Human eye consists of three layers. The outer layer is a fibrous layer. It consists of posterior part Sclera which anteriorly forms Cornea. The middle layer is the vascular layer also known as uvea. It consists of a posterior part called a choroid that anteriorly forms a ciliary apparatus that further extends as iris. The iris is not continuous on both the sides and shows presence of a small opening known as pupil. The iris is responsible for the eye colour depending on the amount of melanin it contains. Thus it can be black or blue or green in humans. The innermost layer of the eye is the Retina.