What is visual acuity?

Visual acuity is the term used to describe the clarity or sharpness of vision. When your visual acuity measurement is 20/20 for example, it means you can see clearly at 20 ft. what should normally be seen at that distance.

How we measure visual acuity

The Snellen Eye Chart – developed in 1862 by Dutch ophthalmologist Herman Snellen – helps measure your eye’s acuity.

What does 20/20 vision look like?

20/20 vision is often described as “perfect” eyesight—but it’s only a reflection of the sharpness or clarity of vision at that distance. Sometimes, people see well from a distance but have trouble with near vision (due to presbyopia or hyperopia, for example). Or, their vision maybe be blurry due to a cataract. So, having 20/20 vision does not always signify perfect eyesight.

20/10 vision

20/10 vision is above-average vision, and means that what you see at 20 ft. is what the average person sees at 10 ft. You’ve got extra precise and accurate vision—lucky you!

20/40 vision

20/40 vision means you can only see as well as what a normal person can see at 40 feet away. You may notice some blurriness at this stage and may require some form of vision correction.

20/200 vision

For comparison, if you have 20/200 vision then you must be as close as 20 ft. to see what the average person sees at 200 ft.