[Binocular triplopia induced by weak prisms (author's transl)].

The prescription of weak prisms may induce monocular diplopia or binocular triplopia. The monocular double image is due to internal reflexion at the glass-air interface. The intensity of the secondary image is very weak (0.2% of the primary image). The prismatic deflection of the secondary image is six times the deflection of the primage image.