Which of the following is a symptom of a stroke that involves the pupils?

A symptom of a stroke that involves the pupils being of unequal size is significant because it indicates a potential neurological emergency. This condition, known as anisocoria, can suggest pressure on the brain from swelling or bleeding, which is often associated with a stroke. When one pupil is larger than the other, it could indicate that one side of the brain is affected more severely, which can have serious implications for the individual's prognosis and treatment needs.

The other symptoms related to pupils, such as constricted pupils, overly dilated pupils, or non-reactive pupils, may occur in various other medical conditions but are not specifically indicative of a stroke. These other conditions can involve different mechanisms that do not relate to the acute vascular issues seen in strokes, making unequal pupil size a more telling sign in regards to this particular emergency. Recognizing anisocoria as a symptom of a stroke allows for quicker identification and response, which is crucial for preserving brain function and improving patient outcomes.