From the Vision of Children Foundation:
From the moment you wake up to the moment your head hits the pillow again, your eyes are working. They go about with you day-to-day, absorbing as much information as possible to help you process your environment. Your eyes have been attached to you since birth, but there are probably a few things you did not know about them.
The most active muscle in the body is the eye.
As we mentioned above, your eyes are constantly working from the moment they open. They are providing constant information to the brain that you need to interpret the world. It only makes sense that the muscle in charge of such a lofty task is the most active. This does not make it the strongest, but it can only do so much.
Your iris is a great deal more unique than your fingerprint.
The fingerprint, with its 40 different characteristics, is undoubtedly unique to its person, but the iris pattern is so unique and intricate that even identical twins differ in that aspect. The iris has a whopping 256 unique mapping characteristics. This large difference in uniqueness is why there is a push towards retina scanning security devices over fingerprint scanners.
The normal adult blinks 15-20 times a minute on average.
Some research shows that this is more than just to provide lubrication to the eyes. According to research done at Osaka University in Japan, some of these blinks may allow the brain to rest, even if only for half a second.
Your eyes contain 7 million cones and 100 million rods.
Cones help you see details and color while rods help you see in low lighting. Rods are not used to discern color. They are used to take in shapes, black, white, and grey.
The human eye only sees three colors.
Thanks to the cones in our eyes, we can process the red, green, and blue wavelengths to develop different colors. When light hits an object, the object absorbs some of the light and reflects back the rest. This is where some of the red, green, and blue wavelengths are absorbed and reflected back to show a certain color.