5 Fascinating Facts About Your Eyes

Medically Reviewed By William C. Lloyd III, MD, FACS
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  • Henry David Thoreau was right when he said the eye is the jewel of the body. Your pair of peepers is definitely precious. Did you know human eyes are one of a kind and their complexity makes it impossible to transplant an entire eye? That’s because each eyeball is controlled by more than 1 million nerves and uses 50% of your brain power to see. If that turned your head, take a peek at a few more fascinating facts about your eyes.

  • 1
    Brown is the most prominent eye color.

    When human eyes first developed, we all had brown ones. As the population evolved individuals expressed different amounts of brown melanin pigment in the colored iris. Some sources say brown eyes actually have blue beneath the brown pigment and you can have a laser procedure to turn your blue eyes brown. But why change them? Your eyes hold a large part of your personal history. Your retina has 256 unique characteristics that can help identify you, much like a fingerprint. Plus, 80% of learning and memories is created through our eyes. Your eyes play a huge role in who you are, whatever their color.

  • 2
    Eyes heal faster than you think.
    Doctor examining patients eyes

    The thought of getting poked in the eye makes most people cringe, but it turns out eye injuries heal quickly. A simple eye abrasion, like a corneal scratch, can heal in 24 to 48 hours. That is, if you take good care of it. Eye pain from a scratch is a sign you need medical care to keep the wound from getting infected. This is critical because an eye infection can lead to blindness. If you scratch your eye, visit your doctor immediately to see if you need antibiotics to prevent infection.

  • 3
    Size matters.
    Eye close-up

    We’re all born with 16mm eyes and as we grow, they grow. By age 3, our eyes are roughly 23mm and reach their maximum size of 24mm at around puberty. Growth spurts can often cause nearsighted or farsighted vision, if the length of the eye changes. If your eye is longer than normal, you’ll be nearsighted. If it’s shorter, you’re farsighted. Any change in eye length, even a millimeter, can alter your prescription for corrective lenses. So the long and short of it is this: If you need vision correction, get a yearly eye exam to make sure your eye length hasn’t changed.

  • 4
    Your eyes can get sunburned.

    Here’s an unexpected fact about eyes: They can get sunburned. Sunglasses aren’t just for preventing glare (and looking cool). They actually play an important part in protecting your eyes from damaging UVA and UVB rays. Chronic sun exposure can cause changes to the surface of your eye similar to sun damage elsewhere. The effects aren’t as immediate and happen slowly with prolonged exposure to the sun. This results in thickened tissue on the eye and you may need surgery to remove it. A pair of good quality sunglasses that block at least 98% of UVA and UVB rays will keep your eyes healthy. As a bonus, they’ll also protect your eyes from debris and dust!

  • 5
    Newborns never shed a tear.
    Newborn baby

    Mothers of newborns can put that “no more tears” shampoo back on the shelf, because newborn babies don’t actually cry tears. They can certainly make crying sounds, but their eyes don’t make tears until they’re between 4 to 13 weeks old. Though their eyes start forming 2 weeks after conception, it takes 4 months for children to fully develop the ability to see colors and objects. But they do love looking at your face, especially your eyes. Maybe that’s because your pupils expand 45% when you look at someone you love.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 May 5
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.