Describe the structure of human eye ?

Explanation

Retina is the inner coat of the eye. It consist of a pigmented epithelium and a neural portion. The pigmented epithelium is a sheet of melanin containing epithelial cells. The neural portion has three layers namely photoreceptor layer, bipolar cell layer and ganglion cell layer.
Photoreceptor layer consist of rods and cones. Rods contain a protein called rhodopsin. Rods are concerned with dim light. Cones contain a visual pigment called iodopsin and they are important in daylight vision and colour vision. There are three types of cones and are response to red. green and blue colours.
The centre of the posterior portion of the retina is called yellow spot. A depression present in the yellow spot is called .Forea. contractile and it contains only cones.Forea is responsible for sharp vision. The region of retina which is devoid of rods and cones is known as blind spot (or) optic disc, which form the optic nerve called 2nd cranial nerve.