• Home

Home > Medical Reference > Patient Education

• Highlights
• Introduction
• Causes
• Symptoms
• Outlook
• Risk Factors
• Diagnosis
• Treatment
• Medications
• Surgery
• Lifestyle Changes
• Resources
• References

Glaucoma

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of glaucoma.

Treatment

Most treatments for glaucoma aim to reduce ocular pressure and its fluctuations. Early treatment with medications, surgery, or both can nearly always maintain safe pressure of the aqueous humor, thus preventing optic nerve damage and blindness. The choice between surgery and medications and when to start treatment is not always straightforward. For example, with the introduction of beta blockers and newer glaucoma drugs, there has been a decline in surgeries. It is not clear, however, which drugs are more effective than others and if, over time, any will actually prevent surgery. Patients should discuss all issues with their doctors and ophthalmologists.

Decision to Start Treatment

Many people have high IOP but no sign of nerve damage. Over the course of 20 years, only between 10 - 30% of these people will actually develop glaucoma. Nevertheless, once glaucoma has destroyed optic nerve fibers, no known treatment can reverse the damage.

Indeed, studies suggest that in people with glaucoma, even very small differences in pressure may mean the difference between disease progression and stability. An important trial reported that, on average, treating patients when their glaucoma was first detected reduced IOP by 25%. In addition, treatment reduced the risk for progression by 17%. This study confirmed previous findings supporting early treatment for glaucoma. Another study found that treatment with eye drops halved the risk of developing open-angle glaucoma in African Americans who had elevated IOP. Some evidence suggests that early treatment to lower IOP may be beneficial even in patients with normal tension glaucoma.

However, not all individuals with early signs of glaucoma (elevated IOP or normal-tension glaucoma) develop optic nerve damage and serious vision problems. Nor does treatment prevent progression in a large minority of patients. Medications used for glaucoma also can carry significant side effects and risks.

Some experts suggest that treatment is warranted only in people with early signs of glaucoma who have risk factors for progressive disease and vision loss (thinner corneas, larger cup to optic disc ration, older age, and elevated pressure).

Considerations for Drug Treatments

A number of effective drugs are now available for treating glaucoma. The drugs reduce pressure in the eye but all have a number of side effects that affect other parts of the body. Some of these side effects can be quite severe. Many of the drugs used for glaucoma also interact with common medications for other conditions. To compound the difficulties, many patients require multiple drugs. As a result, only about half of patients comply with their treatments.

Experts generally recommend topical drugs first (those that can be used as eye drops or ointments rather than taken by mouth).

• Topical beta blockers are the standard first-line drugs, most commonly timolol (Timoptic). Newer beta blockers include betaxolol (Betoptic), levobunolol (Betagan), carteolol (Ocupress), and metipranolol (OptiPranolol). Timolol has been used for years, and these other drugs are also well tolerated.
• Topical prostaglandins are alternatives if beta blockers fail. They include latanoprost (Xalatan) and unoprostone (Rescula). Of the standard drugs used for glaucoma, these drugs have the greatest effect on lowering IOPs. They also have fewer widespread effects than the beta blockers.
• Topical carbonic anhydrase inhibitors (CAIs) are less effective than standard beta blockers or prostaglandins but have fewer widespread effects than the beta blockers. They may be helpful in certain cases. Topical forms are dorzolamide (Trusopt) and brinzolamide (Azopt). (Oral CAIs are available and more effective, but they have severe side effects and are rarely used for the long term.)
• Alpha2-adrenergics, also called selective alpha adrenergics, are effective but may not be as well tolerated as timolol. They include brimonidine (Alphagan).
• Miotics, which include pilocarpine and others, were the standard drugs before the introduction of topical beta blockers. They have now been largely replaced by timolol and others, although they are sometimes used in combinations.
• Beta blockers and newer drugs (prostaglandins, topical CAIs, and selective alpha adrenergics) are now preferred over the older drugs, which include miotics, oral CAIs, and nonselective alpha adrenergics.

Combinations. Combinations of these drugs can be very effective, because they tend to have different actions. Single medications that contain two drugs are becoming available. For example, Cosopt combines timolol and dorzolamide; Timpilo is a combination of timolol and pilocarpine. Studies of these and other combinations compared to each other to single drugs are ongoing. To date, results on any superior combinations have been mixed. It should be noted that the side effects of each drug apply to any combination.

Treating the Pregnant Patient. Considerations for a pregnant woman with glaucoma can be complicated. All of the drugs used for glaucoma are absorbed by the body, cross the placenta, and are excreted in breast milk. Many have effects that can interfere with or adversely affect pregnancy.

Women should discuss going off medication, particularly during the first trimester, and be monitored during that time for increasing eye pressure. IOP tends to drop during pregnancy, although usually not to a significant degree. In addition, changes in IOP and visual loss vary greatly. Some women experience no IOP change or visual loss during pregnancy, while others may experience an increase in IOP or worsening of visual loss. It is important that your ophthalmologist carefully considers your individual case and discusses with you the risks and benefits of continuing glaucoma medication during pregnancy.

If women need to take medications, they should try to achieve the lowest dose possible. Some drugs have fewer side effects than others. Pregnant women must also be very careful about administering eye drops to allow as little medication as possible to enter the body. When taking eye drops, press your index finger against the corner of the eye near your nose. This helps prevent the eye drop from passing down into the tear duct where it is easily absorbed through the rest of the body. Even this approach, however, does not guarantee complete safety. Women with glaucoma who are planning to become pregnant might want to consider surgery before they conceive.

Considerations for Surgery

The object of standard glaucoma surgery is to reduce pressure in the eye by increasing the outflow of the aqueous fluid. Two methods are commonly used:

• Filtration surgery (trabeculectomy). This uses standard surgical instruments to open a passage in the eye for draining fluid.
• Laser trabeculoplasty. This procedure uses a laser to burn 80 - 100 tiny holes in the drainage area.

Both are effective, but certain patient groups may respond to one more than the other. For example, African Americans may do better with laser surgery while trabeculectomy may be a better choice for Caucasians with no serious medical problems.

In general, surgery is a last resort. Doctors may, however, recommend surgery before drug therapies for patients unlikely to comply with difficult drug regimens or for patients who may have severe reactions from the glaucoma drugs. Women who plan on becoming pregnant should also discuss surgery with their doctor.

Some studies indicate that laser treatment performed as the initial treatment for glaucoma is as effective as medications in some cases. Findings in 2003 from a major comparison study suggested that 4 years after surgery there was little difference in visual field loss between trabeculectomy and medical treatment. There was, however, a higher risk for cataracts and loss of vision sharpness with surgery. On the other hand, side effects from medications may be ongoing and troublesome. It is important to note that even surgery does not cure glaucoma, and over half of patients will require medication within 2 years. Experts who are against early surgeries also argue that studies on their success often omitted serious postoperative problems, such as late-onset infection, and quality of life assessments.

• Review Date: 3/3/2007
• Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.