# The change in focal length of an eye lens is caused by the action of the

Question.
The change in focal length of an eye lens is caused by the action of the

(a) pupil

(b) retina

(c) ciliary muscles

(d) iris

solution:

Option (c) is correct.

By relaxation or contraction of ciliary muscles, the curvature of the eye lens changes which eventually changes the focal length of eye lens.