All within something as small as a large marble, photons of light are transformed into streams of accurate, detailed, moving images that we are able to interpret and react to. Our sense of sight keeps us connected to our surroundings in so many ways, from showing us the faces of those we love to enabling us to read or drive or play sports. How can our eyes do so much?
We won’t be giving you a complete glossary of eye anatomy terms, but we want to go over the structures that are most important for creating the images we see. We’ll start at the front of the eye and work our way back.
Try focusing on an object and closing one eye, then switching to the other eye. The distance between our eyes is small, but it’s enough that you see things from a slightly different angle from your left eye and your right. The way the two images combine into one field of vision is called binocular vision. It creates a live 3D image that gives us depth perception, or the ability to judge relative distances of objects from us, a critical visual skill.
Once an image reaches the optic nerve, it travels to the occipital lobe in the back of the brain, where the visual cortex is located. Seeing takes a lot of brainpower, with 20% of the human brain dedicated to visual processing and another 40% involved in assisting with vision+meaning, vision+motor, vision+touch, or vision+attention. Numerous times per second, the brain absorbs and processes new visual data, which is how we perceive, understand, and react to motion.
All of those amazing structures wouldn’t be able to do their jobs without the support of others. The eyebrows, eyelids, and eyelashes all help protect our eyes from outside debris getting in. Blinking refreshes the tear film and clears away debris and other contaminants, and the tear film is replenished and maintained by a series of glands and ducts.
We will never stop being amazed by how all these structures and systems work together to create our sense of vision, but all this complexity means there are a lot of ways for something to go wrong. That’s where the eye doctor comes in! Make sure to keep up with your regular eye exams and contact us if anything changes about your eyesight.