Explanation

Our paired eyes are located in sockets of skull called orbits. The adult human eyeball is nearly spherical in structure. The wall of the eyeball is composed of three layers. The anterior portion of this layer is called cornea. The middle layer choroid contains many blood vessels and looks bluish in colour The inner layer is retina and it contains three layers of cells, i.e., from inside to outside called ganglion cells, bipolar cells and photoreceptor cells