What does it mean when scientists say “an eagle can see a rabbit in a field from a mile away”. Is their vision automatically more zoomed in? Do they have better than 20/20 vision? Is their vision just clearer?
In: Biology
Their vision is sharper. If you have good vision, you can probably easily spot a small crumb on a table several feet away, while to an old person, that image is more blurred and the crumb is simply not visible. Your vision is not “zoomed in” to see the crumb, it’s just sharper. Comparing the vision of a typical person to that of an older person, is similar to comparing an eagle’s vision to that of a typical person.
Bonus fact: 20/20 is not perfect vision, it’s typical human vision. It’s possible to have better than 20/20, e.g. 20/10 vision, which means you can see at 20 feet what a typical person can only see at 10 feet. Or if your vision was worse than average, say 20/40, you need to be 20 feet away to see something that a typical person can see from 40 feet away.
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