How does the eye-lens differ from the ordinary convex lens made of glass?

How does eye adjust itself to deal with light of varying intensity?

Explain why, we cannot see our surroundings clearly when we enter a darkened cinema hall from bright sunshine but our vision improves after some time.

Name the part of the eye:

(a) which controls the amount of light entering the eye.

(b) which converges light rays to form the image.

(c) on which image is formed.

(d) which carries the image to brain.

(e) which changes the curvature (or thickness) of eye-lens to focus objects lying at various distances.

Name the cells on the retina of an eye:

(a) which are sensitive to bright light.

(b) which are sensitive to dim light.

(c) which produce sensation of colour.