How Is Glaucoma Diagnosed?

Find out how glaucoma is diagnosed. Early detection can prevent blindness in most cases.

Although glaucoma can produce symptoms, the best way to detect the disease is by having regular eye examinations. Early detection and treatment can prevent blindness in 90 percent of people with glaucoma.

Symptoms of open-angle glaucoma
Open-angle glaucoma, the most common form of the disease, does not have symptoms at first. Vision is normal and there is no pain. If the disease is not treated, however, vision can become blurry and side vision might be lost. You may feel you are looking through a tunnel. Over time, your remaining forward vision may decrease until no vision remains.

Symptoms of angle-closure glaucoma
Angle-closure glaucoma can cause a sudden increase in eye pressure (acute glaucoma), which is a medical emergency. If it occurs, seek treatment immediately. Symptoms include:

  • Redness and swelling
  • Blurred vision
  • Severe eye pain
  • Headache
  • Rainbow-colored halos around lights
  • Nausea and vomiting
  • A red eye with a cloudy center
  • Pain around eyes after watching TV or leaving a dark theater

Tests for glaucoma
Regular eye examinations include testing for glaucoma. The following are standard:

  • A standard eye chart measures how well you see at various distances.
  • A visual field test measures your side (peripheral) vision. In computerized visual field testing, you are asked to push a button each time you see a flash of light. Your doctor will then receive a printout of your visual field. In another test (Goldmann perimeter), the doctor records your answers, and no computer is used.
  • A tonometer measures the pressure inside the eye. In one type (applanation tonometry), your doctor first inserts eye drops to reduce pain. A plastic prism will then lightly push against your eye to measure the pressure. In air tonometry, a puff of air is applied to the cornea. The eye's resistance to the air is measured to determine eye pressure.
  • An ophthalmoscope enables your doctor to look at the optic nerve through the pupil of your eye. The color and appearance of the nerve can indicate damage from glaucoma. Before the test is done, eye drops will be applied to dilate (widen) the pupil. After the examination, your close-up vision may remain blurred for several hours, and your eyes will be more sensitive to light.