Based on the context and the answer, generate a question. 

Context: So lately , the headaches and nausea and dizziness have been coming back . I had no explanation . As far as I knew , I could still see well with my glasses .

Answer:

The uncorrected vision requires an immense amount of effort and straining , which manifests as physical symptoms



What could the glasses have to do with these physical symptoms that the speaker is experiencing ?