why is 20/20 vision considered the standard for good vision? How does the eye differ when people have 20/10 vs 20/200?

Question

why is 20/20 vision considered the standard for good vision? How does the eye differ when people have 20/10 vs 20/200?

In: Biology

Answer 1

Both numbers in 20/20 have meaning. They mean “You can see this from 20 feet away”/”people with normal sight can see this from 20 feet away.” so basically you match up with the expected average

if someone has 20/10 vision, their eyesight is twice as good as the average because everyone else needs to get much closer to see things. If someone have 20/200 vision, that’s the bar for being declared legally blind because you need to practically be right next to something compared to people seeing it clearly from across the room