Question

Function of ciliary Muscles is
a. To contract pupil when one move in sunlight
b. To keep value in position
c. To rotate eyeball
d. To change shape of lens

Answer 1

Hint: Ciliary muscle is a smooth muscle ring located in the eye's middle layer also known as vascular layer that is responsible for accommodation of viewing objects at varying distances along with it regulates the flow of aqueous humor into Schlemm's canal. The muscle changes the shape of the lens within the eye, but it does not affect the size of the pupil which is carried out by the sphincter pupillae muscle as well as dilator pupillae.

Complete answer:
- The iris muscle is a contractile structure, mainly consists of smooth muscle, and is surrounded by the pupil. The sunlight or light enters the eye through the pupil, and the iris controls as well as regulates the amount of light by controlling the size of the pupil. This is known as the pupillary light reflex.
- Talking about the human eye there is no such muscle which is responsible to keep value in position. The statement is proven wrong considering the question.
- Superior oblique muscle is responsible for rotating the eyeball.
- The ciliary muscle is a circular ring structure of muscle that is attached all the way around the eye lens. The ciliary muscle can change the shape of the crystalline eye lens by stretching it at the edges. It is attached to the lens by zonules that are ligament fibers that can be tight or loose.

Hence, The correct answer is option (D).

Note: When you are looking at a near object, the eye lens needs to become more rounded at the central surface in order to focus the light rays. This ability of ciliary muscle to change focus for close-up objects is known as accommodation.