What does damage to Cranial Nerve III impede?

Damage to Cranial Nerve III, also known as the oculomotor nerve, primarily affects eye movement, pupil constriction, and the ability to accommodate (focus on objects at varying distances). This nerve is responsible for innervating several eye muscles that facilitate movements, as well as controlling the constriction of the pupil and the lens shape for focusing.

When this nerve is impaired, patients may experience double vision due to disrupted eye alignment, a dilated pupil that does not respond to light changes or accommodation, and difficulty focusing on objects. In contrast, other functions such as balance, spatial awareness, facial sensation, taste perception, or shoulder strength are not directly affected by the integrity of Cranial Nerve III, highlighting its specific role in ocular function.