Glaucoma a silence thief of sight

Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently impacting vision in the affected eye(s) and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye.

The nerve damage involves loss of retinal ganglion cells in a characteristic pattern. There are many different sub-types of glaucoma but they can all be considered a type of optic neuropathy. One person may develop nerve damage at a relatively low pressure, while another person may have high eye pressure for years and yet never develop damage. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness.

Glaucoma can be divided roughly into two main categories, "open angle" and "closed angle" glaucoma. Closed angle glaucoma can appear suddenly and is often painful; visual loss can progress quickly but the discomfort often leads patients to seek medical attention before permanent damage occurs. Open angle, chronic glaucoma tends to progress at a slower rate and the patient may not notice that they have lost vision until the disease has progressed significantly.

Glaucoma has been nicknamed the "silent thief of sight" because the loss of vision normally occurs gradually over a long period of time and is often only recognized when the disease is quite advanced. Once lost, this damaged visual field cannot be recovered. Worldwide, it is the second leading cause of blindness.Glaucoma affects 1 in 200 people aged fifty and younger, and 1 in 10 over the age of eighty. If the condition is detected early enough it is possible to arrest the development or slow the progression with medical and surgical means.

Glaucoma is a leading cause of blindness in the United States. Although anyone can get glaucoma, the following people are at higher risk:

African Americans over age 40
Everyone over age 60, especially Mexican Americans
People with a family history of glaucoma.

What are the symptoms?

At first, there are no symptoms. Vision stays normal, and there is no pain.

However, as the disease progresses, a person with glaucoma may notice his or her side vision gradually failing. That is, objects in front may still be seen clearly, but objects to the side may be missed. As the disease worsens, the field of vision narrows and blindness results.

How is it detected?

Many people may know of the "air puff" test or other tests used to measure eye pressure in an eye examination. But this test alone cannot detect glaucoma. Glaucoma is found most often during an eye examination through dilated pupils. Dilating pupils involves putting drops into the eyes during the exam to enlarge the pupils. This procedure allows the eye care professional to see more of the inside of the eye to check for signs of glaucoma.

How can it be treated?

Although open-angle glaucoma cannot be cured, it can usually be controlled. The most common treatments are as follows:

Medications: These may be either in the form of eyedrops or pills. Some drugs are designed to reduce pressure by slowing the flow of fluid into the eye. Others help to improve fluid drainage.

For most people with glaucoma, regular use of medications will control the increased fluid pressure. But these drugs may stop working over time, or they may cause side effects. If a problem occurs, the eye care professional may select other drugs, change the dose, or suggest other ways to deal with the problem.
Laser surgery: During laser surgery, a strong beam of light is focused on the part of the anterior chamber where the fluid leaves the eye. This surgery results in a series of small changes that make it easier for fluid to exit the eye. Over time, the effect of laser surgery may wear off. Patients who have this form of surgery may need to keep taking glaucoma drugs.
Surgery: Surgery can also help fluid escape from the eye and thereby reduce the pressure. However, surgery is usually reserved for patients whose pressure cannot be controlled with eyedrops, pills, or laser surgery.

What research is being done?

Scientists in the United States are conducting research to learn what causes glaucoma and to improve its diagnosis and treatment. For example, researchers have discovered genes that could help explain how glaucoma damages the eye.

NEI is funding a number of studies to find out what causes fluid pressure to increase in the eye. By learning more about this process, doctors may be able to find the exact cause of the disease and learn better how to prevent and treat it. NEI supports studies to learn more about who is likely to get glaucoma, when to treat people with increased pressure, and which treatment to use first. NEI also supports clinical trials of new drugs and surgical techniques that show promise against glaucoma.

( Courtesy: National Eye Institute http://www.nei.nih.gov/ )