Apparatus for generating and displaying visual acuity targets

摘要

First and second electro-optical display devices for displaying visual acuity targets, one of which is adapted to be viewed by a patient and the other of which is adapted to be viewed by an examiner. An electronic memory is connected to the display devices containing a plurality of acuity targets stored in various orientations for presentation to the display devices. Controls are provided in an examiner's console for selecting one of a plurality of available target sizes, "zoom" increasing size or decreasing size, selecting a single or a line of multiple target characters, providing normal or reverse video presentation, changing the orientation of the target characters, and providing a blank screen. The size of the targets is varied by changing the dimensions of each of the targets about its own center and in the case of multiple targets, maintaining proportional spacing between the targets as the size of the targets vary. A control console display indicates the size of the target displayed on the display devices. The orientation control prevents identical orientation of target characters on successive presentations. A beam splitter and hood assembly are positioned in front of the patient's display device for minimizing the effects of light reflections and ambient illumination.