The human eye blinks an average of 4,200,000 times a year.
233
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Only about 2% of the world population has green eyes.
36
Poor eyesight (myopia) is associated with higher IQ.
232
Tigers can see 6 times better at night than humans.
305
The colossal squid has the largest eyes in the world.
4
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.
22