EYE FACTS

• Eyes are thought to have first developed in animals, in a very basic form, around 550 million years ago.
• The world’s most common eye colour is brown.
• Your eye is the fastest muscle in your body – hence why when something happens quickly, we say ‘in the blink of an eye!
• You see with your brain, not your eyes. Our eyes function like a camera, capturing light and sending data back to the brain.
• Dogs can’t distinguish between red and green.
• We have two eyeballs in order to give us depth perception – comparing two images allows us to determine how far away an object is from us.
• Eye colour is determined by the amount of melanin in your iris
• 20/20 vision simply means that you have normal vision.
• Your eyes become tired when you read or stare at a computer, this is because you blink less often.
• Although our nose and ears keep growing throughout our lives, our eyes remain the same size from birth.
• You blink more when you talk.
• Diabetes is the number one cause of blindness in adults in the UK.
• People generally read 25 times slower on screen than on paper.
• All babies are colour blind at birth.
• The first blue-eyed person is said to have lived 6,000-10,000 years ago.
• It’s impossible to sneeze with your eyes open.
• An ostrich’s eye is bigger than its brain.
• The human eye can see 500 shades of grey.
• You blink on average 4,200,000 times a year.
• The cornea is the only tissue in the human body which doesn’t contain blood vessels.
• The human eye can function at 100% at any given moment, without needing to rest.
• Smoking reduces your night vision.
• Eyelashes have an average lifespan of five months.
• A newborn baby will cry, but not produce any tears. Babies do not produce tears until they are around six weeks old.
• Our eyes are made up of over 200 million working parts.
• In the right conditions and lighting, humans can see the light of a candle from 14 miles away.
• The shark cornea is used in human eye surgery as it is the most similar to the human cornea.
• 80% of vision impairment worldwide is curable.
• The human eye only sees three colours, red, blue and green. All other colours are combination of these.
• A camel’s eyelashes can measure up to 10cm long, to protect its eyelashes from blowing sand and debris in the desert.
• One of the most common cosmetic injuries is poking the eyeball with a mascara wand.
• The eye muscles are the most active muscles in the human body.
• The eyes of a chameleon are independent from each other, allowing it to look in two different directions at once.
• It’s possible to blink five times in a single second.
• Your eyes contain around 107 million light sensitive cells.
• Your eyes contain 7 million cones which help you see colour and detail, as well as 100 million cells called rods which help you to see better in the dark.
• Geckos can see colours around 350 times better than a human, even in dim lighting.
• A blink typically lasts 100-150 milliseconds.
• Blue-eyed people share a common ancestor with every other blue-eyed person in the world.
• Our eyes close automatically to protect us from perceived dangers.
• Your eyelashes keep dirt out of your eyes.
• The largest eye on the planet belongs to the Colossal Squid, and measures around 27cm across.
• Your eyebrows prevent sweat dripping into your eyes.
• Heterochromia refers to a condition where your eyes are two different colours.
• Our eyes are positioned in a hollowed eye socket, to protect the eye.
• Dolphins sleep with one eye open.
• The study of the iris is called iridology.
• Eyes are the second most complex organ after the brain.
• The Mayans believe that cross-eyes are attractive and would make efforts to ensure their children became cross-eyed.
• A dragonfly has 30,000 lenses in its eyes, assisting them with motion detection and making them very difficult for predators to kill.
• We have all have unseen, and harmless, microscopic creatures living in our eyelashes.
• The muscles in the eye are 100 times stronger than they need to be to perform their function.
• When your eyes are watering it may be a sign of dry-eye, and your eyes are producing more moisture to compensate.
• Your eyes start to develop just two weeks after conception.
• Owls cannot move their eyeballs – which has led to the distinctive way they turn their heads almost all the way around.
• The older we get, the less tears we produce.
• Eyes are able to process 36,000 pieces of information in a single hour.
• Colour blindness is more common in males.
• Reading in dim lighting does not damage your eyes but it may tire them out.
• Sitting too close to a TV won’t give you square eyes.
• The four-eyed fish can see both above and below water at the same time.
• Oily fish, vitamin A and vitamin C all help to preserve good eyesight.
• When working at a computer, you should follow the 20-20-20 rule – look at something twenty feet away from your computer every twenty minutes for twenty seconds.
• Snakes have no eyelids, just a thin membrane covering the eye.
• Eye transplants are currently impossible due to the sensitivity of the optic nerve.
• Only one sixth of the human eyeball is exposed.
• Pirates believed that wearing gold earrings improved their eyesight.
• Snakes have two sets of eyes – one set used to see, and the other to detect heat and movement.
• If you lined up all the eyelashes shed during one human life, they would measure 98 feet long.
• A scallop has around 100 eyes around the edge of its shell to detect predators.
• You see things upside down - it is your brain which turns the image the right way up.
• The space between your eyebrows is called the Glabella.
• Contrary to urban myth, contact lenses cannot become ‘lost’ behind your eye due to the structure of your eyeball.
• Goats have rectangular pupils to give them a wide field of vision.
• Everyone has one eye that is slightly stronger than the other.
• The eyeball weighs around 28 grams.
• Although the function of tears is to keep eyes clean, scientists don’t understand why we cry when we are upset.
• Owls are the only bird which can see the colour blue.
• Your nose gets runny when you cry as the tears drain into your nasal passages.
• About half of the human brain is dedicated to vision and seeing.
• Most hamsters only blink one eye at a time.
• The phrase ‘it’s all fun and games until someone loses an eye’ comes from Ancient Rome, as the only rule for their bloody wrestling matches was ‘no eye gouging.
• 80% of our memories are determined by what we see.
• Our eyes have small blind spots where the optic nerve passes through the retina, and our brains use the information from the other eye to fill this gap.
• Camels have three eyelids! This is to protect their eyes from sand blowing in the desert.
• You should always wear sunglasses and a hat in bright light to protect your eyes from UV rays.
• While a fingerprint has 40 unique characteristics, an iris has 256. This is why retina scans are increasingly being used for security purposes.
• Red-eye in photos is caused by light from the flash bouncing off the capillaries in people’s eyes.
• In an average life, your eyes will see 24 million different images.
• It is reported that men can read fine print better than women can.
• Scorpions can have as many as 12 eyes.
• ...and the box jellyfish has 24!
• Just behind our pupil is the lens - which is round, flat and thicker toward the middle.
• Albinism affects melanin production, perhaps resulting in extra sensitivity to light and a red-eyed appearance.
• The cornea is the transparent covering of the iris and pupil.
• Guinea pigs are born with their eyes open!
• Astigmatism refers to a curvature of the cornea or lens and toric lenses are prescribed to aid the individual’s vision.
• A worm has no eyes at all.
• An owl can see a moving mouse more than 150 feet away.
• Research has found that a tie tied too tightly can increase the risk of glaucoma in men.
• The perfect length of eye contact when you first meet someone is to acknowledge what colour eyes they have – about 4 seconds.