Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
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
The human eye blinks an average of 4,200,000 times a year.
233
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
The colossal squid has the largest eyes in the world.
4
Poor eyesight (myopia) is associated with higher IQ.
232
Tigers can see 6 times better at night than humans.
305