We had a chalk basslett with the same problem. We never treated it, I'm sad to admit. Would have been impossible to trap him at the time. Anyway, the air bubble symptom is the same. A few times, the air bubble disappeared on its own. Then the 4th or 5th time, it got cloudy & infected. The eye eventually popped. He hung low for a week or so, and we were very worried. But he came back with a super attitude, ate fantastic even with only one eye.
I'm not sure if that helps, but he did fine for a long time. We jokingly posted that we had a fish with an air leak in his head. 