How Does the Human Eye Work?

In our previous adventure, we learned about the superpowers of lizards' eyes, which help lizards see colours by moonlight. In fact, gecko colour vision is 350 times more sensitive to low light than ours.

However, did you know that our human eyes are equally extraordinary? Because our eyes are less sensitive than gecko colour vision, our pupils change size whenever the light changes! This means that they grow or shrink to allow just the right amount of light to enter your eyes and enable you to see.

But what does it mean for light to enter our eyes? Well, buckle up for a journey into the enchanting world of our very own eyes and their incredible feats!

The marvellous machinery of our eyes

Picture your eyes as tiny cameras in your head. They're only 2.5cm in diameter but are capable of capturing images from the tiniest ant to a distant twinkling star. These magical cameras have essential parts that work together to create the wondrous world you see every day.

Just like a superhero's shield, the cornea is the clear covering over your eye. When light bounces off an object, it enters through the cornea, then through the pupil—the black circle in the centre of your iris. Meanwhile, the lens is like the zoom button. This focuses the light onto the retina, which is a thin lining at the back of your eye as delicate as wet tissue.

Lastly, the retina acts like camera film, capturing the images of the world around you. The brain, the ultimate superhero, instantly processes these images, telling you to duck when a fly zooms your way!

Problems and solutions with our eyes

Just like any superhero, our eyes aren't invincible. Sometimes they need a little help. Imagine if the lens inside your eyes cannot focus the light perfectly, or if your corneas were a bit more squished – which happens in a condition called astigmatism – causing the light to not land properly on the retina. That's when the eye doctor, who is like a superhero eye expert, comes to the rescue.

The eye doctor can determine your spherical number, or how strong the eye correction needs to be, and your cylinder number, or how much astigmatism you have. These values will help in understanding a prescription, which is what is used to make the lenses of your glasses work properly. This will ensure that your eyeglasses function like a special map for your eyes, bending the light enough to land exactly where it should on your retina.

However, why do some eyes need more help than others? While some eye problems can come from our parents, most are actually caused by environmental factors. That’s why it’s important to take proper care of our eyes! For instance, staring at screens for too long can make our eyes longer, preventing them from bending light the way they should. This can make you nearsighted, so distant objects appear blurry. 

Visiting your eye doctor frequently can help prevent these problems. Don’t go only when you notice discomfort, because even painless changes like your eyes changing colour can mean deeper concerns, such as infections or too much sun exposure. Our eyes do what they can to protect themselves, like producing more melanin, or pigment, to prevent sun damage. However, a regular check-up every two years can make sure that your eyes aren’t overworking themselves, so they remain in their strongest condition throughout your lives.

Remember, taking care of your eyes is like being the superhero of your own story. Giving them breaks from screens, wearing sunglasses in the sun, and blinking often are simple acts of kindness towards these incredible, tiny cameras in your head.