Function of iris is to
(a) move lens forward and backward
(b) refract light rays
(c) bring about movements of eyelids
(d) alter the size of pupil
The correct option is (d) alter the size of pupil.
Explanation:
Iris controls the amount of light that reaches the photosensors at the back of the eye. It consists of circular sphincters and radial dilators. The function of iris is to alter the size of pupil.
