Glaucoma

Imagine seeing the world through a tube - a tube that could eventually close, leaving you in the dark. This is the destiny many glaucoma patients face. Glaucoma is one of the leading causes of blindness in the U.S. It most often occurs in people over age 40. People with a family history of glaucoma, African Americans, and those who are very nearsighted or diabetic are at a higher risk of developing the disease.

Glaucoma usually begins when pressure builds up in the aqueous fluid of the eye (this fluid bathes the inside of the eye, unlike tears which bathe the outside). This pressure (intraocular pressure) can damage the optic nerve. The optic nerve sends messages to the brain so that you can see.

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Aqueous fluid is made inside the eye and bathes tissues in the front part of the eye before being drained away through a sieve-like system called the trabecular meshwork. The eye is always producing fluid. The eye's drainage areas may become clogged or blocked. Too much fluid stays in the eye. This increases eye pressure.
 

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Open-angle is the most common kind of glaucoma. It occurs slowly as people age. The drainage area in the eye becomes clogged. Not enough fluid drains from the eye, so pressure slowly builds up. This causes gradual loss of side (peripheral) vision. You may not even notice changes until much of your vision is lost.

Closed-angle (acute) glaucoma is less common than open-angle. It usually comes on quickly. The drainage area in the eye suddenly becomes completely blocked. Eye pressure builds rapidly. You may notice blurred vision and rainbow halos around lights. You may also have headaches, nausea, vomiting and severe pain. If not treated right away, blindness can occur.

Risk factors for glaucoma include:
* elevated pressure within the eye (intraocular pressure)
* positive family history of glaucoma
* increasing age
* associated conditions: high blood pressure, diabetes, myopia (short-sightedness).

The older you are and the more risk factors you have, the more important it is to have regular eye examinations.

Gradual loss of vision in open-angle glaucoma, usually without other warning symptoms, progresses from the periphery (sides) to the centre of your visual field (e.g., the animated image below). Most people learn they have glaucoma during an eye exam. Simple tests that measure your eye pressure and magnify the inside of your eye usually alert your eye doctor to a problem. Other tests reveal loss of vision and damage to the delicate structures of the eye.

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The most common type of glaucoma develops gradually and painlessly, without symptoms. A rarer type occurs rapidly and its symptoms may include blurred vision, loss of side vision, seeing colored rings around lights and pain or redness in the eyes.

Glaucoma cannot be prevented, but if diagnosed and treated early, it can be controlled. Vision lost to glaucoma cannot be restored. The treatment for glaucoma includes prescription eye drops and medicines to lower the pressure in your eyes. In some cases, laser treatment or surgery may be effective in reducing pressure.


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