[Replacement of the Herschel revolving double prism and the Maddox double wing with a prismatic glass for testing of heterophoria].

After the short summary of investigation methods of latent Squint the authors report about the method using the standard Trial Frame Okula and prism with a power of 16 pdpt, with Maddox lens from common trial case Okula. This method is used for an indication of magnitude of latent Squint for a short and a long distance. After the meaning of the authors is exoforia for a short distance one of the most frequent causes of muscular asthenopic disorders.