09 Feb 30 amazing facts about your eyes!
Eyes are an amazing part of the human body, but I bet you don’t know how incredible they really are! Here are 30 astonishing facts about eyes that will make you appreciate your peepers even more!
- The most common eye colour in the world is brown, with over 55% of the world’s population having brown eyes.
- Every human in the world is born colour-blind! At birth, babies can only see in black, white and some shades of grey, because certain nerve cells in their retina and brain are not fully developed. However, they develop the ability to see in full colour within a week.
- Dog’s eyes can’t distinguish between red and green, so keep that in mind next time you play fetch!
- Human eyes are not the most highly evolved in the animal kingdom. The eyes of a mantis shrimp have four times as many colour receptors as humans, some of which can see ultraviolet.1
- Our peripheral vision is very low-resolution and picks up visuals in nearly complete black and white.
- The cornea is the only tissue in the human body which doesn’t contain blood vessels. The cornea must remain clear in order to refract light correctly. If blood vessels were present, they would interfere with this process.
- Our eyes can process over 36,000 bits of information to our brain, every hour!
- 1/10th of a second is the average length of a blink, so ‘the blink of an eye’ is very quick indeed! It is even possible to blink 5 times in one second! 2
- Having two eyeballs is what gives us depth perception – comparing two images allows us to determine how far away an object is from us.
- We actually see things upside down and our brain turns the image the correct way up. As a result of having a curved cornea, the light that enters our eyes is refracted and creates an upside down image on the retina. 1
- An ostrich’s eye is bigger than its brain.
- Eyelashes and Eyebrows aren’t just there to look good! Eyelashes act as dust and dirt catchers to stop irritants getting into our sensitive eyes and our eyebrows act as a sponge for any sweat that might drop down our forehead into our eyes.
- If the human eye was a digital camera, it would have 576 megapixels!
- Red-green colour blindness is primarily found in men. The genes for the red and green colour receptors are found on the X chromosome, of which men only have one. Women, on the other hand, have two X chromosomes which means that even if one is faulty, a woman will still retain correct vision.
- In space, an astronaut cannot technically cry. Due to the lack of gravity in space, tears do not fall. Instead they collect in little balls and make a person’s eyes sting.
- People with blue-eyes share the same ancestor. Originally, all human beings had brown eyes, until a genetic mutation occurred between 6,000 and 10,000 years ago when the first blue-eyed person was born. Every single blue-eyed person shares this very distant relative. 3
- Some people are born with two differently coloured eyes. This condition is heterochromia.
- Blind people can see their dreams as long as they weren’t born blind.
- It’s impossible to sneeze with your eyes open. Your eyes and nose are connected by cranial nerves, so the stimulation from a sneeze travels up one nerve to the brain, then down another nerve to the eyelids, typically prompting a blink.
- We have all have unseen, harmless microscopic creatures living in our eyelashes. Gross! 4
- Eyes heal very quickly. With proper care, it only takes about 48 hours for the eye to repair!.
- Newborns don’t produce tears. They make crying sounds, but the tears don’t start flowing until they are about 4-13 weeks old.
- Cuttlefish have w-shaped pupils and goats have rectangular pupils. 1
- 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. What great teamwork!
- Even if no one in the past few generations of your family had blue or green eyes, these recessive traits can still appear in later generations.
- Your eyes start to develop just two weeks after conception.
- People generally read 25% slower on screen than on paper and when you read or stare at a computer you blink less often resulting in tired eyes. 2
- The muscles in the eye are 100 times stronger than they need to be to perform their function and they are actually the most active muscles in our whole body!
- The largest eye on the planet belongs to the Colossal Squid, and measures around 27cm across.
- Eyes began to develop 550 million years ago.1
This article is not a substitute for a consultation with your surgeon. Before choosing to proceed with laser eye surgery your surgeon will have a detailed discussion with you about the right procedure and about the potential complications.
A unique mix of expertise, experience and international reputation, Dr Ron Binetter is the figure behind the Binetter Eye Centre. With more than two decades of hands-on experience in eye surgery, Dr Binetter is a specialist in cataract, lens implantation and laser eye surgery. Learn more about Dr Ron Binetter’s background and qualifications.