Ever wonder why your eye doctor performs so many tests? No, they are not all just checking to see if your prescription has changed. Some of those tests check for specific, eye-related diseases; if left untreated, these diseases can cause impairment or even loss of vision. While not a complete list of tests that your eye doctor performs, the tests below can shed some light on the matter during your next eye exam.
The Eye Chart
The eye chart is something you have looked at since you first had an eye exam. In more modern offices, the eye chart is projected onto a screen. In some, old-school offices, there is a physical eye chart on the wall. The point is to assess the smallest line that you can read correctly.
Often, this test is combined with the "paddle" test, in which you cover one eye at a time with the paddle and read the smallest row you can on the eye chart. Your total vision with both eyes can mask the weakness in one eye.
Individual Eye Vision Test
In this test, your doctor will have you look into a contraption that has a number of different "lenses" that he or she can change. He will test one eye at a time and seem to continually ask you whether "A or B", "1 or 2", etc., is better. As you answer, your doctor, can zero in on the best measure of the vision capabilities for each eye.
If you already wear contacts or have glasses, your eye doctor will start from your base prescription and make changes.
You may not always take this test. If you have gone to the same doctor for some time, it is likely that your color vision has not changed significantly. However, if you have not been tested before or start with a new doctor, you may be asked to look at some special cards that have numbers made up of colored dots. If you have trouble seeing the number, or can't see it at all, then you have a problem with your color vision.
This is one of the tests that actually checks for glaucoma, a disease that causes pressure to build within the eye and can lead to vision loss. The most common version, nowadays, is to jet a small puff of air at the eye to measure the pressure.
Dilating the eyes, while mildly unpleasant, allows your doctor to check for other eye conditions. Your doctor can check for swelling or leaking blood vessels, age-related macular degeneration, or issues with the optic disc where the optic nerve fibers exit the eye and enter the brain.
Now, you should have a solid understanding of standard eye tests. Next time you see an eye doctor like those at the Montgomery Eye Center, you can ask him what he sees in your eyes!