Screening for Glaucoma
The purpose of screening is early diagnosis and treatment. Screening tests are usually administered 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, everybody should be screened for the disease as recommended by their physician.
Regular eye exams by an eye care professional are the best way to screen for glaucoma. Because most people experience no symptoms with glaucoma, it is important to schedule a regular eye exam. The frequency depends on your age, risk factors, and general health. See the screening guidelines below.
During your eye exam, your eye care professional may do the following tests:
—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.
—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 in order to measure your intraocular pressure. For this test, the eye is first numbed with an eye drop, so you do not feel anything.
—The eye care professional can see the drainage angle of your eye using a special lens. This can help determine if you are at risk for closed-angle glaucoma.
—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 your doctor for a pair of sunglasses after the dilation.
—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.
Your doctor will probably take pictures of your optic nerve 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.
—Your physician may measure the thickness of your cornea 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
—Your doctor may use a special machine, such as an OCT, GDx, or HRT, to measure the thickness of the nerve fiber around 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.
The American Academy of Ophthalmology recommends the following:
- One complete eye exam in your 20s.
- Two complete eye exams in your 30s.
- A baseline eye exam at age 40, even if you have no eye problems or are not at risk for eye disease.
- A complete eye exam after age 65 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.
Cautionary Note: If you currently have eye symptoms, you should call your provider immediately for an evaluation.
In case of an emergency, call for medical help right away.
Facts about glaucoma.
National Eye Institute
website. Available at:
http://www.nei.nih.gov/health/glaucoma/glaucoma%5Ffacts.asp. Accessed July 16, 2013.
Friedman DS, Wolfs RC, et al. Prevalence of open-angle glaucoma among adults in the United States.
Open-angle glaucoma. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed/what. Updated June 6, 2013. Accessed July 16, 2013.
Vision screening recommendations for adults 40 to 60. American Academy of Ophthalmology Eye Smart website. Available at:
http://www.geteyesmart.org/eyesmart/living/midlife-adults-screening.cfm. Accessed July 16, 2013.
Vision screening recommendations for adults over 60. American Academy of Ophthalmology Eye Smart website. Available at:
http://www.geteyesmart.org/eyesmart/living/seniors-screening.cfm. Accessed July 16, 2013.
Vision screening recommendations for adults under 40. American Academy of Ophthalmology Eye Smart website. Available at:
http://www.geteyesmart.org/eyesmart/living/young-adults-screening.cfm. Accessed July 16, 2013.
Weinreb RN, Khaw PT. Primary open-angle glaucoma.
What is glaucoma? American Academy of Ophthalmology website. Available at:
http://www.geteyesmart.org/eyesmart/diseases/glaucoma.cfm. Accessed July 16, 2013.
What is glaucoma? Glaucoma Research Foundation website. Available at:
http://www.glaucoma.org/glaucoma. Accessed July 16, 2013.