Saturday, 6 January 2018

Understanding Glaucoma : Types, Symptoms And Warnings


Glaucoma is the name given to a group of eye diseases where vision is lost due to damage to the optic nerve. Approximately 300,000 Australians have glaucoma. Generally there are no symptoms or warning signs in the early stages of this eye condition. The loss of sight is usually gradual and a considerable amount of peripheral (side) vision may be lost before there is an awareness of any problem.

Glaucoma is a leading cause of blindness for people over 60 years old. But blindness from glaucoma can often be prevented with early treatment. Glaucoma is relatively common, especially in older adults and can cause damage to the optic nerve if left untreated.
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Types Of Glaucoma
Glaucoma is the term applied to a group of eye diseases that gradually result in loss of vision by permanently damaging the optic nerve, the nerve that transmits visual images to the brain. The leading cause of irreversible blindness, glaucoma often produces no symptoms until it is too late and vision loss has begun.

Primary Open-angle glaucoma : This is the most common type of glaucoma. It happens gradually, where the eye does not drain fluid as well as it should (like a clogged drain). As a result, eye pressure builds and starts to damage the optic nerve. This type of glaucoma is painless and causes no vision changes at first. Some people can have optic nerves that are sensitive to normal eye pressure. This means their risk of getting glaucoma is higher than normal. Regular eye exams are important to find early signs of damage to their optic nerve.


Angle-closure Glaucoma : It’s less common in the West than in Asia. You may also hear it called acute or chronic angle-closure or narrow-angle glaucoma. Your eye doesn’t drain right because the angle between your iris and cornea is too narrow. Your iris is in the way. This can cause a sudden buildup of pressure in your eye. It’s also linked to farsightedness and cataracts, a clouding of the lens inside your eye.

Exfoliative glaucoma (pseudoexfoliation or PXE) is another type of glaucoma that can occur with either open or closed angles. This type of glaucoma is characterized by deposits of flaky material on the front surface of the lens (anterior capsule) and in the angle of the eye. The accumulation of this material in the angle is believed to block the drainage system of the eye and raise the eye pressure. While this type of glaucoma can occur in any population, it is more prevalent in older people and people of Scandinavian descent. It has recently been shown to often be associated with hearing loss in older people.

Pigmentary glaucoma is a type of secondary glaucoma that is more common in younger men. In this condition, for reasons not yet understood, granules of pigment detach from the iris, which is the colored part of the eye. These granules then may block the trabecular meshwork, which, as noted above, is a key element in the drainage system of the eye. Finally, the blocked drainage system leads to elevated intraocular pressure, which results in damage to the optic nerve.

Congenital (infantile) glaucoma is a relatively rare, inherited type of open-angle glaucoma. In this condition, the drainage area is not properly developed before birth. This results in increased pressure in the eye that can lead to the loss of vision from optic-nerve damage and also to an enlarged eye. The eye of a young child enlarges in response to increased intraocular pressure because it is more pliable than the eye of an adult. Early diagnosis and treatment with medication and/or surgery are critical in these infants and children to preserve their sight.

Congenital glaucoma : This inherited form of glaucoma is present at birth, with 80 percent of cases diagnosed by age one. These children are born with narrow angles or some other defect in the drainage system of the eye.

Symptoms Of Glaucoma
Glaucoma often is called the "silent thief of sight," because most types typically cause no pain and produce no symptoms until noticeable vision loss occurs. For this reason, glaucoma often progresses undetected until the optic nerve already has been irreversibly damaged, with varying degrees of permanent vision loss.

These symptoms can be brief or last a few hours but, if caused by glaucoma, will continue to occur.
◾Blurry or hazy vision: Vision is no longer clear. Crisp, bold objects can become obscured and hard to focus on. The clear surface of your eye may also appear hazy.
◾Rainbow circles/bright lights: A rainbow halo around bright lights and/or light split in different directions indicate/s a problem in the way the eye receives light.
◾Headaches and nausea: The pressure may spread throughout your head, causing an extreme headache. This can be accompanied by nausea, or nausea may occur by itself.
◾Eye pain: Severe hurting within and around the eye.
◾Loss of vision: A progressive loss of sight.


Author: Richard Smith