Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
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
Sheep, goats, octopuses, and toads have rectangular pupils.
7
Poor eyesight (myopia) is associated with higher IQ.
232
Only about 2% of the world population has green eyes.
36
When you are looking at someone you love, your pupils dilate, they do the same when you are looking at someone you hate.
1k
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