Eye motion kinetics in moving target pursuit--a system for detection of oculomotor abnormalities in neurological disorders.

An electrooculographic system for quantitive study of tracking eye motion is described. The tracking target is a projected spot of light which moves under computer control with different operator selectable constant accelerations. A single FORTRAN program with eleven subroutines, running on a PDP 11/40 computer in 22 K of memory, controls data collection and data analysis, as well as target movement. A number of quantitative parameters are extracted from the data, including smooth pursuit velocity, the correlation in movement between the two eyes and the maximum eye-target spot 'phase' difference in degrees. The relationship between smooth pursuit and saccadic eye movements can be visualised by storage and display of the instantaneous eye velocity during tracking manoeuvres. The system has proven very useful as an aid to diagnosis of some neurological disorders, particularly multiple sclerosis.