top of page
Search

What does 20/20 eyesight mean?

You might have heard at your eye exam that you have 20/20 vision (great!), but what exactly do those numbers mean?


The top number refers to the testing distance your vision is checked at: 20 feet. You might think, "But the exam room isn't that long!" Well, using optics and math, eye doctors can calculate a smaller (or larger) testing distance to fit in a smaller (or larger) exam room that is equivalent to using a 20 foot testing room. Essentially the testing chart letters are adjusted for size and placement.


The bottom number refers to what normally should be seen at a distance of 20 feet. For example, if your vision is 20/20 then you can see what should normally be seen at 20 feet. If your vision is 20/400, then you need to be 20 feet away from something that should normally be seen from a distance of 400 feet.

28 views0 comments

Recent Posts

See All

What causes dry eye?

Dry eye syndrome is a common condition that occurs when your eyes don't produce enough tears or when the quality of your tears is poor. This can lead to discomfort, irritation, and in severe cases, po

Can dry eye cause blurry vision?

Yes, dry eye can cause blurry vision. When your eyes are not properly lubricated due to insufficient tear production or rapid tear evaporation, the surface of the eye can become irregular or uneven. T

Can dry eye cause blindness?

Dry eye itself is not typically a direct cause of blindness. However, if left untreated or if the underlying causes are severe, it can lead to complications that might potentially affect vision. Dry e

bottom of page