Compared to viewing a distant object, viewing an object held within 5 cm of the eye requires a lens that
A) has been flattened, as a result of contraction of the ciliary muscles.
B) has been made more spherical, as a result of contraction of the ciliary muscles.
C) has been flattened, as a result of relaxation of the ciliary muscles.
D) has been made more spherical, as a result of relaxation of the ciliary muscles.
E) does not change its shape.

Question

Quizplus · Accepted Answer

Viewing an object held within 5 cm of the eye requires more convergence of light rays toward the retina than viewing a distant object. The ciliary muscles contract to adjust the shape of the lens for closer focus, making it more spherical in shape in order to refract the light more strongly. This enables the lens to bend the light rays to a greater degree, so that they converge at the correct focal point in the retina. Therefore, the correct answer is B, which states that the lens has been made more spherical as a result of contraction of the ciliary muscles.

Compared to Viewing a Distant Object, Viewing an Object Held