Glaucoma Conditions & Procedures

The Basics

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The image on the right shows a healthy optic nerve while the image on the left shows a nerve with glaucoma changes.

Glaucoma is a disease of the optic nerve, which transmits the images you see from the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric cable with its numerous wires). Glaucoma damages nerve fibers, which can cause blind spots and vision loss.

Glaucoma has to do with the pressure inside the eye, known as intraocular pressure (IOP). When the aqueous humor (a clear liquid that normally flows in and out of the eye) cannot drain properly, pressure builds up in the eye. The resulting increase in IOP can damage the optic nerve and lead to vision loss.

The most common form of glaucoma is primary open-angle glaucoma, in which the aqueous fluid is blocked from flowing back out of the eye at a normal rate through a tiny drainage system. Most people who develop primary open-angle glaucoma notice no symptoms until their vision is impaired.

Ocular hypertension is often a forerunner to actual open-angle glaucoma. When ocular pressure is above normal, the risk of developing glaucoma increases. Several risk factors will affect whether you will develop glaucoma, including the level of IOP, family history, and corneal thickness. If your risk is high, your ophthalmologist (Eye M.D.) may recommend treatment to lower your IOP to prevent future damage.

Angle-closure Glaucoma

glucoma

The left blue arrow shows how fluid pushes the iris forward, blocking the normal route through which the fluid leaves the eye. This is called angle-closure glaucoma and results in high intraocular pressure. The right side shows how a small hole in the iris (peripheral iridotomy) created by a laser restores the normal flow of fluid, thereby lowering the pressure in the eye.

In angle-closure glaucoma, the iris (the colored part of the eye) may drop over and completely close off the drainage angle, abruptly blocking the flow of aqueous fluid and leading to increased IOP or optic nerve damage. In acute angle-closure glaucoma there is a sudden increase in IOP due to the buildup of aqueous fluid. This condition is considered an emergency because optic nerve damage and vision loss can occur within hours of the problem. Symptoms can include nausea, vomiting, seeing halos around lights, and eye pain.

Even some people with "normal" IOP can experience vision loss from glaucoma. This condition is called normal-tension glaucoma. In this type of glaucoma, the optic nerve is damaged even though the IOP is considered normal. Normal-tension glaucoma is not well understood, but lowering IOP has been shown to slow progression of this form of glaucoma.

Your ophthalmologist may tell you that you are at risk for glaucoma if you have one or more risk factors, including having an elevated IOP, a family history of glaucoma, certain optic nerve conditions, are of a particular ethnic background, or are of advanced age. Regular examinations with your ophthalmologist are important if you are at risk for this condition.

The goal of glaucoma treatment is to lower your eye pressure to prevent or slow further vision loss. Your ophthalmologist will recommend treatment if the risk of vision loss is high. Treatment often consists of eyedrops but can include laser treatment or surgery to create a new drain in the eye. Glaucoma is a chronic disease that can be controlled but not cured. Ongoing monitoring (every three to six months) is needed to watch for changes. Ask your ophthalmologist if you have any questions about glaucoma or your treatment.

Normal-Tension Glaucoma

Normal-Tension Glaucoma

Normal-tension glaucoma typically means that glaucoma damage has been detected in an eye with so-called "normal" intraocular pressure (IOP) — that is, an eye that has not had documented pressure above 20 mm Hg. Ophthalmologists increasingly believe that this condition is a continuum of the same glaucoma process seen in those people with higher IOP.

Normal-tension glaucoma is diagnosed by examining the appearance of the optic nerve or by detecting abnormalities on visual field tests.

One large study showed that progressive damage and visual field loss can be significantly reduced in people with normal-tension glaucoma by lowering their IOP by 30% or more.

Other conditions can sometimes be mistaken for normal-tension glaucoma, so thorough eye and medical examinations are often required to make this diagnosis. Often the IOP will be measured at different times during the day to see if there are any pressure elevations. Other tests may also be necessary.

If your ophthalmologist (Eye M.D.) believes that you have normal-tension glaucoma, he or she may begin treatments to lower your IOP. This can be done with medications, laser treatment, or surgery.

Patients with adequately treated normal-tension glaucoma have a good prognosis, especially when the disease is caught early in its course.

Steroid Glaucoma

Steroid or glucocorticoid medications are used to treat a variety of medical conditions. They can be administered by mouth, nasal sprays or inhalers, eyedrops, or injections. No matter how the medication is taken, up to 20% of patients taking steroid medications develop elevated intraocular pressure (IOP).

