system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do doctors always check the eyes of a patient with a light when they are unconscious?
gpt
To see how the pupils change in response to light stimulus. They should shrink, and both eyes should do so equally.

Failure to respond, delay in responding, or asymmetry in response are all signs of potential neurological issues, like drugs, bleeding or damage.