Did you know that 80% of what we learn is through our eyes?

The Human eye is full of amazing wonders that many of us never think about. Without them, we would never be able to conceive of Van Gogh’s body of work or even our own mothers’ faces.

The little orbs inside our skulls are powerful tools that give rise to many of human civilization’s greatest achievements.

Our eyes allow us to see the things around us. Many of us take this for granted, often only thinking about them when we need a new pair of prescription lenses. To gain a deeper appreciation for your eyes, check out these weird facts about eyes.

1. In the Beginning, We All Had Brown Eyes

That’s right, our blue-eyes friends are freaks. When humans first evolved, everyone had brown eyes. It wasn’t until a genetic mutation that took place about 6-10,000 years ago that the first blue-eyed person was born.

This mutation produced a “switch” that affected the ability to produce melanin. Melanin is the protein that is responsible for deeper colors in our eyes, hair, and skin. The lack of melanin produced paler-eyed individuals.

2. The Retina Receives an Inverse Image

Because of the curvature of our eyes, the image produced on the retina is upside down. Once the light reaches the retina, the optic nerve carries an electrical signal to the brain.

The brain has the sense to flip the image, allowing us to perceive the world in its upright form.

3. The Eyes Contain Some of the Most Active Muscles in the Human Body

The muscles in each eye are constantly working to maintain a focused image.

The pupils are always dilating to let more or less light into the eyes. The lens changes shape to focus light onto the retina at the back of the eye. However, sometimes people will need glasses or contacts, like these lenses, to help focus the images their eyes receive.

Additionally, the eyeball is in constant motion. The extraocular muscles attached to the sclera move the eye up, down, and side to side and rotate it.

All of these muscles are at work 24/7, even while you are asleep. During REM sleep, the eyes move rapidly and spontaneously.

4. Your Eyeballs Are Not the Same Size as an Adult and a Child

Many people claim that the eyeballs are full grown at birth. The internet is full of myths, and this is one. During the course of your lifetime, your eyeballs will grow significantly and reach full size around puberty.

At birth, the eyeballs are about 16.5 mm in length. By adulthood, they will reach about 24 mm.

5. Humans and Dogs Alike Seek Visual Cues From Another’s Eyes

It’s no secret that eye contact is important. We look into each other’s eyes as a means of showing respect as well as to better understand what another is feeling.

They say that the eyes are the windows to the soul. We can determine a lot about a person just by looking into his or her eyes. Think about walking into a bar and making eye contact with a stranger across the room.

His gaze may make you uncomfortable, because you get a sense that his intentions are not good. You may stay away from him for the rest of the night.

Dogs exhibit this behavior as well. Dogs are one of the few animal species that can understand human emotions. They look into our eyes to better understand how we are feeling.

When you are feeling down, your dog may look at you inquisitively. However, you should be careful about making direct eye contact with an unfamiliar dog. This can be perceived as a threat.

Other animals utilize the importance of eye contact, but dogs and humans share a special connection.

6. Eyes Heal Quickly

We’ve all gotten dirt or dust in our eyes at some point. It can sting and even leave us in a puddle of tears.

However, our eyes heal much quicker than most other parts of our bodies. With proper care, such as eye drops and reduced blinking, a corneal scratch can heal in just a couple of days.

7. Tears Have Different Compositions Depending on Their Origin

You’ve probably never wondered whether a tear of joy is different from a tear of grief or if either of those is different from an onion tear.

Tears are divided into three categories. Psychic tears are produced as a response to an extreme emotion, whether it be positive or negative. Basal tears are constantly produced to keep the cornea lubricated. Reflex tears are produced in response to an irritant.

Tears from each category contain a unique combination of molecules suspended in salt water. Psychic tears contain hormones like leucine enkephalin, a painkiller that is released in response to stress.

8. Doctors Are Yet to Be Able to Transplant an Eyeball

Scientists and doctors have figured out how to transplant hearts, lungs, kidneys, and even feces. However, the eyes are the second most complex organ in the human body after the brain.

Each optic nerve contains between 770,000 and 1.7 million nerve fibers, making it incredibly sensitive and difficult to reconstruct. However, with new and upcoming science regarding nerve regeneration, this may one day be a possibility.

One team of scientists in the US wants to see this dream become a reality in the next decade.

9. People Who are Born Blind Do Not Experience Visual Hallucinations

You’ve probably wondered what it is like for a blind person to take a psychedelic drug. For someone who is born blind, the concept of visual experience is completely foreign.

For those of us who have experimented with such experiences, the visual component seems so integral. However, a congenitally blind person will likely not have a visual experience at all.

A study on a man who was born blind suggests that the psychedelic experience is wholly auditory and tactile to someone who has never seen the light of day. The man reported feeling music in ways that many of us could probably never even imagine.

10. People Who Become Blind Later in Life Still See Their Dreams

Because they have had visual experiences, someone who is not born blind may still dream visually.

However, the longer someone lives without sight, the less likely they are to dream visually. Their dreams will likely include other sensations, such as taste, sound, or touch.

Most of us are used to visually rich dreams, but not everyone experiences the world in the same way. Thus, not everyone dreams in the same way.

Learn Beyond Facts About Eyes

Human beings are weird creatures, and we are fascinated by weird things. This list is just the tip of the iceberg. If you enjoyed this compilation of facts about eyes, then there are plenty of other weird things to find out.