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Treatment Glaucoma

Glaucoma is a group of diseases that can damage the eye's optic nerve and result in vision loss and blindness. Early treatment is important to prevent serious vision loss.

Types

There are 5 types of glaucoma:

  1. Open-angle glaucoma. This is the most common type. It is characterized by slowly increasing eye pressure and the gradual loss of side vision. In medical term, eye pressure is called intraocular pressure (IOP). It is the fluid pressure inside the eye.

  2. Low-tension or normal-tension glaucoma. The optic nerve is damaged but the eye pressure is normal.

  3. Closed-angle glaucoma. This type produces a sudden increase in eye pressure. Symptoms include severe pain and nausea, as well as redness of the eye and blurred vision. This is a medical emergency and requires immediate treatment. Without treatment, blindness may occur in 1 or 2 days.

  4. Congenital glaucoma. This type affects children who are born with eye defects that slows the normal drainage of fluid. These children usually have obvious symptoms, such as cloudy eyes, sensitivity to light, and excessive tearing.

  5. Secondary glaucoma. This type develops as a complication of other medical conditions. It may be associated with eye surgery or advanced cataracts, eye injuries, certain eye tumors, or uveitis (eye inflammation). Pigmentary glaucoma occurs when pigment from the iris flakes off and blocks the meshwork, slowing fluid drainage. A severe form, called neovascular glaucoma, is linked to diabetes. Corticosteroid drugs used to treat eye inflammations and other diseases can trigger glaucoma in some people.

The following is focused on open-angle glaucoma.

Symptoms and Diagnosis

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 glaucoma remains untreated, people may miss objects to the side and out of the corner of their eye. Without treatment, people with glaucoma will slowly lose their peripheral (side) vision. They seem to be looking through a tunnel. Over time, straight-ahead vision may decrease until no vision remains.

Glaucoma can develop in one or both eyes.

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Normal vision

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By a person with glaucoma

 

Glaucoma is detected through a comprehensive eye exam that includes:

  1. Visual acuity test. This eye chart test measures how well you see at various distances.
  2. Visual field test. This test measures your side (peripheral) vision. It helps your eye care professional tell if you have lost side vision, a sign of glaucoma.
  3. Dilated eye exam. Pupil dilation provides eye care professional with a better view of the optic nerve to check for signs of damage. Drops are placed in your eyes to widen, or dilate, the pupils. After the exam, your close-up vision may remain blurred for several hours.
  4. Tonometry. The procedure to determine the IOP. There are many types of tonometry. The simplest but not very accurate type is called noncontact (or air-puff) tonometry which is often used to screen for high IOP.
  5. Pachymetry. A numbing drop is applied to your eye. Your eye care professional uses an ultrasonic wave instrument to measure the thickness of your cornea.

Causes

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In the front of the eye is a space called the anterior chamber. A clear fluid flows continuously in and out of the chamber and nourishes nearby tissues. The fluid leaves the chamber at the open angle where the cornea and iris meet. When the fluid reaches the angle, it flows through a spongy meshwork, like a drain, and leaves the eye.

Sometimes, when the fluid reaches the angle, it passes too slowly through the meshwork drain. As the fluid builds up, the pressure inside the eye rises to a level that may damage the optic nerve. When the optic nerve is damaged from increased pressure, open-angle glaucoma--and vision loss--may result. That's why controlling pressure inside the eye is important.

 

Reference:

National Eye Institute, USA.