Question

If the circular ciliary muscles of the eye are unable to contract, the

• A. Lens will become more convex
• B. Lens will be thin and stretched
• C. Vision will be lost completely
• D. Bright light will have no adverse effect on retina

Answer 1

The correct option is B Lens will be thin and stretched

Ciliary body and the attached suspensory ligament change the shape (flattened or round) of the lens through relaxation and contraction of ciliary muscles and thereby the focal length to focus on the distant and near object. Contraction of ciliary muscles releases the suspensory ligaments and allow the lens to become round (convex) while relaxation of these muscles makes the lens taut. Since ciliary muscles are involved in accommodation required for close vision, loss of their contraction would not cause loss of vision but would affect the close vision only. The amount of light entering retina is controlled by the iris.

So, the correct answer is option B.