THE EYES — Part 1 of 3
The eyes are the window to the soul as they say. But they are also a very intricate piece of biological machinery that we use every day without even thinking about it. We’ve broken down the eyes, their many parts and how they function into a three-part blog series so you can have a better understanding of what’s going on inside your eyes and head.
Eyes are constantly taking in information whether you realize it or not. From the colours around you, to the objects in the far distance to when you read and write and beyond. The information collected is then sent to your brain and that is how you know what you are seeing.
The Basics
Your eye balls are nestled inside your eye sockets inside your skull. And from the outside, the eye balls are protected by your eyelids. Whenever you blink (which is several times a minute), you are protecting your eyes by keeping the moisture in. Whether you’ve noticed or not, your eyelids also protect your eyes in other ways. When you encounter bright light (like in the sun for instance), your eyes automatically close in which allows your eye time to adjust to the sudden brightness. Similarly, if something gets too close to your eyes, the lids will blink in order to make sure nothing gets in. Meanwhile your eyelashes have their own job which is to keep dirt and other particles out of your eyes.
What You See
On the outside, you can see the white part of your eye, as well as the coloured (green, blue, brown, grey) and the black parts of the eye. The white part is called the sclera and covers most of the eyeball and keeps everything together, including the tiny blood vessels you see if you look really closely.
What You Don’t See
There is a transparent layer overtop of your eye that is called the cornea, specifically over the coloured part of the eye (the iris). The cornea is what helps your eye focus when light comes into the eyes and is made of a clear tissue. The anterior chamber sits between the cornea and the iris, and is a clear space filled with a transparent fluid that feeds the eye with all the nutrients it needs to stay healthy.
The Iris and the Pupil
The cornea covers the iris, the pupil and the anterior chamber of your eyes. The iris is the colourful part of your eyes. The iris has small muscles that are attached that manage how much light the iris lets in through the pupil, which is the black circle in the centre of the eye. You might have noticed your pupil can get smaller or bigger depending on how bright (or dim) it is; this is how it helps the eye sees under darker conditions. By getting bigger, the pupil lets in more light which makes it a little bit easier to see. And when there is too much light, the pupil gets smaller so as not to overwhelm the eye with the brightness.
Next week we’ll talk about what’s going on behind the scenes. The lens, the retina and how they process the light as well as the eye muscles, the brain and how they translate the information into sight.