Final answer:
The cranial nerves tested when assessing the eyes include the oculomotor, trochlear, abducens, and optic nerves. They are evaluated through tests that include tracking a visual target and assessing the vestibulo-ocular reflex.
Step-by-step explanation:
Cranial Nerves Tested When Assessing the Eyes
When assessing the eyes during a cranial nerve exam, several cranial nerves responsible for eye movement and vision are being tested. These include the oculomotor (CN III), trochlear (CN IV), and abducens (CN VI) nerves. These nerves control the extraocular muscles and are integral to coordinated eye movement. The optic nerve (CN II) is also tested because it is responsible for vision.
Tests used to assess these nerves often include having the patient follow a visual target, like the tip of a pen, which assesses conjugate gaze. This is done through the visual field ending with an approach toward the face to test for convergence and accommodation. A normal finding would be the smooth, coordinated movement of both eyes in all directions.
The vestibulo-ocular reflex, involving the vestibulocochlear nerve (CN VIII), helps stabilize gaze during head movements by coordinating equilibrium sensations with eye movement systems. A normal reflex will result in a stabilized gaze even when the head is moving.