The only way to determine whether you have glaucoma is to have an eye doctor test your vision and examine your eyes.
You may be tested for glaucoma even if you are not experiencing any symptoms. For example, if you are at a heightened risk of glaucoma because of your age or ethnic background, your doctor may recommend testing for glaucoma during a routine eye exam appointment.
Eye doctors have a range of tests and tools to aid them in this diagnostic process. The technology is advanced and the tests are painless and non-invasive.
If your doctor suspects you have glaucoma, one of the first things they will do is test your intraocular pressure using tonometry. During the test, your eyes are numbed and either a special probe-like device called a tonometer or a gentle puff of air is used to press on your cornea. This does not hurt. The pressure with which your cornea pushes back against the probe or air is measured in millimeters of mercury (mm Hg). A healthy intraocular pressure ranges from 12 to 22 mm Hg.
Visual Field Test
The doctor will want to test your visual field to determine whether you have lost any vision. A visual field test involves looking at the center of a bowl-shaped instrument called a perimeter, with one eye covered. You will start to see small lights through the perimeter. Whenever you see a light, you press a button. The lights appear in different areas of the visual field and at different intensities to help the doctor determine whether you have any vision loss outside of your central visual field, and to measure how sensitive your eyes are.
In glaucoma, it is usually side vision that suffers. As the disease progresses, the visual field gets narrower.
Optic Nerve Exam
Another key part of diagnosing glaucoma is examining the optic nerve for signs of damage. To do this, the eyes are dilated and the doctor holds an instrument called an ophthalmoscope close to the eye to look through the pupil and observe the shape and color of the optic nerve.
If the optic nerve has lost its healthy pink color or appears to have damage known as “cupping,” it indicates a potential problem. When looking at a healthy optic nerve, it looks similar to a cup seen from above. There is a small empty space in the middle of the nerve surrounded by many optic nerve fibers. But glaucoma causes nerve fibers to die off, which makes the cup appear to get bigger as the remaining nerve fibers occupy less space.
What Else Does the Doctor Check?
Other exams and tests that can be performed to help your doctor confirm or rule out glaucoma include the following:
- A visual acuity test using a standard reading chart
- A slit-lamp exam to get a magnified view of the general structures and mechanics of your eyes
- Gonioscopy to inspect the drainage angle and determine whether it is wide or narrow
How Often Should You Be Screened for Glaucoma?
Catching glaucoma in its early stages offers the best chances of properly managing the disease and staving off related vision loss. And the best way to catch glaucoma early is with regular eye exams — even in the absence of any noticeable symptoms.
Before the age of 65, you should have your eyes tested at least every two years; after the age of 65, you should see an eye doctor every six months to a year for an exam. If you have risk factors for glaucoma, your doctor may recommend more frequent exams.
For more information about glaucoma and how it is diagnosed, please speak with your eye doctor or contact Guardion Health Sciences.