The actual illuminated spectacle examination is performed in a dark room or a heavily darkened room. The internal illumination of the spectacles breaks the optical contact of the patient with his surroundings (elimination of the fixation that prevents nystagmus). However, brightly illuminated eyes are particularly easy to observe under magnifying spectacles. In many cases, abnormal nystagmus processes can be detected by looking straight ahead which cannot be detected reliably or at all without glasses. With the glasses open and the room light on, the eye can be observed with preserved fixation, e.g. with the Hallpike technique of thermal examination. By switching off the room light and folding down the spectacle lenses, it is possible to quickly switch to an actual illuminated spectacle examination by switching off the fixation. Power for the nystagmus spectacles is provided by either the DEHAG battery holder type 504 or the plug-in power supply type 506 (both not supplied). The DEHAG battery holder is powered by three 1.5 volt C size LR14/AM-2 batteries (baby batteries). The adjustable battery holder handle allows you to adjust the brightness individually by turning the switch slightly. The plug-in power supply can be connected via a standard household socket (100-240V/AC, 50/60Hz)
