A patient shows no effect when a light shines in the right eye,but shining a light into the left eye causes both pupils (right and left)to constrict.This could be caused by a lesion on the ______ nerve.
A)optic
B)trochlear
C)trigeminal
D)facial

Question

Quizplus · Accepted Answer

The optic nerve is responsible for transmitting visual information from the retina to the brain. In this scenario, the lack of response when light is shone in the right eye suggests a problem with the sensory input from that eye, which is carried by the optic nerve. The fact that shining light in the left eye causes both pupils to constrict indicates that the efferent pathways (those controlling pupil constriction) are intact, pointing to an issue with the sensory input from the right eye, hence a lesion on the optic nerve of the right eye.

A Patient Shows No Effect When a Light Shines in the Right