When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
There are glasses which allow a red-green color-blind person to see colors the way everyone else does.
22
Tigers can see 6 times better at night than humans.
305
The human eye blinks an average of 4,200,000 times a year.
233
The colossal squid has the largest eyes in the world.
4
Poor eyesight (myopia) is associated with higher IQ.
232
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
There's a woman named Veronica Seider who had vision 20x better than average. She could identify people more than a mile (1.6km) away.
22