If eye pressure does become elevated, sometimes the steroid medicine can be stopped or decreased, helping to alleviate the problem. If the steroid medication was given by injection in or around the eye, the eye pressure may be harder to control.

If medical therapy does not adequately lower IOP, surgery may be required. As with other forms of glaucoma, if IOP can be controlled, patients tend to do well.

Traumatic Glaucoma

If your eye is injured, there is a chance you will develop traumatic glaucoma. A direct blow to the eye can cause bleeding or inflammation in the eye, which may lead to an acute rise in eye pressure. This condition can typically be managed with eyedrop medication. However, if the intraocular pressure (IOP) is very high or if blood remains in the eye, surgical treatment may be required.

If an eye is hit hard enough to cause bleeding in the front part of the eye, this is called a hyphema. A hyphema increases the possibility of a rise in IOP. Various medications can bring the pressure down to a safe zone until the blood decreases or disappears.

In cases of a hyphema, there is also a chance of a future increase in IOP. The chance of developing elevated IOP and glaucoma following a hyphema is thought to be approximately 8% over a patient's lifetime. Therefore, anyone who has had eye trauma should be sure to have intraocular pressure checks every year. If your ophthalmologist (Eye M.D.) notes an increase in your eye pressure, he or she can find ways to control it.

Neovascular Glaucoma

Neovascular Glaucoma

Neovascular glaucoma is a particularly aggressive and difficult to treat kind of glaucoma. It is caused by new, small blood vessels growing in the front part of the eye. These neovascularvessels grow on the surface of the iris (the colored part of the eye) and over the drainage channel, blocking the flow of fluid from the eye. This causes a rapid and painful rise in pressure within the eye. This type of glaucoma often does not respond well to medical treatment, and the high intraocular pressure can lead to a rapid loss of vision.

Causes of neovascular glaucoma include diabetic retinopathy, vein and artery occlusions, carotid artery disease, and many other conditions. The prognosis for neovascular glaucoma is poor. The goal of treatment is to minimize the factors that have caused the neovascularization, usually using a laser treatment called panretinal photocoagulation or anti-VEGF injections.

If the high eye pressure persists, treatment can include medication or surgery. When surgery is recommended, a particular type of medication therapy called antimetabolite therapy improves the chances of success. Because of the risk of scarring, seton surgery is often recommended.

The goal in treating neovascular glaucoma is to lower the intraocular pressure, preserve vision, and maintain a comfortable eye.

Pigmentary Glaucoma

Pigmentary Glaucoma
Pigmentary dispersion syndrome is a condition in which increased amounts of pigment circulate within the front portion of the eye. This often results in having pigment layered on the back of the cornea, thinning of the iris, and clogging of the ocular drainage system with pigment. This pigment can block the drainage channel enough to cause an increase in intraocular pressure (IOP).

In cases of pigmentary glaucoma, the IOP often is very high, reaching levels above 40 mm Hg. Pigmentary dispersion leads to damage from glaucoma in 20% to 50% of patients. It is more common in males and often appears in people under 50 years of age.

Treatment is the same as for other forms of open-angle glaucoma, including medications, laser therapy, or surgery. With adequate treatment, the prognosis for pigmentary glaucoma is good.

Pseudoexfoliation Glaucoma

Pseudoexfoliation glaucoma is a relatively common form of open-angle glaucoma that can cause significantly high eye pressures. This condition is marked by a dust-like material that is observed inside the eye on the surface of the iris and lens. This material can clog the ocular drainage system, increasing intraocular pressure (IOP). It can occur in one or both eyes and is most commonly seen in patients over the age of 70. Pseudoexfoliation glaucoma is found in all ethnic groups, but it is most commonly seen in people of Scandinavian ancestry.

Treatment is often required for pseudoexfoliation glaucoma, consisting of medication, laser treatment, or surgery. Pseudoexfoliation can cause increased complications with cataract surgery. With proper treatment and monitoring, patients with pseudoexfoliation glaucoma tend to do well. Early diagnosis is important.

Nerve-Fiber-Layer Analysis

Early in the disease process of glaucoma, individual nerve fibers in the eye's optic nerve are lost, causing an associated pattern of nerve-fiber-layer thinning. This problem can later translate into loss of tissue at the optic nerve head, resulting in visual field defects and, ultimately, loss of vision.

New techniques have been devised to help measure the thickness of the nerve fiber layer, helping ophthalmologists (Eye M.D.s) diagnose glaucoma earlier and monitor progression of the disease.

