What are the tests for glaucoma?

Eye tests are not just about getting glasses. They are an important health check.

A routine test may begin with checking for normal eye movement and the familiar eye chart. The eye chart is a visual acuity test - a test of how much detail you can see. This will also detect whether wearing glasses or changing lenses could help improve your eyesight. But these tests will not detect glaucoma.

To check for glaucoma, your optician should conduct at least three tests, checking the pressure in the eye, the visual field and the optic nerve. The optician can do these in a number of ways.

The pressure within the eye can be tested using a special instrument called a tonometer (See example to left). Although there are different types of tonometers, in most cases, a short puff of air is aimed at the eyeball. Remember that if the result is normal, you may still have glaucoma.

A visual field test examines the condition of your vision. During the test you will be asked to keep staring at a single point on a screen. While you keep your eye still, spots of light will appear on different parts of the screen. All you have to do is indicate when you see one. This test can help to detect glaucoma and other problems.

The ophthalmoscope is used to look at the eye in great detail. This allows the optician to see the retina and the optic nerve. Special eye drops may be needed that make your pupils dilate so that optician can see more clearly. These drops may make your vision blurry. You should not drive or use heavy machinery for a few hours after the drops.