How Your Eyes work with your Brain to See
How you see the world around you and how you interact with it is all thanks to the intricate pathways that link the back of your eyes to the back of your head.
Your brain is essentially a control panel that is responsible for every single bodily function, including the power of sight.
Areas of the brain
The brain can be separated into three main areas – cerebrum, cerebellum and brain stem.
The largest part of the brain is the cerebrum which is made up of four separate lobes: the frontal lobe, temporal lobe, parietal lobe and occipital lobe.
Your brain assembles images of what you see in the primary visual cortex at the back of the brain, more specifically, in the occipital lobe.
Light travels through the eye to the brain
In order to see, light that enters through the eyes is changed and translated into a range of impulses that can be understood by the brain.
Retina: The retina located at the back of the eye contains photoreceptor cells that convert rays of light into electrochemical signals that pass through the layers of the retina to ganglion cells. These cells then send information to the brain via the optic nerve.
Optic Nerve: A vital cranial nerve, the optic nerve is the pathway that carries nerve impulses from each eye to the brain. Information from the right eye travels to the left hemisphere and vice versa because the optic nerve intersects at the optic chiasm.
Optic Chiasm: Located deep inside the brain under the hypothalamus (controls body temperature and works in tandem with the pituitary gland), the optic chiasm is the crossroads at which the optic nerve from each eye detours to the opposite side of the brain.
Occipital Lobe: Found at the back of the brain, just above the cerebellum, the occipital lobe processes the impulses it receives from the optic nerve. It is the centre of your visual perception system and is responsible for how you see the world around you.
Visual Cortex: This is the area of the brain where both sensory and motor information is combined with sight. For example, it allows you to understand that you’re looking at a book, and then, enable you to pick it up.
Is the brain responsible for my refractive error?
The brain can only understand the information it receives, and if the message gets muddled on the way to the occipital lobe, it is through no fault of the brain itself.
Your refractive error is caused by the way in which your eye has grown or the shape of your cornea – your eyeball can be too short or too long, or your cornea can be too steep, too shallow or completely misshapen.
Laser Eye Surgery works by correcting the shape of your cornea so that light can reach the back of your eye correctly and send clear images to the brain.