This bachelor thesis deals with the simple binokular vision, its degrees (superposition, fusion, stereopsis) and the investigation methodes which are used in orthoptics. Examinations and test results – both physiological and pathological – are presented here. For a better understanding of the diagnostic procedures, the basic facts about simple binocular vision and its pathologies (suppression, diplopia), as well as methods on which investigative procedures are based, are summarized.