Glaucoma

What is glaucoma?

Glaucoma is a disease of the optic nerve, the part of the eye that carries images to the brain. The optic nerve is made up of many nerve fibers. When pressure inside the eye increases, damage to the optic nerve fibers may occur, causing blind spots to develop. These blind spots usually go undetected until the optic nerve is significantly damaged. If the entire nerve is destroyed, blindness results.

What causes glaucoma?

Clear liquid, the aqueous humor, normally circulates inside the front portion of the eye. A small amount of the aqueous humor is produced constantly, replacing an equal amount that flows out of the eye through a microscopic drainage system, thereby maintaining a constant level of pressure in the eye.

The eye is a closed structure and if the drainage area for the aqueous humor, the drainage angle, is blocked, then the excess fluid cannot flow out. Fluid pressure will then increase in the eye, pushing against the optic nerve and potentially causing damage.

What are the different types of glaucoma?

Chronic open-angle glaucoma is the most common form of glaucoma in the U.S. The risk of developing chronic open-angle glaucoma increases with age. The drainage angle of the eye becomes less efficient over time and pressure within the eye gradually increases, which can damage the optic nerve. Chronic open-angle glaucoma damages vision so gradually and painlessly that you are normally not aware of trouble until the optic nerve is already damaged.

Angle-closure glaucoma. Sometimes the eye's drainage angle becomes completely blocked. In the eye, the iris may drop over and completely close off the drainage angle.

When eye pressure builds up suddenly, an acute angle-closure glaucoma attack occurs. Symptoms may include:

• blurred vision;
  
• severe eye pain;
  
• headache;
  
• rainbow-colored halos around lights;
  
• nausea and vomiting.

This is a true emergency! If you experience any of these symptoms, call your ophthalmologist immediately. If this type of glaucoma is not treated quickly, blindness can result.

What are the risk factors?

The most important risk factors include:

• age;
  
• family history of glaucoma;
  
• African ancestry;
  
• past eye injuries.

If any of these risks apply to you, you should have regular examinations to detect the early signs of damage to the optic nerve.

How is glaucoma treated?

Treatment includes any of the following:

• Medications
  
• Laser surgery
  
• Surgery in the operating room

Further loss of vision may be prevented by having regular eye examinations and by following your doctor's instructions.