Glaucoma Screening & Diagnosis
On this page, you will find the following:
Diagnosis of Glaucoma
Individuals at high risk for glaucoma should have a dilated pupil eye examination at least every two years. Eye doctors use several tests to detect glaucoma; these tests include:
Tonometry measures the pressure inside the eye. Examples of tonometers include: 1) The air puff or noncontact tonometer emits a puff of air. Eye pressure is measured by the eye's resistance to the air. 2) The applanation tonometer touches the eye's surface after the eye has been numbed, and measures the amount of pressure necessary to flatten the cornea. This is the most sensitive tonometer, but a clear, regularly-shaped, cornea is needed for it to function properly. 3) The electronic indentation method measures pressure by directly contacting anesthetized eyes with a digital pen-like instrument.
In pupil dilation, special drops temporarily enlarge the pupil so that the doctor can better view the inside of the eye.
Visual field testing measures the entire area seen by the forward-looking eye to document straight-ahead (central) and/or side (peripheral) vision. It measures the dimmest light seen at each spot tested. Each time a flash of light is perceived, the patient responds by pressing a button.
A visual acuity test measures sight at various distances. While seated 20 feet from an eye chart, the patient is asked to read standardized visual charts with each eye, with and without corrective lenses.
Pachymetry uses an ultrasonic wave instrument to help determine the thickness of the cornea and better evaluate eye pressure.
Ophthalmoscopy allows the doctor to examine the interior of the eye by looking through the pupil with a special instrument. This can help detect damage to the optic nerve caused by glaucoma.
Gonioscopy allows the doctor to view the front part of the eye (anterior chamber) to determine if the iris is closer than normal to the back of the cornea. This test can help diagnose closed-angle glaucoma.
Optic nerve imaging helps document optic nerve changes over time. Nerve imaging techniques include stereo optic nerve photographs, scanning laser polarimetry (GDx), confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph or HRT) and optical coherence tomography (OCT). All four techniques are painless and non-invasive. A doctor will determine which method(s) to use.
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Find a Doctor
The following "Find a Doctor" resources may be helpful in locating an eye care professional:
It is very important to have regular eye examinations, particularly as you age, or if you have any of the risk factors associated with glaucoma. Glaucoma normally has no symptoms until vision that cannot be regained is lost. However, if diagnosed early, glaucoma is treatable. Eye pressure can be monitored and controlled, and disease progress can be delayed. People under age 60 should have an eye exam at least every two years; for those over age 60 or at risk, a physician may recommend more frequent exams.
Both optometrists and ophthalmologists can be eye doctors, but the two degrees reflect different levels of training.
- An optometrist has an undergraduate degree followed by four years of optometry school and is a Doctor of Optometry (OD). An optometrist is an eye doctor who examines patients to make certain they can see well, their eyes work properly together and are healthy and free of disease. They diagnose, manage and treat vision problems and eye diseases.
- An ophthalmologist has an undergraduate degree followed by four years of medical school, one year of internship, and three years of ophthalmology residency and is a Doctor of Medicine (MD). An ophthalmologist is an eye doctor who can also perform eye surgery.
Though both of these types of providers have made their careers taking care of our vision, we live in a specialized society and some eye doctors may not be as equipped or prepared to properly detect and manage glaucoma as another eye doctor. This is true of both optometrists and ophthalmologists. Your eyesight is very important. Since not all communities will have eye care providers, travel may be required to obtain appropriate care. Ask questions before making an appointment. For people with advanced glaucoma, an ophthalmologic glaucoma specialist may be needed. Ask your eye doctor who they recommend so that you receive the best possible care.
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The following BrightFocus publications provide more information:
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Disclaimer: The information provided is a public service of the BrightFocus Foundation and is not intended to constitute medical advice. It should not in any way substitute for the advice of a qualified healthcare professional. Please consult your physician for personalized medical advice; all medications and supplements should only be taken under medical supervision. BrightFocus Foundation does not endorse any medical product or therapy.
Source: BrightFocus Foundation is grateful to Carla J. Siegfried, M.D. at Washington University in St. Louis, Missouri for reviewing aspects of the above content.
Last Review: 04/28/13