During your routine eye exam, your optometrist will check your visual acuity. This term refers to the sharpness of your vision and how clearly you see objects. Using a Snellen Chart, your eye doctor will determine your visual range. This is measured by testing your eyes one at a time, while keeping the other covered.
So then what does 20/20 vision mean? Does that mean you have perfect vision? Technically there is no such thing as “perfect” vision, as there are several other factors that contribute to your visual capabilities, but it does mean that at 20ft away, you are seeing objects with the same clarity as the “average normal-sighted” person.
For example, if you were near-sighted and your optometrist told that you have 20/50 vision, it means that at 20ft away you can see what a person with 20/20 vision sees from 50ft away. On the flip side, some people have vision that is sharper than 20/20- like 20/15 or 20/10. In the same type example, that would mean that two people standing at the same distance from a sign, one with 20/20 can see clearly and the person with 20/10 can see clearly as well, but the latter can also see an additional 10ft past the sign.
Additional factors that contribute to your visual acuity are things such as your depth perception, ability to distinguish colors, peripheral vision and ability to focus on close objects. These are all things that your optometrist will check during your routine eye exam.