Inappropriate prescription of prism glasses for obligate fixation disparity measured with the Pola test

In the subjective measurement of fixation disparity (FD), the subject sees and fuses contours presented in the peripheral macular areas of both eyes ('fusion loek', a square for instanee). The pointing direction of the foveolae of both eyes relative to each other is determined by means of two haploscopically seen objects presented in the central visual field (Fig. la). ...