7 interesting facts about the human eyes

Here are 7 of the most curious facts about the human eyes.

How often do we take a moment to appreciate these incredible organs?

In my opinion, not often enough.

So let’s do it together right now!

Human eyes development

The development of human eyes starts only two weeks after the conception of a baby.

These organs have a very complicated structure, so the process takes time.

Many people claim that these are the only organs in the human body that don’t grow after birth.

The truth is, they do.

By the time the baby is 3 months old, the eyes are still developing and growing.

At that point, the corneas stop growing for good.

However, the front-to-back length of the eyeball could continue increasing.

And since our head grows too, the distance between the two eyeballs also does.

We don’t see with our eyes

There’s a reason why human eyes are the prototypes of cameras.

They only let the light in through the pupil, which leads to forming an upside-down image.

It has to be turned around.

The brain does that and allows us to see everything as it is.

Furthermore, the visual information we perceive is being processed by the brain.

Therefore, we only observe with the eyes, but literally, see with our brain.

That makes sense because the hierarchy must be kept – the brain is the most complex organ in the body.

The eyes are on the second place. Besides, our brain is constantly engaged by the eyes.

“More than 50 percent of the cortex, the surface of the brain, is devoted to processing visual information.”, says Williams, the William G. Allyn Professor of Medical Optics.

Functions of the eye muscles

The muscle of the eyelid reacts faster than any other one in the entire body.

Blinking is meant to protect the eye from an unexpected danger and the muscle is 100 times stronger than it needs to be to perform its function properly.

There are also muscles on the back of your eyeball.

They’re responsible for our ability to focus on close and distant objects.

When we spend too much time in front of the laptop for instance, they don’t contract often enough.

That leads to sight problems.

You can easily prevent them by following the 20-20-20 rule.

Every 20 minutes get up and for 20 seconds stare at an object which is 20 feet away.

This will train the muscles and “restart” your eyes and they’ll be prepared for the next 20 minutes in front of the monitor.

There’s another hack to train your eyes which is as old as time.

Lighten up a candle and move it back and forward in front of your face.

Try focusing on the flame each time.

And you’re done with the eye workout for today:)

The weird floating things you see

Have you ever wondered what are those weird colorless bug-looking things you see sometimes?

I did for ages.

Well, here’s the simplified answer:

The first option is that you’re seeing the “floaters”.

They could be pieces of tissue, red blood cells or protein cells.

What they do is casting shadows on the sensitive part of your eye – the retina.

They move along with the movements you make with your eyes and look like tiny bugs which change shapes.

The “floaters” are clearly noticeable when you’re staring at a bright surface like snow or blue sky.

The second option is that you’re experiencing the “blue field entoptic phenomenon” – dots of light appearing when you’re looking at the bright blue sky.

These are actually white blood cells, letting the light through your retina.

They move in your capillaries and that’s why you see them shifting in time with your pulse.

The uniqueness of the cornea

The cornea is unique because of its transparency and the lack of blood vessels.

This allows the light to pass through and get to the retina.

There’s a wide-spread myth that a shark cornea has been used for human cornea transplantation once.

The explanation is that both structures are very similar.

However, there’s no evidence for these statements.

On the other hand, researches on pig corneas show that they may be appropriate for this kind of surgery.

In a few years, people with damaged corneas may replace them with pig ones.

Progressive, right?


What causes red eyes in photos

When the camera light hits our eyes, the pupils widen as usual.

However, they’re unable to reach the speed of a flashlight and constrict as fast as it disappears.

The light reaches the retina, but it’s too much and can’t be all absorbed.

That’s why it simply illuminates the capillaries at the back of the eye and (surprise, surprise!) they are red.

We all know the anti-red-eye function on the photo editors.

But is there something we can do to prevent this annoying effect?

It turns out that you have to avoid looking directly at the camera lens.

Just try shifting your vision slightly and see if it works for you.

In case it doesn’t, move further from the camera.

This way the light that reaches your eyes will be less aggressive.

Why do we cry?

There are 3 types of tears:

The basal ones keep the cornea nourished.

Thanks to them your eyes don’t dry out, even when exposed to extreme conditions like too cold or too hot weather.

The reflex tears are caused by different irritations such as dust, onion vapors, fallen eyelashes…

We all know them very well.

The psychic tears are most interesting.

Years have passed by before scientists explain what causes them.

It’s a very complicated process, of course.

In general, certain strong emotional reactions like sadness, anger or happiness trigger our nervous system.

Then it tells the “tear-producing center” that it needs to do its job.

What’s more curious is that this last type of tears is known to contain a higher level of stress hormones than the other ones.

So you literally cry the emotions out.


In order to finish this article in a more cheerful way,

I appeal to you: Be proud of your eyes!

I shared with you only 7 of the countless ways they amaze us every day.

Our software Iris also can be your eye’s friend!

We all know that monitors emitting harmful blue light, but with Iris, you can prevent it and improve eyesight.

Take good care of them and don’t forget to be grateful – thanks to them you get to enjoy the wonderful world around you.

Author: Slaveya Nikova


  1. https://www.lenstore.co.uk/eyecare/101-amazing-eye-facts
  2. https://versanthealth.com/blog/15-facts-about-all-things-eyes/
  3. https://birthworks.org/do-human-eyes-remain-the-same-size-from-birth-to-death-by-cathy-daub-cce-cd-bwi/
  4. https://www.youtube.com/watch?v=Y6e_m9iq-4Q
  5. https://www.quora.com/Are-shark-corneas-really-used-for-human-cornea-transplantation
  6. https://www.goodeyes.com/blog/red-eyes-photos/
  7. https://www.independent.co.uk/life-style/health-and-families/features/why-do-we-cry-the-science-of-tears-9741287.html

Read more:

How can I take care of my eyes

Heterochromia – two different-colored eyes?

The eyes: from ancient jellyfish to modern humans

Blue light and Eyes


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