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) Another test uses a special device (in conjunction with eye-numbing drops) to “touch” the surface of the eye to measure eye pressure.
While increased eye pressure is a key indicator of the disease, it does not necessarily mean you have a glaucoma diagnosis. In fact, the only way to detect glaucoma is to have a detailed, comprehensive eye exam that often includes dilation of the pupils.
So “true” glaucoma testing actually involves examining the retina and optic nerve at the back of the eye for signs of the disease.
Glaucoma can cause slight to severe vision loss, and is often discovered only after the disease is present—that’s why glaucoma testing is so important.
Ask the Doctor about Glaucoma:
If Glaucoma is caused by increased pressure in the eyes, wouldn’t I feel if I had it?
Unfortunately, No. Glaucoma is known as the “silent thief of sight”, and in most cases is completely painless. In fact, it typically shows no symptoms until it is very late-stage. Initially it will cause a patchy peripheral vision loss - and because your brain can fill in the gaps, it often goes unnoticed until the loss becomes more profound. The optic nerve is like a fibre optic cable - there are over a million nerve fibres that transmit information from the eye to the brain. Once damage is done to the optic nerve, it is permanent and irreversible. That is why it is important to have routine eye health exams by your Doctor of Optometry. Optometrists can detect early warning signs of glaucoma, and monitor you more closely if you have any risk factors. Fortunately with early detection, glaucoma can be treated and severe vision loss can be avoided.