You have most likely stumbled upon the terms visual acuity and twenty-twenty vision. Still though, what do these terms truly mean? When you understand these terms, you will see why an eye doctor asks to assess more than just how well you read the eye chart.
The term 20/20 vision is used to indicate the clarity and sharpness of vision from 20 feet away. If you've been told you have 20/20 eyesight, it means that from a distance of 20 feet you're able to accurately see that which should be seen from that distance. So, 20/100 eyesight would indicate that you would need to be as close as 20 feet away to see what a normal-sighted person is able to see from 100 feet away.
Both eyes are examined one after the other. When the optometrist asks you to read the letters on the eye chart, the smallest letters you can clearly see determine the visual acuity in the eye being tested.
It's important to recognize that 20/20 vision doesn't always mean that your eyesight is flawless, because it can only judge how good your eyesight is at a distance. There are several other necessary components to seeing well; your ability to focus on close objects, contrast sensitivity, peripheral awareness, depth perception, eye coordination and color vision – these are aspects of healthy vision. More importantly, someone who has 20/20 vision can certainly have eye problems. People with damage to the sensory nerves inside their eyes as a result of glaucoma, diabetes, high blood pressure, or other diseases might still have 20/20 vision without needing to wear eye glasses. For this reason, your eye care professional should always perform a comprehensive eye exam, as opposed to just a regular visual acuity exam.
The next time you book yourself in for a comprehensive eye exam, you'll understand what we're testing for when we ask you to read letters from an eye chart!
We are also a great choice for anyone looking for an optometrist in Canton for visual acuity eye exams.