[Johann Sebastian Bach's disease and his bizarre english physician].

Johann Sebastian Bach suffered during the last year of his life of a progressive visual defect despite two operations done by a famous but quite controversial English ocular surgeon of that time. The exact diagnosis of his ocular problems is unclear but cataracts and complicated glaucoma seem the most plausible. A septic complication following the ocular surgery could have weakened Bach's health leading to his death only three months after the last intervention. In this paper diverse less known aspects of Bach's disease and life are reported.