Glaucoma



Glaucoma, an eye disease, is one of the complications of diabetes. It has been described as a "silent thief" as it stills the vision slowly before one realizes that anything is wrong with his/ her vision. Glaucoma is not a single disease or complication of the eye - it is a group of them with a common feature - the common feature being damage to the optic nerve. This damage is generally accompanied by high pressure inside the eyeball. The optic nerve consists of more than a million nerve fibers at the back of the eye, carrying impulses of the image to the brain. If optic nerve deteriorates due to glaucoma, blind spots develop in the path of vision. The medical advances have resulted into very good treatment of glaucoma if detected at an early stage. However, if left untreated or poorly treated, glaucoma may lead to deterioration in the vision and may result into partial or complete loss of vision.

Signs and symptoms


Glaucoma does not occur in any particular way. It manifests and affects in a variety of ways, and depending on a particular variety its signs ans symptoms also differ.


 * Primary open-angle glaucoma: This particular variety of glaucoma continues to advance without any serious sign or symptom until it has reached an advanced stage. The increased pressure in the eyeball continues to damage the optic nerve and this damages peripheral vision, and damage to peripheral vision continues if left untreated. In an advanced stage, tunnel vision develops and ultimately vision may be affected very adversely including the loss of vision. At the initial state, open-angle glaucoma affects both eyes though serious or complete loss of vision occur in one eye only. However, ultimately both eyes may be affected.


 * Acute angle-closure glaucoma: It develops at a rapid pace due to sudden rise in the pressure in the eyeball. In some case, complete loss of vision may occur within a day of the attack. It requires immediate medical care. Generally, it occurs during evenings or in a relatively dark room or place "when the light is dim" and "pupils have become relatively dilated". It is painful too. Some of its signs and symptoms include:
 * Vision becomes blurred,
 * One sees halos around lights,
 * Eyes become unusually read,
 * There is severe pain in the eye, and
 * Nausea and vomiting may take palce.

Further, both open-angle and angle-closure glaucoma have two divisions - primary or secondary. In primary condition, the exact cause remains unknown while in the secondary condition, one or more causes may be identified.

Risk factors
In case the internal pressure in the eye (medical term: intraocular pressure) remains higher than the normal, there is a risk of developing glaucoma. However, everyone with elevated internal pressure in the ey does not develop glaucoma. As such, it is rather difficult to predict the development of glaucoma. Certain factors increase the risk of glaucoma:


 * Family history & race: Having a family history of glaucoma puts one at a higher risk bracket of glaucoma - there is perhaps a genetic link and hereditary factors putting such a person at a higher risk of developing glaucoma. Likewise, certain ethnic groups are also more prone to developing glaucoma though exact reasons for the same are not ascertainable till now.
 * Age: It is a significant risk factor. Persons older than 60 are at a higher risk of developing glaucoma than the persons of younger age. The risk increases after 40s.
 * Physical injuries: Physical injuries and severe trauma like being badly hit on the eyes increases the risk of glaucoma. Some other risk factors include detachment of retina, tumors in the eye, continued condition of severe eye inflammations, etc.
 * Medical conditions: Some medical conditions like diabetes, high blood pressure and/or heart disease increase the risk of glaucoma.
 * Nearsightedness: This condition is also a risk factor.
 * Corticosteroid use: Use of corticosteroids for a long period exposes one to a higher risk of glaucoma.
 * Abnormalities in the eye: Certain structural abnormalities of the eye exposes the person so affected to a higher risk of secondary glaucomacan. For instance, pigmentary glaucoma which is a form of secondary glaucoma is caused by pigment granules released from the back of the iris.

Prevention
In most of the cases, glaucoma is detected suddenly when the disease has already advanced. As such, regular check up is required to detect it, monitor it, and ensure proper treatment. As a thumb rule, for persons between the ages of 40 and 65, comprehensive eye examination every four year has been suggested while it should be done every year or alternate year for persons older than 65.

As regards the treatment, Mayo Clinic has indicated as follows :
 * 1) "Until recently, there was no proven way to prevent glaucoma. But a large multicenter trial, supported by the National Eye Institute, found that when glaucoma eyedrops were given daily to people with elevated eye pressure (above 24 mm Hg), they reduced eye pressure an average of 22 percent. More important, the researchers discovered that daily use of eyedrops can reduce the risk of developing glaucoma by nearly half in blacks with elevated eye pressure."
 * 2) "Another study found that cholesterol-lowering medications reduced the risk of open-angle glaucoma, especially for people who already have cardiovascular disease. Although this may be an added benefit for those already taking these medications to reduce their cholesterol levels, more studies need to be done to confirm the reduction in risk of glaucoma."