It most often occurs in people over age 40, although an infant congenital form of glaucoma exists. People with a family history of glaucoma, African Americans over the age of 40 and Hispanics over the age of 60 have an increased risk of developing glaucoma.
Other risk factors include thinner corneas, chronic eye inflammation and taking medications that increase the pressure in the eyes. The most common form of glaucoma, primary open-angle glaucoma , develops slowly and usually without any symptoms.
Many people are not aware they have the condition until they have significant vision loss. Initially, glaucoma affects peripheral or side vision, but it can advance to central vision loss. If left untreated, glaucoma can lead to significant vision loss in both eyes, and may even lead to blindness.
A less common type of glaucoma, acute angle-closure glaucoma , usually occurs abruptly due to a rapid increase of pressure in the eye. Its symptoms may include severe eye pain, nausea, redness in the eye, seeing halos or colored rings around lights and blurred vision. This is an emergency condition in which severe vision loss can occur quickly; see your doctor of optometry immediately. Glaucoma cannot currently be prevented. But if it is diagnosed and treated early, it can usually be controlled.
Medication or surgery can slow or prevent further vision loss. However, vision already lost to glaucoma cannot be restored. That is why the American Optometric Association recommends an annual dilated eye examination for people at risk for glaucoma. Depending on your specific condition, your doctor may recommend more frequent examinations.
There are many theories about the causes of glaucoma, but the exact cause is unknown. Although the disease is usually associated with an increase in fluid pressure inside the eye, other theories include a lack of adequate blood supply to the nerve.
This is the most common form of glaucoma. Damage to the optic nerve is slow and painless. Those affected can lose a large portion of vision before they notice any vision problems. One theory about its development is that the eye's drainage system becomes inefficient over time. This leads to an increased amount of fluid and a gradual buildup of pressure within the eye.
Another theory about the cause of this type of glaucoma is that there is poor blood flow perfusion to the optic nerve. Other theories also exist. This type of glaucoma, also called closed-angle glaucoma or narrow-angle glaucoma, is a less common form of the disease. It is a medical emergency that can cause vision loss within a day of its onset.
It occurs when the drainage angle in the eye formed by the cornea and the iris closes or becomes blocked. Many people who develop this type of glaucoma have a very narrow drainage angle. With age, the lens in the eye becomes larger, pushing the iris forward and narrowing the space between the iris and the cornea.
As this angle narrows, the fluid in the eye is blocked from the drainage system. Therefore the fluid builds up and eye pressure increases. Angle-closure glaucoma can be chronic progressing gradually or acute appearing suddenly.
The acute form occurs when the iris completely blocks fluid drainage. When people with a narrow drainage angle have their pupils dilated, the angle may close and cause a sudden increase in eye pressure.
Although an acute attack often affects only one eye, the other eye may be at risk of an attack as well. This type of glaucoma results from an injury or another eye disease. It may be caused by a variety of medical conditions, medications, physical injuries, and eye abnormalities. Infrequently, eye surgery can lead to secondary glaucoma. In this form of glaucoma, eye pressure remains within the "normal" range, but the optic nerve is damaged nevertheless.
It is not known why this happens. Possibly, people with low-tension glaucoma have an abnormally sensitive optic nerve.
Or they may have a reduced blood supply to the optic nerve caused by a condition such as atherosclerosis, a hardening of the arteries. Under these circumstances, even normal pressure on the optic nerve can cause damage.
The signs or symptoms of glaucoma can vary depending on the type. Primary open-angle glaucoma often develops slowly and painlessly, with no early warning signs. It can gradually destroy one's vision without even knowing it. The first indication that a person has glaucoma may occur after some vision has been lost. Acute angle-closure glaucoma results from a sudden blockage of drainage channels in the eye, causing a rapid buildup of pressure. In this form of the disease, a patient would have blurred vision, the appearance of halos or colored rings around lights, and pain and redness in the eye.
Glaucoma is diagnosed through a comprehensive eye examination. Because glaucoma is a progressive disease, meaning it worsens over time, a change in the appearance of the optic nerve, a loss of nerve tissue, and a corresponding loss of vision confirm the diagnosis.
Some optic nerves may resemble nerves with glaucoma, but the patients may have no other risk factors or signs of glaucoma. These patients should have routine comprehensive exams to monitor any changes. Here is more information about glaucoma and some examples of what a person with advanced glaucoma sees. Glaucoma is a group of eye diseases that can cause vision loss and blindness by damaging the nerve in the back of your eye, known as the optic nerve.
The increased pressure in your eye, called intraocular pressure IOP , can damage your optic nerve, which sends images to your brain. You gradually lose vision as optic nerve cells degenerate. By the time the individual experiences noticeably decreased vision, the disease is frequently in its more severe stages. The symptoms can start so slowly that you may not notice them. This internal fluid normally drains out through a tissue called the trabecular meshwork at the angle where the iris and cornea meet.
When fluid is overproduced or the drainage system doesn't work properly, the fluid can't flow out at its normal rate and eye pressure increases. Glaucoma tends to run in families. In some people, scientists have identified genes related to high eye pressure and optic nerve damage. Open-angle glaucoma is the most common form of the disease. The drainage angle formed by the cornea and iris remains open, but the trabecular meshwork is partially blocked.
This causes pressure in the eye to gradually increase. This pressure damages the optic nerve. It happens so slowly that you may lose vision before you're even aware of a problem.
Angle-closure glaucoma, also called closed-angle glaucoma, occurs when the iris bulges forward to narrow or block the drainage angle formed by the cornea and iris. As a result, fluid can't circulate through the eye and pressure increases. Some people have narrow drainage angles, putting them at increased risk of angle-closure glaucoma. Angle-closure glaucoma may occur suddenly acute angle-closure glaucoma or gradually chronic angle-closure glaucoma.
Acute angle-closure glaucoma is a medical emergency. In normal-tension glaucoma, your optic nerve becomes damaged even though your eye pressure is within the normal range. No one knows the exact reason for this. You may have a sensitive optic nerve, or you may have less blood being supplied to your optic nerve.
This limited blood flow could be caused by atherosclerosis — the buildup of fatty deposits plaque in the arteries — or other conditions that impair circulation. It's possible for infants and children to have glaucoma. It may be present from birth or develop in the first few years of life.
The optic nerve damage may be caused by drainage blockages or an underlying medical condition. In pigmentary glaucoma, pigment granules from your iris build up in the drainage channels, slowing or blocking fluid exiting your eye.
Activities such as jogging sometimes stir up the pigment granules, depositing them on the trabecular meshwork and causing intermittent pressure elevations. Because chronic forms of glaucoma can destroy vision before any signs or symptoms are apparent, be aware of these risk factors:.
These self-care steps can help you detect glaucoma in its early stages, which is important in preventing vision loss or slowing its progress.
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