One technique used to measure the nerve fiber layer is called scanning laser polarimetry, which utilizes a device called a GDx scanner. Another technique uses a low-power laser light and a process called optical coherence tomography (OCT). These new imaging techniques can help provide an objective measurement of the nerve fiber layer, enhancing the ability to effectively diagnose and monitor glaucoma.

Both tests are done in the ophthalmologist's office. During these tests, the patient is required only to remain still while the image is scanned.

Gonioscopy

Gonioscopy

Because it has no noticeable symptoms, glaucoma is a difficult disease to detect without regular, complete eye exams.

During a glaucoma evaluation, your ophthalmologist (Eye M.D.) will perform a gonioscopy, inspecting your eye's drainage channel.

During gonioscopy, your ophthalmologist will ask you to sit in a chair facing the microscope (slit lamp) used to look inside your eye. You will place your chin on a chin rest and your forehead against a support bar while looking straight ahead. After your eye has been numbed with eyedrops, your ophthalmologist gently places the goniolens on the front of your eye and directs a narrow beam of light into your eye while looking through the slit lamp to examine the drainage angle.

Determining if the drainage angle of the eye is closed or nearly closed helps your ophthalmologist determine which type of glaucoma you have. Gonioscopy can also detect scarring or other damage to the drainage angle that may explain the cause of certain types of glaucoma.

If your ophthalmologist finds that the drainage angle is closed, a special laser can make a small opening in the iris to open the angle. Laser treatment to open the drainage angle may decrease the pressure in the eye and help control glaucoma.

Visual Field Testing

Visual Field Testing

Because it has no noticeable symptoms, glaucoma is a difficult disease to detect without regular, complete eye exams.

One particular test, called a visual field test (orperimetry test), measures all areas of your eyesight, including your side, or peripheral, vision. A visual field test can help find certain patterns of vision loss and is a key way to check for glaucoma. It is very useful in finding early changes in vision caused by nerve damage from glaucoma.

To take this painless test, you sit at a bowl-shaped instrument called a perimeter. While you stare at the center of the bowl, lights flash. Each time you see a flash you press a button. A computer records the location of each flash and whether you pressed the button when the light flashed in that location. At the end of the test, a printout shows if there are areas of your field of vision where you did not see the flashes of light. This test shows if you have any areas of vision loss. Loss of peripheral vision is often an early sign of glaucoma. Regular perimetry tests are an important technique for learning how, if at all, your vision is changing over time. It can also be used to see if treatment for glaucoma is preventing further vision loss.

Trabeculectomy

Trabeculectomy

Conventional surgery to treat glaucoma makes a new opening in the meshwork. This new opening helps fluid to leave the eye and lowers intraocular pressure.

Credit: National Eye Institute, National Institutes of Health

If you have glaucoma and medications and laser surgeries do not lower your eye pressure adequately, your ophthalmologist (Eye M.D.) may recommend a procedure called a trabeculectomy.

In this procedure, a tiny drainage hole is made in the sclera (the white part of the eye). The new drainage hole allows fluid to flow out of the eye into a filtering area called a bleb. The bleb is mostly hidden under the eyelid. When successful, the procedure will lower your intraocular pressure (IOP), minimizing the risk of vision loss from glaucoma. The surgery is performed in an operating room on an outpatient basis.

Some of the risks and complications from trabeculectomy surgery include the following:

  • failure to control intraocular pressure, with the need for another operation;
  • infection;
  • bleeding in the eye;
  • swelling in the eye;
  • irritation or discomfort in the eye;
  • eye pressure that is too low;
  • cataract (in cases where cataract has not already been removed); and
  • decreased or lost vision.

Antimetabolites

Antimetabolites

Certain medications, called antimetabolites, were originally developed to help treat some kinds of cancer. These same medications have also been found to be helpful when used with some types of glaucoma surgery.

These medicines may be applied to the eye during or after the surgery to reduce the growth of scar tissue, a common cause of failure in glaucoma surgery. Mitomycin-C and 5-fluorouracil (5-FU) are the most commonly used antimetabolites for glaucoma surgery. When these antimetabolites are used with other medications that reduce inflammation, the success rate of surgery is greatly improved, especially for patients who are at high risk for excessive scarring.

Your ophthalmologist may consider using antimetabolite medicines with your glaucoma surgery if:

  • you are having surgery on an eye that has been operated on before;
  • you have inflammation in your eye (called uveitis);
  • you have glaucoma due to new blood vessel formation within the eye;
  • you are having glaucoma and cataract surgery at the same time;
  • you are relatively young;
  • you have more deeply pigmented skin; or
  • your eyes are at risk for postoperative scarring.

