20 Wacky Facts About the Human Eyeball

It’s National Eye Health Month – can you read this okay?


Yes parents, if you can read this without corrective help, hallelujah! There’s something about raising kids and getting older that can really take a toll on the ol’ peepers. If you find yourself straining to see street signs, or read, it’s time to take a trip to the opthamologist.

And in the meantime, here is some quirky trivia about the human eye.


  1. Eyes (of any sort) may have begun to develop 550 million years ago. The eye started out as patches of photoreceptor protein in single-celled organisms.
  2. The visible spectrum for humans falls between ultraviolet light and red light. Scientists estimate that humans can distinguish up to 10 million colors.
  3. The average blink lasts for about 1/10th of a second and you blink about 12 times every minute.
  4. Your eyes start to form in the womb two weeks after you are conceived.
  5. There is no way to transplant an eyeball. The optic nerve that connects the eye to the brain is too sensitive to reconstruct – so far. Maybe the robots will be better at it than we are.
  6. Some people are born with two differently colored eyes. This condition is heterochromia.
  7. Your eyeballs stay the same size from birth to death. Maybe that’s why babies eyes look so huge – they are!
  8. Your vision literally has a blind spot! Each of your eyes has a small blind spot in the back of the retina where the optic nerve attaches. You don’t notice the hole in your vision because your eyes work together to fill in each other’s blind spot, but if you stare directly at a star, you can’t see it, where if you look just to the side, you can see it much more clearly.
  9. An eye is composed of more than 2 million working parts and is the most active muscle in the body. Even when we sleep, it’s still working!
  10. Only 1/6 of the human eyeball is exposed.
  11. Corneas are the only tissues in the body that don’t have blood.
  12. 80% of our memories are determined by what we see.
  13. Eyes heal quickly. With proper care, it takes only about 48 hours to repair a minor corneal scratch.
  14. There are about 39 million people that are blind around the world.
  15. 80% of vision problems worldwide are avoidable or even curable.
  16. Humans and dogs are the only species known to seek visual cues from another individual’s eyes, and dogs only do this when interacting with humans.
  17. A fingerprint has 40 unique characteristics, but an iris has 256, making retina scans a more precise security measure.
  18. “Red eye” occurs in photos because light from the flash bounces off the back of the eye. The choroid is located behind the retina and is rich in blood vessels, which make it appear red on film.
  19. 80% of what we learn is through our eyes.
  20. Eyes are the second most complex organ after the brain.


Tada! The human is pretty impressive, and now that we’re done appreciating it, make sure you and your family get your eyes checked regularly. Good looking out!





  1. https://www.aao.org/eye-health/tips-prevention/how-humans-see-in-color
  2. http://discoveryeye.org/20-facts-about-the-amazing-eye/

About Susie Almaneih

Susie Almaneih spent several years during her young adulthood teaching children dance at her church group, as well as other cultural-based activities. Susie now spends as much time as she can giving back to the families in her community. Over the years, this love for community has evolved into a deeper love for delivering positive and creative content and awareness to families of all ages.

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