Glaucoma


Glaucoma is a disease of the eye in which fluid pressure within the eye rises - if left untreated the patient may lose vision, and even become blind. The disease generally affects both eyes, although one may have more severe signs and symptoms than the other.

Why Does Pressure Rise in the Eye to Cause Glaucoma?

Glaucoma usually occurs when pressure in your eye increases. This can happen when eye fluid isn't circulating normally in the front part of the eye.

Glaucoma Eye

Normally, this fluid, called aqueous humor, flows out of the eye through a mesh-like channel. If this channel becomes blocked, fluid builds up, causing glaucoma. The direct cause of this blockage is unknown, but doctors do know that it can be inherited, meaning it is passed from parents to children.

Less common causes of glaucoma include a blunt or chemical injury to the eye, severe eye infection, blockage of blood vessels in the eye, inflammatory conditions of the eye, and occasionally eye surgery to correct another condition. Glaucoma usually occurs in both eyes, but it may involve each eye to a different extent.


What are the symptoms of Glaucoma?

Chronic (primary open-angle) glaucoma is the most common type. It has no symptoms until eye sight is lost at a later stage.

Glaucoma Eye Symptoms

Damage progresses very slowly and destroys vision gradually, starting with the side vision. One eye covers for the other, and the person remains unaware of any problem until a majority of nerve fibres have been damaged, and a large part of vision has been destroyed. This damage is irreversible. It is progressive and usually relentless. Treatment cannot recover what has been lost. But it can arrest, or at least, slow down the damage process. That is why it is so important to detect the problem as early as possible, to be able to start treatment with as little damage to the vision as possible.

Who is at risk?

Glaucoma most often occurs in adults over age 40, but it can also occur in young adults, children, and even infants. In some people, glaucoma occurs more frequently and at an earlier age and with greater loss of vision.

You are at an increased risk of glaucoma if you:
• Are over age 40
• Have a family history of glaucoma
• Have poor vision
• Have diabetes
• Take certain steroid medications, such as prednisone
• Have had trauma to the eye or eyes

What are the types of Glaucoma?

Open-angle glaucoma is the most common form. Some people have other types of the disease.

Open-angle glaucoma: Also called wide-angle glaucoma, this is the most common type of glaucoma. The structures of the eye appear normal, but fluid in the eye does not flow properly through the drain of the eye, called the trabecular meshwork.

Angle-closure glaucoma: Also called acute or chronic angle-closure or narrow-angle glaucoma, this type of glaucoma is less common in the West than in Asia. Poor drainage is caused because the angle between the iris and the cornea is too narrow and is physically blocked by the iris. This condition leads to a sudden buildup of pressure in the eye.

How is glaucoma detected?

Glaucoma is detected through a comprehensive dilated eye exam that includes the following:

Visual acuity test: This eye chart test measures how well you see at various distances.

Visual field test: This test measures your peripheral (side vision). It helps your eye care professional tell if you have lost peripheral vision, a sign of glaucoma.

Dilated eye exam: In this exam, drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.

Tonometry is the measurement of pressure inside the eye by using an instrument called a tonometer. Numbing drops may be applied to your eye for this test. A tonometer measures pressure inside the eye to detect glaucoma.

Pachymetry is the measurement of the thickness of your cornea. Your eye care professional applies a numbing drop to your eye and uses an ultrasonic wave instrument to measure the thickness of your cornea.

How is glaucoma treated?

Treatment can involve glaucoma surgery, lasers or medication, depending on the severity. Eye drops with medication aimed at lowering IOP usually are tried first to control glaucoma.

Because glaucoma often is painless, people may become careless about strict use of eye drops that can control eye pressure and help prevent permanent eye damage.

In fact, non-compliance with a program of prescribed glaucoma medication is a major reason for blindness caused by glaucoma.

If you find that the eye drops you are using for glaucoma are uncomfortable or inconvenient, never discontinue them without first consulting your eye doctor about a possible alternative therapy.