23 facts about your eyes
Our ‘windows to the soul’ are more complicated than you could ever imagine. Here we take a look at some of the unknowns of our most precious sense.
1. Newborn babies don’t shed tears when they cry as their tear ducts haven’t fully formed. Teardrops begin to appear between 1 and 3 months of age.
2. The average blink lasts for about 1/10th of a second.
3. Each eye contains 107 million cells and all of them are light sensitive.
4. 20/20 vision refers to being able to read an eye chart from 20 feet away.
5. Your eyes actually see images upside down and then send these to the brain where they are flipped and corrected for us.
6. The human eye will focus on around 50 things per second.
7. Only 1/6th of the eyeball is visible.
8. The human eye can distinguish about 2.7 million different colours and 500 shades of grey.
9. Some people are born with different coloured eyes – a condition called heterochromia.
10. Eyelashes have a lifespan of around 5 months.
11. Type 2 diabetes is often first detected during an eye exam.
12. Shark corneas are very similar to human corneas and have been used as replacements in human eye surgeries.
13. The term ‘in the blink of an eye’ came about because it’s the fastest muscle in the body.
14. Eye colour can change depending on the lighting conditions, especially lighter-coloured eyes.
15. Although reading in dim light makes you tired, it does not weaken your eyesight.
16. There is a word for fear of eyes – ommatophobia.
17. Eyes can get sunburnt so it’s important to wear sunglasses that protect against UVA and UVB rays.
18. Kim Goodman holds the furthest eyeball pop in the Guinness World Records with a protrusion of 12mm beyond her eye sockets.
19. Your eyeballs grow as you age, reaching their maximum size when you hit puberty.
20. Staring directly into the sun can make you go blind, as the sun burns a spot in the retina.
21. The external muscles that move the eyes are 100 times more powerful than they need to be.
22. There is no evidence to suggest sitting too close to the TV damages your eyesight.
23. Eyes are composed of more than 2 million working parts.