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Glaucoma is a disease of the optic nerve in which the nerve is damaged, in most cases, by excessive intraocular pressure (IOP). Glaucoma may also be present when IOP is normal. Other factors which may contribute to glaucoma are nerve cell death and reduced blood flow. Some cases of glaucoma have been caused by various drugs (particularly those that cause pupil dilation) and also as a complication of other eye surgery.
There are several kinds of glaucoma, although the two main categories are open-angle glaucoma and closed-angle glaucoma.
OPEN-ANGLE GLAUCOMA
Most glaucoma patients suffer from this type. Usually starting in one eye and progressing to the other, this type of glaucoma is brought about when the fluid drainage angle within the eye is open but the drainage channels are closed. This creates a fluid build-up and pressure on the optic nerve increases. Over time, the nerves at the back of the eye are exposed to increasing pressure. Peripheral vision is lost first. By the time all peripheral vision is lost, damage is irreversible. Tunnel vision remains after the peripheral vision is lost, with the patient only able to see what is directly ahead. If not treated, and the pressure not reduced, this condition can damage the eye until complete vision is lost.
Although open-angle glaucoma is not caused by one single factor, several elements are known to contribute to risk for the disease. Aging, genetics, lack of healthy eye blood vessels and high levels of glutamates (amino acid which stimulates eye nerve cells) can all increase the risk for glaucoma. With chronic open-angle glaucoma, the symptoms may be so mild that none are noticed until irreversible damage has been done.
CLOSED-ANGLE GLAUCOMA
In closed-angle glaucoma, the iris is pushed against the lens of the eye, shutting off the drainage angle. Sometimes the lens and the iris stick to each other. This results in a build-up of pressure. Pressure increases suddenly, usually in one eye. There may be a feeling of fullness in the eye along with reddening, swelling and blurred vision. This is an emergency situation and medical attention should be obtained immediately. Emergency surgery may be needed to allow fluid to flow freely. This type of glaucoma is often caused by some type of defect in the eye structure.
With chronic closed-angle glaucoma, there are no such sudden symptoms. Progress is slow and painless. Acute closed-angle glaucoma occurs more often in African-Americans than whites. Those of Asian and African descent are more prone to chronic closed-angle glaucoma.
In many cases, glaucoma is not a result of excessive intraocular pressure. Glaucoma may be present in individuals whose IOP is normal just as those with increased eye pressure may not suffer from glaucoma. Glaucoma may be present at birth in the case of infants who are born with underdeveloped drainage canals. This rarely occurs but it usually corrected successfully with surgery.
Diseases such as diabetes can increase glaucoma risk. A correlation has also been shown between open-angle glaucoma and those suffering from hypothyroidism, leukemia and arthritis. Those who use corticosteroids may increase their risk for this condition if taking them over a long period but may reverse the damage of oral corticosteroids by discontinuiing their use.
Early detection is very important in diagnosing and treating glaucoma. Tests for eye pressure, optic nerve damage and peripheral vision should be conducted. Although readings from eye pressure tests may not signal a problem, they should always be included.
If an individual has the type of glaucoma that does not stem from elevated IOP, no treatment is available. After the optic nerve fibers are destroyed, the damage is irreversible. For those who suffer from pressure-induced glaucoma, various treatments exist. Drugs and/or surgery are been very successful measures. Some alternative treatments include eliminating caffeine, vitamin E supplements, etc. Relaxation, stress reduction and various exercises are recommended by some but any motion that puts the head below the waist area should be avoided if glaucoma is a problem since these movements may increase pressure within the eye. Also, before using any alternative method of treatment, a physician should be consulted.
Laser surgery has become a very common procedure used for vision correction with glaucoma sufferers. The operations are very quick, usually lasting for less than twenty minutes, and are painless. This operation can lower IOP very rapidly and create a passage for fluid drainage if needed. This surgery has a high success rate although medication may be needed to maintain the lower pressure.
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