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
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
Shark corneas are used in eye transplants and shark bone marrow can be used to graft human bones.
132
Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
Our eyes are always the same size from birth, but our nose and ears never stop growing.
266
Only about 2% of the world population has green eyes.
36