During a vision test, what does the numerator of 20 in visual acuity signify?

In a vision test, the numerator of 20 refers to the distance in feet from which the client is standing when they are being tested on the eye chart. This distance is standardized at 20 feet, which is the distance most commonly used for visual acuity assessments.

The significance of this measurement lies in its role in determining how well a person can see at that distance compared to someone with normal vision. For instance, if a client reads the same line on the eye chart that a person with normal vision can read from 20 feet away, then their visual acuity is recorded as 20/20. If a client can only read what a person with normal vision can read at a distance of, say, 60 feet when they are at 20 feet, their vision might be recorded as 20/60. This method of assessing vision allows healthcare providers to determine the clarity of a person’s vision in comparison to the standard for what is considered normal.