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
Tigers can see 6 times better at night than humans.
305
When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
132
Only about 2% of the world population has green eyes.
36
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
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75