Question

When the eye looks at near objects, the lens becomes more convex due to the ________
(A) Contraction of ciliary muscles
(B) Relaxation of ciliary muscles
(C) Contraction of Iris muscles
(D) Relaxation of iris muscles

Answer 1

Hint : When the eye looks at the near objects then the lens must need to become more rounded at the central surface in order to redirect the focus of the light rays and this ability to change focus for close-up objects and is known as accommodation.

Complete Step By Step Answer:
When the eyes look at nearby objects, the ciliary muscles can contract and increase the curvature of the lens and so the lens thickness. The increased curvature of the lens allows the eye to focus on the close object and accommodates for the clarity.
The option A is the correct answer.

Additional Information:
The ciliary muscle is the smooth muscle which is responsible for the lens accommodation and is contained within the ciliary body. The property of the contraction of the ciliary muscles allows the lens of the focus light onto the retina by changing its shape. The iris muscle is an adjustable thin muscle which controls the pupil diameter.

Note :
During the accommodation of light rays and the eye vision, the crystalline lens changes shape to target the near or far targets. Always remember the difference between the accommodation to view the near and far objects. When the eye looks at the far and away objects, the muscles relax and the focus of the lens changes to an object further away for the accommodation.