Final answer:
To check a child's trochlear nerve function, a nurse would test the eye movement by asking the child to follow a pen with their eyes. This checks for conjugate movements and coordination controlled by the trochlear nerve and associated systems.
Step-by-step explanation:
When checking a child's trochlear nerve function, a nurse would perform the data collection technique of having the child track the tip of a pen with their eyes as it is passed through the visual field. The trochlear nerve is responsible for controlling the superior oblique muscle of the eye, which is involved in rotary and downward movement. The nurse is looking for smooth, coordinated movement of the eyes, known as conjugate movements, which indicates proper function of the nerve, the related nuclei, and the medial longitudinal fasciculus (MLF).
Failure of one eye to abduct while the other adducts in a horizontal movement is referred to as internuclear ophthalmoplegia, which can lead to diplopia, or double vision. This condition suggests issues with the coordination of eye movements, potentially relating to the trochlear nerve among others.