Question

A person sees an object closer to his eyes. What changes will take place in his eyes?

• A. The pupil size will expand
• B. The ciliary muscles will contract
• C. The focal length of the eye lens will increase
• D. The light entering the eye will be more

Answer 1

Answer: (B)

The ciliary muscles will contract

Answer 2

When a person sees an object closer to their eyes, the eye undergoes a process called accommodation to bring the image into focus on the retina.

• Pupil Size: The pupil typically constricts (miosis) to increase the depth of field and reduce spherical aberration when viewing a close object.

• Ciliary Muscles: To focus on a nearby object, the eye lens needs to become more convex (thicker) to increase its refractive power and decrease its focal length. This is achieved when the ciliary muscles contract, which reduces the tension on the suspensory ligaments.

• Focal Length: For focusing on a nearby object, the eye lens becomes more convex and thicker. A thicker, more convex lens has a shorter focal length.

• Light Entering the Eye: The pupil tends to constrict when focusing on a near object, leading to less light entering the eye.

Therefore, the only correct change is that the ciliary muscles will contract.