Question

what does 40% eyesight means? (in power)​

Answer 1

Explanation:

Vision Testing

Visual acuity is usually measured with a Snellen chart. Snellen charts display letters of progressively smaller size. ... 20/40 vision means that the test subject sees at 20 feet what a person with normal vision sees at 40 feet.

Answer 2

Answer:

Normal" vision is 20/20. ... 20/40 vision means that the test subject sees at 20 feet what a person with normal vision sees at 40 feet.

Explanation:

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