Glaucoma: The 'Silent Thief' reveal Its Secrets
Glaucoma - group of diseases that damage the optic nerve is some times called as " The Silent Thief of Sight ", because it slowly damages the eyes and can cause irreparable harm before there is any vision loss. Optic Nerve is main connective nerve between brain and eye, Glaucoma damages the optic nerve that causes loss of vision.
There are treatments to delay vision loss, but no cure, making it a leading cause of blindness all over the world. It affects more than 2.7 million people in the United States and more than 60 million worldwide. There are many forms of the disease, but primary open-angle glaucoma is the most common form and the most mysterious.
"Primary open-angle glaucoma remains a black box, but researchers are pursuing many avenues to investigate the underlying causes. As we develop a better understanding of the disease process, we hope this will lead to new, more effective treatments and possibly even preventive therapies for it," said Hemin Chin, Ph.D., director of the Glaucoma and Optic Neuropathies program at the National Eye Institute (NEI), part of the National Institutes of Health.
If you've ever had an air-puff test, also known as tonometry, then you may have heard that glaucoma is linked to an increase in eye pressure, or intraocular pressure. The unique anatomy of the eye, when combined with other factors, can cause a rise in eye pressure that can in turn cause some types of glaucoma.
The front of the eye, between the cornea (the eye's front window) and the iris (the colored part of the eye), is filled with a clear fluid. This fluid leaves the eye and enters the blood by passing through a gap at the angle where the cornea and iris meet. The gap is filled with a sponge-like tissue called the trabecular meshwork, which helps regulate fluid passage. Sometimes, eye infections, injuries, or certain medications can narrow the gap and compress this spongy tissue, producing a rapid buildup of fluid and eye pressure. This is called angle-closure glaucoma.
In the United States, open-angle glaucoma is more common than angle-closure glaucoma, affecting about three times as many people. It has a more gradual course and there are no clear signs of blockage within the eye's drainage system. Yet, researchers estimate that 50 to 80 percent of people with open-angle glaucoma have eye pressure that is higher than average. Others have normal pressure or even low pressure. On the flip side, many people have high eye pressure but never develop glaucoma.
"Elevated intraocular pressure is a leading risk factor for primary open-angle glaucoma," said Robert N. Weinreb, M.D., chair and distinguished professor of ophthalmology, and director of the Hamilton Glaucoma Center at the University of California, San Diego (UCSD). "The higher the intraocular pressure, the more likely the person is to develop glaucoma and the more likely it is to progress."
Because of these data, medications that lower eye pressure are a mainstay of glaucoma treatment. In some cases, a doctor may recommend surgery to increase fluid drainage from the eye. Drugs, surgery, or both approaches together are often successful at slowing the course of open-angle glaucoma. The NEI-funded Ocular Hypertension Treatment Study also found that pressure-lowering eye drops can delay the onset of glaucoma in people with high eye pressure. But even with medication or surgery, open-angle glaucoma usually continues to attack the optic nerve and cause gradual vision loss.
Source : National Eye Institute (NEI)
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