We’re all apt to take our bodies for granted, but we might treat them with more respect if we appreciated what subtle, complex pieces of engineering they are. As you might expect, we’ve always been fascinated by the eye, which is our second most complex organ after the brain. Scientists are trying to make a bionic eye but the vision which users experience is still a long way behind nature’s incredible design.
So, how exactly do we see? Firstly, it’s important to remember that what we really see isn’t an object, but the light reflected off it. As light enters our eye, it is refracted by the cornea and the lens, focusing the image on the retina at the back of the eye.
In addition to this, our irises, the coloured parts of our eyes, work to increase or decrease the size of the pupil, thus allowing the right amount of light through to the retina. Too much light can damage the retina, while too little will prevent us from seeing.
The last part of the process is when the image on the retina is passed along the optic nerve to the brain, which then uses the information, whether it’s sending signals to the body not to walk into that tree (!), identifying a problem or working with the other senses to understand the situation more fully. It’s worth noting that the optic nerve contains 1.2 million nerve fibres!
As our eyes are forward facing, this gives us a relatively narrow field of vision, but more than makes up for it by creating stereoscopic vision. Each eye captures a slightly different image which our brains superimpose, allowing us to perceive depth and distance.
Our eyes are important and precious, but also very complicated and can go wrong. Not varying the way we use our eyes (sitting in front of the TV or computer too much, for example!), or not going outside enough and exposing our eyes to sunlight, can lead to eye problems.
For other people, long or short-sightedness is just a fact of life, passed on genetically. Short sightedness is a result of having eyeballs slightly too large, and causes the image to focus in front of the retina, rather than directly on it, sending a blurred image to the brain when looking at distant objects. People with long sight focus images behind the retina, seeing a blurred image of a close object. Long sightedness is caused by having a shorter eyeball, a flatter cornea or a problem with the lens inside the eye.
Nearly all types of eye problem can be corrected with laser eye surgery. A laser is used to reshape the cornea with micrometer accuracy, allowing your eyes to focus images directly on the retina and giving you perfect vision.
It’s important that we care for our eyes and correct our vision if necessary. Nature has given us these phenomenal pieces of engineering so we can use our most important sense for our everyday lives. As laser eye surgeons, we treat eyes and improve vision, but no scientist can truly recreate these complex organs. So it’s up to us all to do the best for our eyesight.