Frequently Asked Questions

Marijuana derivatives taken orally, intravenously, or by smoking lower the eye pressure only briefly. The active ingredient does not cause reduction of eye pressure when administered in an eye drop formulation. The effects of marijuana are brief, lasting only hours, and are thus not suitable for long-term eye pressure control. Because marijuana can also reduce blood pressure briefly, it may be associated with reduced blood supply to the optic nerve, which could adversely affect patients with glaucoma. Thus, medical marijuana is not recommended in the treatment of glaucoma.

There are a great many resources available to people with low vision and their caretakers. For instance, every state has an agency on aging. You may find it in the phone book, online, or with the help of a librarian or friend.

Professional low vision therapists at eye clinics or other organizations can assist you. Let your eye doctor know what kind of limitations you are experiencing due to vision loss. He or she can then refer you to a vision rehabilitation center, where a low vision therapist can work with you to help you adapt and resolve specific problems.

You can also modify your environment, use low vision aids, develop your senses of hearing and touch, and practice using peripheral vision. Your doctor can prescribe optical devices such as magnifiers. Many non-prescription magnifying glasses and devices are also available to assist with reading and other close work, such as sewing or model-building. These devices range from the simple and inexpensive to more expensive high-tech products that can aid in using computers and watching television.

Many styles of magnifiers, including discreet ones, can be found at drug stores, medical supply stores, or may be ordered online or by phone through low vision product catalogs. A hand-held magnifying glass can help with reading medicine bottle labels, mail, price tags in stores, and restaurant menus. Other magnifiers come in the form of eyeglasses or clip onto glasses to free your hands for other activities.

Commonly used household items with large numbers and letters, and others that "talk," are also available. There are many sources for large-print books and audio materials, as well as services that read newspapers and magazines by phone or over the radio.

Electronic reading aids are proliferating, such as: computer programs that magnify the computer screen and/or read screen text out loud; special scanners to carry while shopping that read out prices, sizes, and colors; web browser plug-ins; and smartphone applications. One specialized device can take pictures of signs or menus and read the words in the pictures aloud.

The AHAF National Glaucoma Research website goes into greater depth on many topics and covers additional areas of concern, both medical and social. You can learn where to get help and access to resources, as well as download free publications. And explore our Ask an Expert section where you can read or post queries to doctors. For more information dealing with the topics below, please visit the helpful organizations section of our website.

• Clinical Trials
• Organizations of Eye-care Professionals
• Federal Government Programs and Services
• General Information, Resources and Referrals
• Legal Assistance
• Low Vision Aid Resources
• Low Vision Organizations
• Print and Audio Materials for the Visually Impaired
• Senior Housing
• State and Local Resources

Individuals at high risk for glaucoma should have a dilated-pupil eye examination at least every two years. Eye doctors use several tests to detect glaucoma:

Tonometry measures the pressure inside the eye. Examples of tonometers include:

• The air-puff (noncontact) tonometer, which emits a puff of air. Eye pressure is measured by the eye's resistance to the air.
• The applanation tonometer, which touches the eye's surface after the eye has been numbed and measures the amount of pressure necessary to flatten the cornea. This is the most sensitive tonometer, but a clear, regularly-shaped cornea is needed for it to function properly.
• The electronic indentation method, which measures pressure by directly contacting anesthetized eyes with a digital pen-like instrument.

In pupil dilation, special drops temporarily enlarge the pupil so the doctor can better view the inside of the eye. Various instruments allow the doctor to determine the thickness of the cornea, to view the front and/or the interior of the eye, and to monitor optic nerve changes over time.

Visual field testing measures the entire area seen by the forward-looking eye to document straight-ahead (central) and/or side (peripheral) vision.

A visual acuity test uses an eye chart to measure sight at various distances.

When a patient has glaucoma or is at high risk for developing the disease, physicians may document changes over time in the optic nerve through imaging techniques including stereo optic nerve photographs, scanning laser polarimetry (GDx), confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph or HRT II) and optical coherence tomography (OCT). An eye care professional will determine which method(s) to use.

No, but there are sight-saving treatments. So the sooner a person is diagnosed, the more vision can be preserved.

The most common treatments for glaucoma are eye drops and, rarely, pills. There are a number of different categories of eye drops, but all are used to either decrease the amount of fluid (aqueous humor) in the eye or improve its outward flow. Sometimes doctors will prescribe a combination of eye drops. People using these medications should be aware of their purpose and potential side effects, which should be explained by a medical professional. A doctor can decide which medications are best suited for a patient based on the individual case of glaucoma, medical history, and current medication regimen.

Treatments vary depending on the type of glaucoma. The most common include:

Open-angle glaucoma treatment normally begins with medications, usually eye drops or, rarely, pills that either help eye fluid drain more effectively or cause the eye to produce less fluid. Several forms of laser surgery can also help fluid drain from the eye. Conventional filtration surgeries such as the glaucoma drainage implant are sometimes used to create a new opening for fluid drainage.

Acute angle-closure glaucoma (a medical emergency) is treated with medications and/or laser procedures.

Chronic angle-closure glaucoma is treated with a laser procedure, often in an office or clinic under local anesthesia, and with medications.

Normal-tension glaucoma is currently treated in the same ways as open-angle glaucoma. When this form of the disease is better understood, treatment strategies may be modified.

Congenital glaucoma is usually treated with medications and one of two forms of eye surgery.

Juvenile glaucoma is treated using medications, laser surgery and conventional filtration surgery.

Secondary glaucoma can be open-angle or angle-closure, and acute or chronic. Treatment depends on these factors and whether the underlying condition causing increased eye pressure needs to be addressed.

Elevated eye pressure increases the risk of developing glaucoma; however, the disease can occur in people with normal or even lower-than-normal eye pressure. It is optic nerve damage that can lead to vision loss and possible blindness. In many people, fluid pressure increases inside the eye and damages the optic nerve (the bundle of nerve fibers that carries information from the eye to the brain). In addition, individuals with higher-than-normal eye pressure do not always develop the symptoms of glaucoma.

Since normal-tension glaucoma does not involve high eye pressure, it is diagnosed by observing the optic nerve for any signs of damage. The eye doctor will use an ophthalmoscope to look through the pupil at the shape and color of the optic nerve. In addition, a visual field test can help determine if there is any loss of peripheral vision. The risk factors for developing normal-tension glaucoma include a family history of glaucoma, low eye pressure, and cardiovascular disease. Ongoing research is aimed at determining all of the factors that contribute to the optic nerve damage. For example, scientists believe the optic nerve may be affected by blood flow in the eye. Researchers are also investigating susceptibility and genetic factors.

Laser surgery can aid in controlling the symptoms of glaucoma, but no treatments currently available will cure the disease. Several forms of laser surgery can help fluid drain from the eye or decrease the amount of fluid produced. These techniques support the maintenance of normal eye pressure and minimize the risk of further damage to the optic nerve.