The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
21
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
In ancient Egypt, priests plucked EVERY hair from their bodies, including their eyebrows and eyelashes.
130
Only about 2% of the world population has green eyes.
36
All humans have the ability to see ultraviolet light, but it is passively filtered out by the eye's lens. People who undergo surgery to remove the lens can detect ultraviolet light.
21