16 Crazy facts about human eyes that you probably didn’t know about

The human eye is an incredibly complex piece of natural machinery that processes images in color and it does so in ultimate high-definition.

You might think the eye performed a task with a simple process — the truth is far more complex than you could ever imagine.

Here are 16 amazing facts that show us just how incredibly eyes really are.

1. Your retinas see the world upside-down – Your brain flips the image. 

Upside Down Eyes

upload.wikimedia.org / wikicommons / Via quora.com

You can see how your eyes actually perceive the world if you look through a prism glass.

2. Images also show up on your retina split in half and distorted.

retina split in half and distorted

Your left and right brain each receive half of the image and then scramble the images together so you can see the entire photo.

3. Your retinas don’t detect the color red.

Color Red

Your eyes have red, green and blue color receptors, but the “red” receptor only detects yellow-green, and the “green” receptor detects blue-green. Your brain combined signals to turn them into red. 4. Your peripheral vision is low-resolution and nearly black-and-white.

Peripheral Vision

Your eyes “fill in” information before you notice that the resolution for your peripheral vision has been filled in.

5. Blue eyed people share a common ancestor with all other blue-eyed people in the world. 

Blue Eyed People

Blue eyes appeared as a mutation only 6,000 years ago.

6. Brown eyed people also come from a common ancestor — believed to be the first of our kind. 

Brown Eyes

You are rocking the original eye color.

7. Many blind people who were born with sight still have dreams in which they see images and colors. 

Dreaming and sight

8. The average person protected their eyes by blinking 17 times per minute. 


That might not seem like a lot but it’s equal to 14,280 times in a 14-hour day or 5.2 million times a year on average.

9. “20/20 vision” doesn’t mean you have perfect vision. It just means you see at 20 feet what the average person sees at 20 feet. 

2020 Vision

Glasses can correct your vision to 20/20 in many cases, but that’s just good enough to be average. Some high-tech solutions have recently emerged, such as contacts, that are meant to give humans better than 20/20 vision. 10. Shortsighted people have a longer than normal eyeball.


11. Farsighted people have a shorter than average eyeball.


12. Your eyeballs are nearly the same size now as they were when you were born. 

Baby Eyes

Babies are born with big heads that are not proportional to their body. Apparent that head is big enough to house almost fully grown eyeballs.

13. Babies can see clearly for about 15 inches. 

baby eyesight

That distance happens to be just about the right distance to see their mom’s face while breastfeeding.

14. Your tears have different compositions which change based on if something is irritating your eye, or you’re crying, or yawning.

Tear composition

The human eye really is an amazing piece of natural machinery.

15. Your eye makes constant jerking movements called “microsaccades” which stop objects from fading from your vision. 

Eye Movement

A process called Troxler’s phenomenon causes static objects in your gaze to disappear if you stare at them for too long (see image below). Microsaccades stop this from happening.

Eye Movement Example

16. The human eye can tell the difference between 50,000 shades of grey.


That’s a lot of grey.