In addition to the usual complications of glaucoma surgery, other risks associated with using antimetabolites include:

  • eye pressure that is too low;
  • leaking incisions;
  • slower healing of the cornea;
  • blurred vision;
  • fluid in or behind the retina;
  • thinning of the eye tissues; and
  • infection.

If your ophthalmologist has decided to use antimetabolite medications, he or she will explain why they are recommended for you.

While some people may experience side effects from medications or surgery, the risks associated with these side effects should be balanced against the greater risk of leaving glaucoma untreated and losing your vision.

Bleb Care After Trabeculectomy

Bleb Care After Trabeculectomy

Trabeculectomy surgery for glaucoma results in the creation of a drainage "bubble" under the upper eyelid. Aqueous fluid flows from the eye into this bubble, which is called a bleb. The aqueous fluid is absorbed into tiny blood vessels, keeping eye pressure low.

The bleb tissue is fragile, and it is important to take care of it to maintain proper functioning. Patients should avoid rubbing the bleb; direct contact with this area should be avoided. Patients should wear protective eyewear when engaging in sporting activities.

A bleb that functions well is often thin and is susceptible to infection. If there is any sign of redness or drainage, call your ophthalmologist (Eye M.D.) immediately. An infected bleb can lead to pain, decreased vision, and potentially even loss of vision. Patients who have had anti-scarring medication, such as 5-fluorouracil (5-FU) or mitomycin C, are even more prone to infection. Your ophthalmologist will tell you if this is the case for you.

Another complication that can occur either early or late is a bleb leak. If you detect any abnormal tearing or a change in visual acuity, you need to have your eye examined by your ophthalmologist as soon as possible.

A well-functioning trabeculectomy bleb can last a lifetime. Proper care and maintenance can help ensure that the bleb continues to control your eye pressure.

Seton Surgery for Treating Glaucoma

Seton Surgery for Treating Glaucoma
The purpose of glaucoma drainage surgery is to help control the pressure in your eye and preserve your vision. If the intraocular pressure (IOP) remains too high, your optic nerve becomes damaged, leading to vision loss and eventual blindness.

In cases of severe open-angle glaucoma or chronic (long-term) glaucoma, if your eye is at high risk for scarring and your IOP needs to be lowered to preserve your vision, your ophthalmologist (Eye M.D.) may recommend placing a tiny drainage tube in your eye called a seton.

The drainage tube creates a new channel for fluid to flow from the eye to a filtering area, called a bleb. A tiny plate placed on the eye helps the bleb form and remain open. The tube is covered with a patch and is typically not seen or felt. This procedure is performed in the operating room on an outpatient basis.

When successful, seton surgery will decrease the pressure in your eye, minimizing the risk of vision loss from glaucoma.

Some of the complications of seton surgery may include:

  • failure to control eye pressure with the need for repeat surgery;
  • eye pressure that is too low;
  • irritation or discomfort;
  • double vision;
  • infection;
  • bleeding;
  • cataract; and
  • erosion of the tube, requiring repeat surgery.

While some people may experience side effects from glaucoma medications or surgery, the risks associated with these side effects should be balanced against the greater risk of leaving glaucoma untreated and losing your vision.

Selective Laser Trabeculoplasty

Selective Laser Trabeculoplasty

Selective laser trabeculoplasty (SLT) is a laser surgical procedure used to help lower intraocular pressure (IOP) of patients with open-angle glaucoma. SLT is used to treat the eye's drainage system, known as the trabecular meshwork — the mesh-like drainage canals that surround the iris. Treating this area of the eye's natural drainage system improves the flow of fluid out of the eye, helping to lower the pressure.

The laser used in SLT works at very low levels. It treats specific cells selectively, leaving untreated portions of the trabecular meshwork intact. For this reason, SLT, unlike other types of laser surgery, may be safely repeated many times.

SLT is typically performed in the ophthalmologist's (Eye M.D.'s) office or an outpatient surgery center. The procedure usually takes about five to ten minutes. First, anesthetic drops are placed in your eye. The laser machine looks similar to the examination microscope that your ophthalmologist uses to look at your eyes at each office visit.

You will experience a flash of light with each laser application. Most people are comfortable and do not experience any significant pain during the surgery, although some may feel a little pressure in the eye during the procedure.

Most people will need to have their pressure checked after the laser treatment, since there is a risk of increasing IOP after the procedure. If this does occur, you may require medications to lower the pressure, which will be administered in the office. Rarely, the pressure in the eye increases to a high level and does not come down. If this happens, you may require a surgery in the operating room to lower the pressure.

