Anatomy and model of the human eye
Our eyes are the organs that are responsible for vision and which serve as our window to the outside world. This article discuses the anatomy of the human eye and a model of the human eye, examining the different structures of the eye and their functions.
The eyeball is a round organ that is quite soft because of the presence of fatty tissue, sitting inside two sockets in the bony skull, which helps protect the eyes from injury. In the image below, you can see the anatomy of the human eye and its different structures.
The sclera is the outermost layer of the eyeball. It is the opaque, white part of the eye, what is commonly referred to as “the whites the eyes”. At the front of the eye, the sclera continues to merge with the cornea, which is the transparent dome-shaped covering over the iris and pupil. The space between the cornea and the lens (behind the pupil and responsible for refracting light) is called the anterior chamber and is filled with a transparent fluid called aqueous humor. The choroid is the middle layer of the eye, found between the sclera and the retina. It continues to form the ciliary body and then iris at the front of the eyeball. The iris is a flat, thin, ring-shaped structure attached to the anterior chamber. It contains a circular muscle (a type of sphincter muscle) which surrounds the pupil as well as radial muscles radiating towards the pupil.
Ciliary muscles are located in the ciliary body; these are the muscles responsible for constantly changing the shape of the lens for near and far vision. The zonules, also known as the suspensory ligaments, are rings of tiny fibers which hold the lens “suspended” in place.
The pupil is a hole in the center of the iris, situated in front of the lens, through which light passes to the retina. The retina is the part of the eye that is sensitive to light, and is the innermost layer lining the back of the eye. There are two types of light-detecting photoreceptors in the retina: cone cells, which allow us to see colors, and rod cells, which allow us to see in low light conditions. One area of the retina called the fovea, a small depression near the optic disc, has a very high concentration of cone photoreceptors.
The main muscles of the human eye are the lateral, medial, superior and inferior rectus muscles. The eye is innervated by the optic nerve, through which the central artery and vein run, supplying the eye with blood.