Fit to fly is the same thing. Flew with a guy who was convinced we were lined up on a taxiway instead of a runway in KLAS. It is the only email I have sent on a crew member in my career and this was after several night related issues I had with him. He was told to wear his corrective lenses and that is it. Why do I know this? Because he told me that they had contacted him because a crew member ratted him out, he didn't know who the crew member was, but he told me what the "corrective action" was. Smoking hole is the only thing that gets change, period.