What is the name of the ‘system’ of vision?

Question

Someone says you have 20/40 vision, but how would you word a question when asking how good your vision is?

Would you say “How good is my vision on the ? scale?” and is there even a name for this system of classifying the quality of people’s vision.

Answer 1

That’s a test of visual acuity. The chart is known as the Snellen chart. It is sometimes called the Snellen test.