World Sight Day this year is 10 October 2019, a day that helps to draw attention to global blindness and visual impairment. The goal is to raise public awareness of eye health, encourage people to get a sight test more regularly and ultimately, put a stop to avoidable blindness. Over 50% of sight loss can be avoided, which means there's a lot we can do to take better care of our eyes.
Second only to your brain, the eyes are the most complex organ in the human body. Due to their complexity, our eyes are being used more and more in place of fingerprint scanners for identification. Although fingerprints have 40 unique elements, the iris of our eyes has 256.
Here are some interesting facts about eyes:
1. What is the maximum resolution of the human eye?
Scientist and photographer Dr. Roger Clark says the human eye is 576 megapixels, a much higher resolution than any camera could give you. 576 megapixels is a lot when you compare it to your smart phone, which has a fraction of that power. Our eyes work more like a live stream video than they do a camera, giving you a constant show of seamless, high resolution footage.
2. We see things upside down
We actually see things upside down, it’s our brains that convert the image before us the right way up. When we're born we're colour blind and for the first week or two, we see the world upside down. This is because we haven’t yet developed the ability to flip the image in front of us.
Bojana Danilovic from Serbia was born with spatial orientation, a phenomenon that stops her brain from converting the image in front of her the right way up. Literally seeing the world upside down isn’t as annoying as you might think. The screen on her computer is permanently flipped and she has a separate television to her family which rests permanently upside down.
3. Can you sneeze with your eyes open?
We're busting two myths here. Not only can you sneeze with your eyes open, your eyes won't pop out if you do. Closing our eyes when we sneeze is a natural reflex, although nobody really knows why. It could be to stop whatever comes out of our noses from going into our eyes, or there could be no reason at all.
4. Your eyes can get sunburned
When your eyes are exposed to too much UV (Ultraviolet) light you can develop a condition called photokeratitis. This can happen from too much natural sunlight as well as artificial. It’s particularly likely in snowy conditions on mountain tops because snow is very reflective. This painful condition can be avoided by always wearing sunglasses or snow goggles in bright conditions.
5. Pupils dilate when we’re excited
Have you ever noticed how cats’ eyes get bigger when they look at prey, or right before they’re about to jump on your lap? Just like cats, our pupils expand when we’re excited, interested or scared. Equally, when we’re less engaged, our pupils also decrease in size.
6. Can you see mental illness in the eyes?
Researchers from the University of Aberdeen discovered that eye tests can detect Schizophrenia with 100% accuracy. In a group of Schizophrenia patients and a control group, the patients that had Schizophrenia performed worse overall. Scientists have been aware of people with Schizophrenia having abnormal eye patterns of for some time, but only now is this being used to help diagnose the mental illness.
7. What causes red eyes in photos?
When someone takes a picture of you using flash, some of that light is reflected back at the camera. Light bounces off the cornea and brightens the blood supply at the back of your eyes, producing the red eye-effect in photos. Of course, your eyes could be red for a different reason. If you find your eyes dry, red or uncomfortable, consider using some eye drops and if the problem still persists, visit your eye doctor.
8. Contact lenses can’t get stuck behind your eye
Good news, it’s physically impossible for your contact lenses to get stuck behind your eyes. The eye is very clever at stopping foreign objects from getting that far back. The thin membrane that covers the eye is called the conjunctiva, this forms a blockade to any unwanted objects. If your contact lens has moved and you can no longer see it, that only means the lens is stuck on the inner, upper eyelid.