the EX-PRESS® device have fewer postoperative complications and need fewer glaucoma medications and glaucoma surgeries after receiving the implant than patients who have traditional trabeculectomy.
  • Quicker recovery. Researchers have also found that patients who receive the EX-PRESS® device have a faster visual recovery and need fewer postoperative eye doctor visits than those who have traditional trabeculectomy.1-4

Although the EX-PRESS® Glaucoma Filtration Device has been shown to reduce complications in filtration surgery when compared to trabeculectomy, as with any surgery, there are risks. Some potential device-related complications include obstruction, malfunction, extrusion, or erosion. In addition, any type of filtering surgery, including trabeculectomy or the implantation of the EX-PRESS® Glaucoma Filtration Device, carries the risk of hyphema, hypotony, choroidal effusion, or choroidal detachment. You should speak with your eye doctor about the potential benefits and risks of using the EX-PRESS® Glaucoma Filtration Device.

Is there a treatment for people whose filtration surgery has failed?

People who have certain types of glaucoma, uncontrolled glaucoma, or failed filtration surgery may undergo what is called tube-shunt surgery. There are several types of glaucoma tubes or shunts, but the surgery is similar regardless of the device used. The surgeon makes a small incision near the top of eye under the conjunctiva, inserts the body of the device, and sutures it in place. A drainage tube, which extends from the body of the device, is inserted into the front part of the eye.

  1. Dahan E, Ben Simon GJ, Lafuna A. Comparison of trabeculectomy and Ex-Press implantation in fellow eyes of the same patient: a prospective, randomised study. Eye (Lond). 2012;26:703-710.
  2. de Jong L, Lafuma A, Aguadé AS, Berdeaux G. Five-year extension of a clinical trial comparing the Ex-Press glaucoma filtration device and trabeculectomy in primary open-angle glaucoma. Clin Ophthalmol. 2011;5:527-533.
  3. Good TJ, Kahook MY. Assessment of bleb morphologic features and postoperative outcomes after Ex-PRESS drainage device implantation versus trabeculectomy. Am J Ophthalmol. 2011;151:507-513.
  4. Maris PJ Jr, Ishida K, Netland PA. Comparison of trabeculectomy with Ex-Press miniature glaucoma device implanted under scleral flap. J Glaucoma. 2007;16:14-19.
  5. Burdon KP, Crawford A, Casson RJ, et al. Glaucoma risk alleles at CDKN2B-AS1 are associated with lower intraocular pressure, normal-tension glaucoma, and advanced glaucoma. Ophthalmology. 2012;119:1539- 1545.