When i read, i switch up letters making the words on the paper different words. do i need glasses?

Evaluation.: If this is relatively new it could be a visual problem or a neurologic issue. If this is a chronic condition it might not be due to vision. I suggest that you start by letting your family doctor know & getting your eyes checked. If vision isn't the issue than a more comprehensive assessment should be done. Take care.

Dyslexia: Usually when someone consistently does that it is possible they have dyslexia which is a condition where you switch words. Sometimes when people are tired they do that but then it is not consistent