The term “15/20 vision” refers to a measurement of visual acuity, which indicates how well a person can see compared to a standard. The fraction is derived from a standardized eye chart test, usually conducted at a distance of 20 feet.
Here’s a breakdown of what “15/20 vision” means:
The first number (15) represents the distance in feet at which a person with normal vision can see the same detail that a person with 20/20 vision can see at 20 feet. In other words, if you have 15/20 vision, you can see at 15 feet what a person with normal vision (20/20) can see at 20 feet.
The second number (20) is the standard reference for normal vision, which is considered to be the ability to see clearly at a distance of 20 feet.
In practical terms, having 15/20 vision means that your eyesight is slightly worse than average. A person with 20/20 vision can see more detail at a greater distance than someone with 15/20 vision. However, 15/20 vision is still generally considered to be quite good, as it indicates that a person can see fairly well, though not quite at the level of perfect vision.