The human eye is an organ that reacts to light and has several purposes. Rod and cone cells in the retina allow conscious light perception and vision including colour differentiation and the perception of depth. The eye is made up of three coats, enclosing three transparent structures. The outermost layer, known as the fibrous tunic, is composed of the cornea and sclera. The middle layer, known as the vascular tunic or uvea, consists of the choroid, ciliary body, and iris. The innermost is the retina, which gets its circulation from the vessels of the choroid as well as the retinal vessels, which can be seen in an ophthalmoscope. Within these coats are the aqueous humour, the vitreous body, and the flexible lens. |