[Computer-assisted provocation and detection of optokinetic nystagmus]

A computer-controlled system for the automatic induction, registration, and analysis of optokinetic nystagmus is presented. On a high-resolution computer video monitor, a horizontally moving pattern of vertical stripes of equal size and distance is displayed. Stimulus size, velocity, and direction of movement are computer-controlled and variable. Exposure to this display induces horizontal optokinetic nystagmus in the patient. The patient's eye movements are registered by an infrared non-contact limbus-tracker system and transferred to the computer in a digitized format. With a specifically developed computer program the pursuit eye movements are detected and analyzed for amplitude, duration, and velocity and may be displayed on a second monitor. Simultaneously, the congruence of the direction of the stimulus and of the direction of the eye movement are automatically supervised and quantified by an "acceptance coefficient." The first clinical studies with healthy experimentees showed that for each stimulus size a certain stimulus velocity exists that provides maximal nystagmus provocation. Smaller stimulus sizes require slower stimulus velocities. Future developments of the system will allow applications in other fields of nystagmus research and in the accessment of objective visual acuity.