Structure of the Eye

Topic Content:

The section of the eye shows that the eye is a fluid-filled hollow structure. The wall of the eyeball consists of three layers; the outer sclera or sclerotic layer, the middle choroid and the inner retina. 

Below is the Vertical section of the Human Eye:

The Retina:

This is the innermost layer of the eye.

It is a delicate sheet of tissue which lays the inside of the eyeball. It contains light-sensitive cells; it gets its nourishment from the capillaries in the choroid.

The retina contains two types of photoreceptors.

Rods: The rods are extremely sensitive to light. Each human eye contains about 125 million rods. They are responsible for black-and-white vision. They continue to function in dim light.

Cones: The cones are sensitive to colour vision and light intensities. They do not respond to dim light, which is why at night we can no longer distinguish colour but see objects as shades of grey. Each human eye contains about 7 million cones. 

Fovea Centralis or Yellow Spot: 

This is the most sensitive spot on the retina. The yellow spot is densely packed with cones and hence it sends the