The purpose of screening is early diagnosis and treatment. Screening tests are given to people without current symptoms, but who may be at high risk for certain diseases or conditions. Since glaucoma usually has no symptoms and can occur in anybody regardless of risk factors, screening may detect the condition early and prevent visual loss. However, screening everyone is controversial as early identification and treatment of glaucoma in patients without symptoms has not been shown to prevent significant visual loss. You should talk to your doctor to see if you would be more likely to benefit from screening.

Screening Guidelines

The American Academy of Ophthalmology recommends the following for all patients, even if you do not have eye problems or are not at risk for eye disease:

  • A baseline eye exam at age 40
  • Between the ages of 40-54, later exams should occur every 2-4 years
  • Between the ages of 55-64, later exams should occur every 1-3 years
  • At age 65, a complete eye exam should occur every 1-2 years

Based on the results of the exam, your doctor will recommend a treatment plan and/or a schedule for follow-up visits.

You may need more frequent visits if you:

  • Currently have an eye condition
  • Have symptoms of an eye condition
  • Are at an increased risk for an eye condition
  • Have a chronic disease that may affect your vision, such as diabetes or high blood pressure
  • Wear contact lenses

The eye exam also tests for other eye disorders, such as cataracts and macular degeneration .

If you currently have eye symptoms, you should call your provider immediately for an evaluation. In case of an emergency, call for emergency medical services right away.

Screening Tests

During your eye exam, your eye care professional may do the following tests:

Visual acuity —This test measures how well you see at various distances. You will be asked to look at a chart of letters or numbers and identify what you see.

Tonometry —This test measures the pressure inside the eye. There are several types of tonometry. In air tonometry, a puff of air is blown onto the cornea to take the measurement. Another type uses a small plastic device (Goldman tonometer) that lightly pushes against your eye to measure your intraocular pressure. For this test, the eye is first numbed with an eye drop, so you do not feel anything.

Gonioscopy —The eye care professional can see the drainage angle of your eye using a special lens.

Pupil dilation —Drops are put in your eyes that enlarge/dilate your pupils. This allows the eye care professional to see more of the inside of your eye. Your close-up (near) vision may remain blurred for several hours afterwards and you may be sensitive to bright light. Ask for a pair of sunglasses after the dilation.

Ophthalmoscopy —Once your pupils are dilated, the eye care professional will examine your optic nerve and the rest of your retina with an instrument called an ophthalmoscope. The color and appearance of the optic nerve may indicate if damage from glaucoma is present and how extensive it is. Pictures of your optic nerve will likely be taken for future comparison.

Perimetry (visual field test) —This test produces a map of the complete field of vision. It is used to check whether there is damage to any area of vision. Since glaucoma slowly affects your peripheral, or side vision, you may not know you have any problems until detected on this test.

Pachymetry —The thickness of your cornea may be measured using a special machine called a corneal pachymeter. Your eye is numbed with a drop first and it does not hurt.

Nerve fiber layer analysis —A special machine, such as an OCT, GDx, or HRT, may be used to measure the thickness of your optic nerve. This can often be compared to normative data from other people without glaucoma of your age, sex, and race. It also can be rechecked in the future to see if there is any loss of nerve fiber thickness with time.

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