[2] He studied at the Anatomical and Surgical School at Sacra Infermeria in Valletta (Malta), the Santo Spirito Hospital in Rome (Italy), the University of Vienna (Austria).

His appointment to the post by the Empress Maria Theresa of Austria was made in consideration of his "special skill in eye diseases as well as his aptitude in finer anatomy".

Barth also opened a private nursing home and the first public eye clinic in the Vienna General Hospital in 1784, wherein he operated on cases of cataract.

1819) and an operative text on cataract removal Etwas uber die Ausziehung des graven Staars fur den genubten Operateur (Vienna, 1797, Salzburg, 1797).

In 1827, Dr Stefano Zerafa described Joseph Barth as "a man of great merits, Maltese citizen, Chief Physician and Counsellor to Her Sacred Majesty, Professor of Sublime Anatomy and Physiology in the Academy of Vienna, undoubtedly the first among ophthalmologists."