CHANCES You only really focus on your eyes when something is wrong – think a nasty infection or an eye test.
But your watchers can tell you a lot about your overall health, sometimes hinting at conditions like diabetes and high cholesterol.
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Your eye color may not be what you think it is, according to Dr. Philippa Kaye
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From how many times you blink a year to why we cry, Dr. Kaye explores bizarre facts about the eyes
Our series focusing on weird and wonderful facts about various body parts has seen bizarre revelations about your breasts, butt, mouth, vagina and penis.
Next up are the eyes – they might not seem that fascinating at first glance, but there’s a lot about this organ that might surprise you.
From whether you stop ‘seeing’ when you close your eyes while you sleep, to how many times you blink a year and how all eyes are actually brown – here are 10 fantastic facts about your eyes.
1. Your eyes don’t stop ‘seeing’ when you close them
Have you ever wondered what the hazy red glow you see when you close your eyes is?
Read more from Dr. Philippe
It’s the inside of your eyelids! Your eyes don’t stop seeing when you close your eyes, and your eyelids still let some light through.
Try closing your eyes in a lighted room, then hold your hand in front of your closed eyes, you will be able to see that it has become a little darker.
Even in the dark, you still see some kind of flashing light or moving stars when you close your eyes.
Your eyes even continue to ‘see’ and send visual information to your brain while you sleep. That is why it is more likely that you will wake up early, as it falls earlier in the summer.
Vision is not just the light you see.
Your observers also respond to stimuli. For example, even with your eyes closed, lights and colors can appear when you sneeze or cough, or even if you gently touch your eyelids while your eyes are closed.
2. The most common eye color is brown
It’s not quite as simple as you may have been taught, there are many more eye colors than brown, blue and green.
In fact, each iris, the colored part of your eye, is unique, although there are six main shades – brown, blue, green, grey, amber and hazel.
In albinism, a medical condition in which there is less melanin, which gives the skin, eyes and hair their color, the eyes can be different colors, most often blue, but including pink. Your iris is unique to you and is a way of identification, like your fingerprints.
3. But actually, all eyes are brown
This sounds contradictory, but they are, even though we see different colors when we look people in the eye.
This is because they have a different amount of melanin in their eye.
Melanin is brown, and the more melanin you have in your iris, the more light is absorbed, which means they look brown.
But if you have less melanin in the iris, that means more light can be reflected back, reflecting at shorter wavelengths that appear blue.
Add to that, some eyes seem to change color, depending on the light, because of what is reflected back.
This is also the reason why babies seem to be born with blue eyes, because they are still developing melanin in the iris.
4. You blink about 5 million times a year
Each blink lasts about one tenth of a second.
Even so, you can’t actually blink 10 blinks per second, the maximum is about five blinks per second, even if you really flutter those peepers!
Most people tend to blink every three or four seconds, or about 15 to twenty times a minute, about 5 million times a year.
If you find yourself in a staring contest and your eyes start to sting, the discomfort is caused by the tear film drying on your eyes.
So throw your head back and lift your chin so that you ‘stare’ at your competitor through the smallest opening in your eyelids.
Also, if you’re in a staring contest with a child, they might beat you, as a toddler’s tear film is more stable than an adult’s, especially if you have dry eyes, which means you’ll probably have to blink first!
5. And the eyes get tired
And not only from all that blinking!
There are many muscles in the eyes, but the feeling of heavy, tired eyes does not have to be from the eye muscles themselves.
It can be associated with headache, fever or even dry eyes.
Constantly looking at a computer screen can dry out the eyes, and even constantly focusing on small text while reading can lead to eye fatigue.
Try to stick to the 20-20-20 rule: if you spend a lot of time at the computer, look up every 20 minutes and focus 20 meters away for 20 seconds.
6. You need more than your eyes to see
Your eyes send visual information down the optic nerve to your brain, and they send a lot of it from the light you see.
But it’s the visual cortex in your brain that processes that information into an image.
The way the eye works means that all light is upside down, so if your eye ‘sees’ upside down, it’s your brain that translates the image the correct way.
7. Why do you cry?
Every time you blink, replenish the tear film over your eyes to prevent them from drying out.
You cry to keep your eyes clear, and in fact if you have dry eyes, your eyes may water to try to compensate.
But it is not known why we produce tears when we are upset, or because of other emotions such as fear, anger or happiness.
It may have evolved as a social cue, to help others understand what we are feeling, but not everyone cries in accordance with their emotions.
As for babies, they cry for various reasons, because they are hungry, or wet, or cold, or tired, or want to be cuddled, they cry to tell their caregivers something.
But that crying, at least at first, is a sound and doesn’t involve tears – those usually appear after about a month.
7. You don’t have a blind spot just while driving
The retina at the back of the eye contains an average of 120 million light-sensitive rods and 6 million cones involved in color vision.
The optic nerve connects your brain to the back of your eye, and where it connects to the retina is actually your blind spot, which means there’s essentially a hole in your vision, an area you can’t see.
But we have binocular vision, one eye filling in the gaps of the other.
This is not the same as a driving blind spot, it is the part of the road that cannot be seen by looking in the rearview or side mirrors, so always check over your shoulder!
8. When do you start seeing color?
Scientists have long thought that newborns are color blind and only see shades of black, white and gray, but recent research suggests that they can see some colors to a limited extent.
Their vision is not fully developed, in fact newborns can only focus on objects about 30 cm away from their face.
Red is thought to be the first color that babies can clearly distinguish and they see red, yellow and blue by about two months of age.
Color vision is thought to continue to develop until about four or five months of age.
9. How much eye contact is enough?
Not enough eye contact can be socially awkward, as can too much!
There have even been studies done on the perfect amount of eye contact when meeting someone for the first time, to strike the balance between connecting and making someone feel awkward.
Apparently the magic number is about four seconds!
In addition, your pupils dilate, not only in response to being in a dark room compared to a light one, but also if you are attracted to someone.
In fact, as far back as Roman times, the belladonna plant – belladonna meaning beautiful woman – was used by women to dilate their pupils.
But please don’t do it!
10. Your eyes are the window to…
The saying goes that your eyes are the window to your soul, but it may actually be that your eyes are the window to the rest of your health.
There may be changes in the back of the eye associated with medical conditions such as diabetes and high blood pressure. Be sure to test your eyes regularly.
10 steps for healthy eyes
THERE are lots of things you can do to keep your peepers healthy, from good nutrition to regular checkups.
- A healthy balanced diet can reduce your risk of developing common eye diseases – load up on spinach, red peppers, kale, leeks, avocados, peaches and blueberries, as well as fish like sardines, mackerel and tuna
- Exercise regularly to increase the crucial supply of oxygen to the optic nerve and reduce pressure in the eye
- Get a good night’s sleep to keep your eyes bright and refreshed
- Don’t smoke – tobacco chemicals can increase your risk of developing age-related macular degeneration (AMD) and cataracts
- Use safety glasses to protect your eyes from injury
- Limit the amount of alcohol you drink to protect yourself from eye diseases
- Wear sunglasses to protect against harmful UV rays that can increase your risk of developing cataracts and other age-related conditions over time
- Maintain a healthy weight to protect the retina from cell deterioration and age-related macular degeneration
- Drink plenty of water as dehydration can lead to dry, sore and irritated eyes
- Get an eye exam every two years
Source: Moorfields Eye Hospital
Categories: Optical Illusion
Source: HIS Education