[Home orthoptic practice by means of stereoprojection]

As we know polarisationhaploscopy is a method of dividing right and left side vision. Modern visusprojectors have this installed for the examination of binocular vision. A method of stereoprojection on a large silver screen is demonstrated, until now this was not done on account of technical difficulties. With this new method principally the same examinations are possible as with the phase-difference-haploscope. The projected picture is a fusionimpuls of brilliant picture quality. Fusion and stereobjects with differently near foreground motives that were photographed in differing distances and with different stereobasis as well as numerous projection variations give a wide spectrum for practicing. The slides should be taken in the known surroundings of the children so that they show more interest in practice than when using the prism bar. The optimal circumstances for stereoprojection and orthoptic practices relying on literature are shown. The position of the geometric pictures and circumstances of orthomorphe and heteromorphe pictures are demonstrated by graphics. A convergent systemposition always leads to a heteromorphe projection with a shortening of the stereoscopic range. The perception frequently differs from the objective geometric construction. The normal stereoprojection and orthoptic practices are not disturbed by the objective and described pictureblurring. Examples demonstrate how to set up the system for a defined squintangle as well as how to find the reached fusionspan. Using a third projector enables a continuous change from uncrossed dispertion to crossed without change of slides.