Our eyes are one of the most significant tools we use to process the world around us. They allow us to interpret shapes, faces, colors, and depth by translating the light that reflects off of these things into electrical signals that the brain reads as images.
The eyes sit in cone-shaped cavities in our skull called sockets which are surrounded by 6 motion-regulating muscles and multiple layers of fatty tissue that help to protect the eye and give it flexibility. Eyebrows, eyelashes, and eyelids also contribute to this effort.
The eye itself is made of 10 general components that all work together to keep us seeing well every day.
Cornea The cornea is the outermost layer of the eye and is primarily responsible for focusing the light that comes into our eyes. There are 5 layers to the cornea. The outer layer acts as a kind of shield to the elements and can usually repair itself within a few days of suffering a minor injury. The deeper layers exist mainly to strengthen the eye.
Pupil The pupil is the black circle in the center of the eye, and its primary function is to monitor the amount of light that comes into the eye. When there is a lot of light, the pupil contracts to keep the light from overwhelming the eye. When there is very little light, the pupil expands so it can soak up as much as possible.
Iris The iris is the colored part of the eye. Although it might seem purely cosmetic, the iris actually functions to adjust the size of the pupil. It has muscles that contract or expand depending on the amount of light the pupil needs to process images.
Lens The lens exists behind the pupil and is responsible for allowing your eyes to focus on small details like words in a book. The lens is in a constant state of adjustment as it becomes thinner or thicker to accommodate the detailed input it receives. With age, the lens looses a lot of its elasticity which often results in cataracts and presbyopia, i.e. nearsightedness, because the lens cannot adjust as well to its surroundings as it used to.
Vitreous Humour The vitreous humour is a gel-like substance that helps to keep the eyeball in its proper, circular shape. This is the area in the eye where floaters develop as pieces of the vitreous humor clump together and cast shadows onto the retina. With age, the vitreous humor begins to shrink and can cause problems like posterior retinal detachment or retinal tears.
Retina The retina is the area at the back of the eye that receives the refined, visual message from the front of the eye, and it transmits that visual message to the brain using electrical signals.
Sclera The sclera is the white part of the eye, and its main function is to provide strength, structure, and protection for the eye. The sclera contains blood vessels that can tell an eye doctor a lot about the state of your overall health.