What Is a Glaucoma Test?
Glaucoma is the generalized name for a group of eye diseases that damage the optic nerve of the eye, preventing the eye from sending accurate visual information to the brain. Glaucoma tests are designed to test your eyes for one of the key symptoms of the disease—increased eye pressure—however only a comprehensive eye exam can reveal whether or not you have glaucoma. Increased pressure inside the eye is often a key indicator of glaucoma, though not exclusively so. Eye doctors can use a number of tests for eye pressure, but will, by default, check for signs of glaucoma as part of a detailed examination of the retina—the light sensitive area at the back of the eye responsible for processing images.
How Does Glaucoma Testing Work?
A glaucoma test is usually part of a routine eye exam. Both types of glaucoma tests measure internal pressure of the eye.
One glaucoma test involves measuring what happens when a puff of air is blown across the surface of the eye. (A puff test). We prefer a different way to measure eye pressure. We use an instrument called an applanation tonometer, which is usually attached to a slit lamp. For this test, a yellow eye drop is placed on your eyes. Your eyes will feel slightly heavy when the drops start working. This is not a dilating drop – it is simply a numbing agent combined with a yellow dye. Then the technician or doctor will have you stare straight ahead in the slit lamp while he or she gently rests the bright-blue glowing probe of the tonometer on the front of each eye and manually measures the intraocular pressure. Both tests are painless and take just a few seconds.