Glaucoma: Frequently Asked Questions

Glaucoma is the name given to a group of eye diseases that lead to damage of the optic nerve (the bundle of nerve fibers that carries information from the eye to the brain), which can then lead to vision loss and possibly blindness. Optic nerve damage usually occurs in the presence of high eye pressure; however, it can occur with normal or even less than normal eye pressure. Read the answers to the most frequently asked question about this eye disease.

More than three million Americans are living with glaucoma, 2.7 million of whom—aged 40 and older—are affected by its most common form, open-angle glaucoma. Some studies have shown that perhaps half of people living with glaucoma aren't even aware they have the disease. In the past, 60.5 million people worldwide were estimated to be living with open-angle and angle-closure glaucoma by 2010. In 2020, about 80 million people have glaucoma worldwide, and this number is expected to increase to over 111 million by 2040.

Because most forms of glaucoma develop slowly and silently, everyone, especially those at high risk, should be sure to have their eyes examined on a regular basis, preferably every one to two years or as directed by a doctor.

What Are Different Forms of Glaucoma?

There are two main forms of glaucoma: open-angle (the most common form, affecting approximately 70-90% of individuals); and angle-closure. There are also several other forms of glaucoma, including normal-tension, congenital, juvenile, and secondary.

Open-angle Glaucoma

This is the most common form of the disease, is progressive and characterized by optic nerve damage. The most significant risk factor for the development and advancement of this form is high eye pressure. Initially, there are usually no symptoms, but as eye pressure gradually builds, at some point the optic nerve is impaired and peripheral vision is lost. Without treatment, an individual can become totally blind.

Angle-closure Glaucoma

Angle-closure glaucoma may be acute or chronic. In acute angle-closure (also called closed angle) glaucoma, the normal flow of eye fluid (aqueous humor) between the iris and the lens is suddenly blocked. Symptoms may include severe pain, nausea, vomiting, blurred vision, and seeing a rainbow halo around lights. Acute angle-closure glaucoma is a medical emergency and must be treated immediately, or blindness could result in one or two days. Chronic angle-closure glaucoma progresses more slowly and can damage the eye without symptoms, similar to open-angle glaucoma.

Normal-tension Glaucoma

Normal-tension glaucoma occurs when eye pressure is normal, yet the optic nerve is damaged and peripheral vision is lost. Lowering eye pressure through medication sometimes slows the progress of the disease, but this type of glaucoma may worsen despite low pressure. The treatment is generally the same as for open-angle glaucoma. 

Congenital Glaucoma

This affects infants born with defects that prevent the normal drainage of fluid from the eye.

Juvenile Glaucoma

Juvenile glaucoma is open-angle glaucoma that affects children, adolescents, and young adults.

Secondary Glaucoma

This can be open-angle or closed-angle and is the result of some other medical condition in the eye or the body.

Who Is At Risk of Developing Glaucoma?

Glaucoma is a leading cause of blindness among African Americans and Hispanics in the U.S. Three times as many African Americans have glaucoma than Caucasians, and four times as many are blind. Between the ages of 45 and 64, glaucoma is fifteen times more likely to cause blindness in African Americans than in Caucasians. All people older than 60 are at a greater risk of developing glaucoma than people who are younger.

Is There a Cure for Glaucoma?

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

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

Normal-tension Glaucoma

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

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

Juvenile Glaucoma

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

Secondary Glaucoma

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.

Can Glaucoma Be Cured by Laser Techniques?

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.

How Is Glaucoma Diagnosed?

Eye doctors use several tests to detect glaucoma:

Tonometry

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

This 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.

What Is Considered Normal Eye Pressure?

Unfortunately, the answer is not any single number. While the average eye pressure is approximately 15, the range of normal eye pressure is much larger. About 90 percent of people will fall between a pressure of 10 and 21. Even so, this does not mean that if you have a pressure of 22 or higher it is abnormal. Every individual and every eye is different. There are many patients with pressures in the mid-20s who do not have glaucoma, and they can be followed with routine eye examinations by their eye care specialist. There are also patients who have been diagnosed with glaucoma and yet, even though treatment may decrease their pressure below 22, they still experience worsening of their glaucoma. 

It is important that you see an eye care specialist to receive a thorough examination and determine if your eye pressure is problematic

How Do Pressure Inside the Eye and Other Factors Effect Vision and Glaucoma?

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.

What Resources Are Available to Help People with Glaucoma and Their Caregivers?

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 handheld 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 plugins; and smartphone applications. One specialized device can take pictures of signs or menus and read the words in the pictures aloud.

Where Can I Find More Information?

The glaucoma section of our website at goes into greater depth on many of the above 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 BrightFocus publications. And explore our Ask an Expert section where you can read or post queries to doctors.

For a list of helpful organizations dealing with the topics below, visit our helpful resources page.