Everything You Never Knew About Your Eyes

Your eyes are probably something you don't think about often. Your eyes are there doing their job, but you don't have to use any excess effort to use them, so they don't generally come to mind. You may not realize how amazing your eyes truly are. Here are some fascinating facts about your eyes that you probably didn't know about.

Eye Color

  • Heterochromia is a genetic mutation that causes different colored eyes.
  • Complete heterochromia gives someone different colored eyes, while central and sectoral heterochromia gives a single eye more than one color.
  • Blue eyes are a result of a melanin and lipochrome deficiency.
  • All humans had brown eyes at one point.
  • Only 2% of the world's population has green eyes.


  • About 10% of people are color blind.
  • Color blindness is caused by a loss of the light responsive chemical in your photoreceptors.
  • A total loss of the light responsive chemical would cause you to see everything as black and grey.
  • 20/20 vision means you can see items 20 feet in front of you as well as the average person.
  • Humans have three different types of cones in the eye that allow them to perceive color.
  • Tetrachromacy is a condition where a person is born with a fourth type of cone to see colors no one else can see. Tetrachromacy is rare and so far only found in women.


  • A scratch on the eye can heal in about 48 hours. Glaucoma is an umbrella term for a group of diseases that damage the optic nerve in the eye.
  • About 2% of Americans over age 40 have glaucoma.
  • About 80% of eye problems are curable and avoidable.
  • Corneas don't carry blood like every other human tissue.
  • Eyebrows protect your eyes from sweat.


  • Most people blink about 12 times every minute.
  • Each blink lasts about .1 second.
  • Contrary to popular belief, eyeballs DO grow. They grow slowly from birth until you're about 16 years old. The total change is about 8 millimeters.
  • Eyes see things upside down, and your brain flips the images the right way.
  • Babies don't produce tears until they're one to two months old.
  • Eyes contain more than 100 million cells.
  • Your eyelashes have a life span of about 5 months before you shed them.
  • If you lined up all of the eyelashes you've ever produced, they'd total nearly 100 feet long.
  • An iris has 256 unique characteristics. That is 216 more than a fingerprint.

The human eye is a fascinating thing, which is why it should be cared for by professionals, like those at Whiteville Eye Associates. Every human eye is different from another, yet they're all made generally the same way. Whether you have brown or blue eyes, or even a fourth type of cone, these facts pertain to you.