Glaucoma is a group of eye diseases causing optic nerve damage. The optic nerve carries images from the retina, which is the specialized light sensing tissue, to the brain so we can see. In glaucoma, eye pressure plays a role in damaging the delicate nerve fibers of the optic nerve. When a significant number of nerve fibers are damaged, blind spots develop in the field of vision. Once nerve damage and visual loss occur, it is permanent. Most people don't notice these blind areas until much of the optic nerve damage has already occurred. If the entire nerve is destroyed, blindness results. Glaucoma is a leading cause of blindness in the world, especially in older people. Early detection and treatment by your ophthalmologist are the keys to preventing optic nerve damage and vision loss from glaucoma.
The exact causes of optic nerve damage from glaucoma is not fully understood, but involves mechanical compression and/or decreased blood flow of the optic nerve. Although high eye pressure sometimes leads to glaucoma, many people can also develop glaucoma with "normal" eye pressure.
- Open-angle glaucoma
- Chronic open-angle glaucoma is the most common form of glaucoma. The "open" drainage angle of the eye can become blocked leading to gradual increased eye pressure. If this increased pressure results in optic nerve damage, it is known as chronic open-angle glaucoma. The optic nerve damage and vision loss usually occurs so gradually and painlessly that you are not aware of trouble until the optic nerve is already badly damaged.
- Angle-closure glaucoma
- Angle-closure glaucoma results when the drainage angle of the eye narrows and becomes completely blocked. In the eye, the iris may close off the drainage angle and cause a dangerously high eye pressure. When the drainage angle of the eye suddenly becomes completely blocked, pressure builds up rapidly, and this is called acute angle-closure glaucoma. The symptoms include severe eye pain, blurred vision, headache, rainbow haloes around lights, nausea and vomiting. Unless an ophthalmologist treats acute angle-closure glaucoma quickly, blindness can result. When the drainage angle of the eye gradually becomes completely blocked, pressure builds up gradually, and this is called chronic angle-closure glaucoma. This form of glaucoma occurs more frequently in people of African and Asian ancestry, and in certain eye conditions.
- Nail-Patella syndrome
- Nail-Patella syndrome (NPS) is a rare genetic disorder (estimated to occur in one in 50,000 newborns) that causes abnormalities of bone, joints, fingernails, kidneys, and glaucoma.
Other Types of Glaucoma
Not all types of glaucoma are characterized by eye pressures. In normal-tension or low-tension glaucoma, the optic nerve suffers damage with the resulting visual field loss even though normal eye pressures are maintained. Eyes afflicted with this condition are far more susceptible to optic nerve damage with any increase in the intraocular pressure compared to other eyes.
- Exfoliation syndrome
- Exfoliation syndrome is a common form of open-angle glaucoma that results when there is a buildup of abnormal, whiteish material on the lensand drainage angle of the eye. This material and pigment from the back of the iris can clog the drainage system of the eye, causing increased eye pressure. This form of glaucoma responds well to laser treatment.
- Pigmentary glaucoma
- Pigmentary glaucoma is a condition that typically affects young, nearsighted, Caucasian males. This condition is characterized by the iris bowing backwards, and coming into contact with the support structures that hold the lens in place. This position disrupts the cells lining the back surface of the iris containing pigment, and results in a release of pigment particles into the drainage system of the eye. This pigment can clog the drain and can lead to an increase in eye pressure. This form of glaucoma responds well to laser treatment.
Other types of glaucoma may be caused by injuries to the eye, tumors, and other eye diseases. A rare type of glaucoma can even be present in children at birth.
Unfortunately, most cases of glaucoma do not occur with readily noticable symptoms that warn of the irreversible optic nerve damage being done. However, the presence of the following warning signs, indicates that you need a thorough examination by an eye doctor:
- Unusual trouble adjusting to dark rooms
- Difficulty focusing on near or distant objects
- Squinting or blinking due to unusual sensitivity to light or glare
- Change in color of iris
- Red-rimmed, encrusted or swollen lids
- Recurrent pain in or around eyes
- Double vision
- Dark spot at the center of viewing
- Lines and edges appear distorted or wavy
- Excess tearing or "watery eyes"
- Dry eyes with itching or burning; and
- Seeing spots, ghost-like images
The following may be indications of potentially serious problems that might require emergency medical attention:
- Sudden loss of vision in one eye
- Sudden hazy or blurred vision
- Flashes of light or black spots
- Halos or rainbows around light
The symptoms listed above may not necessarily mean that you have glaucoma. However, if you experience one or more of these symptoms, contact your eye doctor for a complete exam.
