Sometimes we take our vision for granted. From the moment we wake up until we fall asleep, our vision is there as one of our major senses that helps us build and make sense of our world. Our daily lives depend on consuming information visually, from reading at a computer, to viewing objects and performing tasks with dexterity.
But have you ever thought about how complex your visual system is? Or what about the process behind your eyes and brain that piece together your reality?
At a very basic level, light reflects off of objects and then bounces into our eye where optic nerves process this information and send signals to the brain. But let’s take a deeper dive into this process first.
Light travels or is reflected from nearby objects where it passes through the pupil. Depending on the amount of light getting reflected into the eye, the iris will change in size to allow more or less light in. When you step outside during a bright day you may feel blinded at first before your eyes adjust. This is the simple process of your iris adapting to lighting conditions.
Once the light enters the eye it is then focused onto the retina, and depending on the distance of the object being viewed, the lenses will change shape. This is called accommodation and involves ligaments surrounding your eye that pull or release the lense to focus properly. Of course, if you are nearsighted or farsighted, this action doesn’t happen perfectly and the use of corrective lenses is needed.
After light is focused on the retina, it’s then transformed into electrical impulses. Here is where the fun stuff happens. The information in the impulses travels from the optic nerve to the brain, and is actually upside down when it gets there. The brain has to transform the image right side up for us to comprehend it.
Our eyes do a really good job of capturing light from objects around us and transforming that into information used by our brains, but our eyes don’t actually “see” anything. That part is done by our visual cortex.
Our eyes being slightly apart creates an image that needs to be corrected. This gives us the ability to see in stereo and interpret 3D images. Neurons work simultaneously to rebuild the image passed to the brain from the optic nerve. Your brain actually responds better to shapes and edges first, while colour and shading are used to further differentiate objects from one another.
As you can see, there is more going on with your visual system than just the light hitting it. Complex parts of the brain that have evolved over time to produce a crisp, sharp image are constantly being used to help you see the world around you. Now you know why those regular eye exams are so important.