Final answer:
The nurse's initial question should be to ask the client to describe the events leading to the eye injury, as this information is crucial for immediate treatment.
Step-by-step explanation:
When a client arrives at the emergency department following an eye injury due to an acidic substance, the initial question a nurse should ask is: "Can you describe the events surrounding the injury?" This question is essential because it helps to assess the cause, type of substance involved, and the immediacy of the situation, which are critical for immediate and effective treatment.
Questions about pain medication, history of eye injuries, or recent changes in vision, while potentially relevant later, are not the immediate priority given the acute nature of the situation.