Regular eye examinations by your ophthalmologist are the best way to detect glaucoma. Your ophthalmologist will measure your eye pressure (tonometry); inspect the drainage angle of your eye (gonioscopy); evaluate your optic nerve (ophthalmolscopy); and test the visual field of each eye (perimetry). Optic nerve evaluation and visual field testing are performed at regular intervals to monitor the effects of glaucoma. The information from these tests provides an indication of the effectiveness of the treatment being used and whether further treatments may be necessary. Not all of these tests are necessary for every person, nor at every visit. The objective is to determine if glaucoma damage has progressed over time.
High eye pressure alone does not mean that you have glaucoma, but it is an important risk factor your ophthalmologist will use to determine your risk for developing the disease.
The most important risk factors include:
- elevated eye pressure
- African ancestry
- thin cornea
- family history of glaucoma
- past injuries to the eyes
- steroid use
- a history of severe anemia or shock
According to a recent study by researchers at the University of Michigan Kellogg Eye Center, individuals with diabetes and hypertension may also have an increased risk of developing open-angle glaucoma (OAG). Read about the glaucoma study.
Listen as Kellogg glaucoma specialist Joshua D. Stein, M.D., M.S. talks about this potential risk.
Risk of Glaucoma
Joshua D. Stein, M.D., M.S. | 29 Sept 2011 | MP3 01:03
Your ophthalmologist will weigh all of these factors before deciding if you need treatment for glaucoma; or whether you should be monitored regularly as a glaucoma suspect to detect the early signs of damage to the optic nerve.
The treatment for glaucoma depends upon the nature and severity of each case. In general, glaucoma cannot be cured, but it can be controlled. Eye drops, pills, laser procedures, and surgical operations are used to prevent or slow further damage from occurring. With any type of glaucoma, regular eye examinations are very important to detect progression and to prevent vision loss. Because glaucoma can worsen without your being aware of it, your treatment will likely need to be changed over time to achieve a lower "target eye pressure."
Glaucoma is often treated with eye drops taken regularly several times a day, sometimes in combination with pills. These medications will alter the circulation of eye fluid and lower eye pressure, either by decreasing the production of fluid within the eye, or by increasing the flow leaving the drainage angle. It is important to tell all of your doctors about the eye medications you are using because glaucoma medications can have side-effects. You should notify your ophthalmologist immediately if you think you may be experiencing side-effects. Side-effects from some eye drops may include a stinging sensation, red eyes, blurred vision, headaches, or changes in pulse, heartbeat or breathing. Side-effects from pills may include tingling of fingers and toes, drowsiness, loss of appetite, bowel irregularities, kidney stones, anemia or bleeding disorders.
Laser surgery is also effective for glaucoma treatment. Trabeculoplasty is laser treatment to enhance the eye drain age function to control eye pressure within the eye when treating open-angle glaucoma. Iridotomy is laser treatment to create tiny holes in the iris to improve the flow of eye fluid to the drain when treating narrow angle glaucoma.
When operative surgery is needed to treat glaucoma, your ophthalmologist will use a microscope and specialized instruments to create a new bypass drainage channel for the eye fluid to leave the eye. The new channel helps to lower the eye pressure. Surgery will be recommended only if your ophthalmologist feels the benefit of a lower eye pressure achieved with an operation outweighs possible complications and/or further progression of optic nerve damage.
These websites are not operated by the University of Michigan Kellogg Eye Center. Kellogg Eye Center is not associated with these websites in any way, nor does it endorse or take responsibility for any of the content. These links are provided for the convenience of our users.
American Academy of Ophthalmology
Symptoms, diagnosis and treatment of glaucoma along with diagrams and video clips
MedlinePlus (National Library of Medicine)
Extensive list of links from excellent sources.
- Glaucoma Tutorial
Interactive multimedia presentation, requires Macromedia Flash Player (available onsite for download)
National Eye Institute
- Glaucoma Facts
Answers questions about causes and symptoms, and discusses diagnosis and types of treatment
- Glaucoma: What You Should Know
A 24-page large print booklet (in pdf format) discussing causes, symptoms, diagnosis, and treatment options for open-angle glaucoma
- Glaucoma: How Much Do You Know?
A 10-question online quiz covering risk factors and treatment issues
National Institutes of Health
NIH's SeniorHealth website covers the topic of Glaucoma. Contains several short online video clips.
WebMD's section on Glaucoma, includes links to medical reference pages, and an online video
The Glaucoma Foundation
- Patient Guide
This comprehensive (16-page) Patient's Guide describes the different types of glaucoma, diagnosis and treatment
Prevent Blindness America
- Glaucoma Learning Center
Extensive coverage of Glaucoma, includes treatment options, and an online discussion forum
For more information, see the Glaucoma, Cataract, and Anterior Segment Disease Clinic and the complete Clinic Services listing of the U-M Kellogg Eye Center.