Most people notice some blurring of their vision after the laser treatment. This typically clears within a few hours. The chance of your vision becoming permanently affected from this laser procedure is very small.

Most patients can resume normal daily activities the day after laser surgery. You may need to use eyedrops after the procedure to help the eye heal properly.

Risks associated with SLT include:

  • increased pressure in the eye, possibly requiring medication or surgery;
  • inflammation in the eye;
  • bleeding;
  • damage to the cornea, iris, or retina from the laser light;
  • failure to adequately lower the eye pressure; and
  • need for repeat laser surgery.

It will take several weeks to determine how much SLT will lower your eye pressure. You may require additional laser or glaucoma drainage surgery to lower the pressure if it is not sufficiently lower after the first laser treatment.

Most patients must continue to take medication in order to control and maintain their IOP; however, surgery can lessen the amount of medication needed.

While some people may experience side effects from medications or surgery, the risks associated with these side effects should be balanced against the greater risk of leaving glaucoma untreated and losing your vision.

Peripheral Iridotomy

Peripheral Iridotomy

The right blue arrow shows the restored flow of fluid after a peripheral iridotomy.

If your ophthalmologist (Eye M.D.) suspects that you have "narrow" or "closed" angles, this means that the drainage channel of your eye is blocked or nearly blocked, placing you at high risk for elevated intraocular pressure and vision loss. This is called angle-closure glaucoma.

An acute attack of angle-closure glaucoma is marked by very high eye pressure and complete blockage of the drainage channel in the eye. Symptoms include pain, red eye, and decreased vision.

To treat angle-closure glaucoma, your ophthalmologist will perform a peripheral iridotomy (PI), creating a surgical opening within the upper part of the iris (the colored part of the eye) using a laser. This opening is typically so small that it cannot be seen with the naked eye. The opening in the iris allows fluid to flow from behind the iris through the opening, allowing the iris to fall back into a more normal position and opening the drain.

This laser treatment is always performed on an outpatient basis, often in the ophthalmologist's office. The treatment will not improve your vision, but it can help prevent vision loss from a dangerous type of glaucoma. The side effects of the treatment can include the appearance of a "light streak," a temporary rise in intraocular pressure, and inflammation.

Argon Laser Trabeculoplasty

Argon Laser Trabeculoplasty

Argon laser trabeculoplasty (ALT) is a laser surgical procedure used for patients with open-angle glaucoma to help lower intraocular pressure (IOP). ALT is used to treat the trabecular meshwork — the mesh-like drainage canals surrounding the iris — that serves as the eye's drainage system. The goal of treatment with ALT is to improve the flow of fluid out of the eye, helping to lower IOP.

Argon laser trabeculoplasty (ALT) is a laser surgical procedure used for patients with open-angle glaucoma to help lower intraocular pressure (IOP). ALT is used to treat the trabecular meshwork — the mesh-like drainage canals surrounding the iris — that serves as the eye's drainage system. The goal of treatment with ALT is to improve the flow of fluid out of the eye, helping to lower IOP.

ALT is typically performed in the ophthalmologist's (Eye M.D.'s) office or an outpatient surgery center. The procedure usually takes about five to ten minutes. First, anesthetic drops are placed in your eye. The laser device looks similar to the examination microscope that your ophthalmologist uses to look at your eyes at each office visit.

You will experience a flash of light with each laser application. Most people are comfortable and do not experience any significant pain during the surgery, though some may feel a little pressure in their eye during the laser procedure.

Most patients will need to have their pressure checked after the laser treatment, since there is a risk of increased eye pressure after the procedure. If this does occur, you may require medications to lower the pressure, which will be administered in the office. Rarely, IOP elevates to a very high pressure and does not come down. If this happens, you may need to have surgery to lower the pressure.

Most people notice some blurring of their vision after the laser treatment. This typically clears within a few hours. The chance of your vision becoming permanently affected from this procedure is very small.

In general, patients can resume normal daily activities the day after laser surgery. You may need to use drops after the laser surgery to help the eye heal properly.

Risks associated with ALT include

  • increased pressure in the eye, possibly requiring medication or surgery to lower it;
  • inflammation in the eye;
  • bleeding;
  • damage to the cornea, iris, or retina from the laser light;
  • failure to adequately lower the eye pressure; and
  • need for repeat laser surgery.

It will take several weeks to determine how much your pressure will be lowered with ALT. You may require additional laser or glaucoma drainage surgery to lower the IOP if it is not sufficiently lowered after the first laser treatment.

In most cases, medications are still necessary to control and maintain eye pressure. However, surgery may lessen the amount of medication you need.

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