Optokinetic nystagmus is a series of involuntary eye movements made in response to a moving stimulus here shown in the top left of the
frame, drifting to the right. Notice the eye repeatedly tracks the image by moving to the right, before abruptly making a large corrective movement to the left. The image embedded in the top is the observers view of the stimulus demonstrating that these eye movements partially stabilise the moving image on the retina. Finally the graph at the bottom plots eye-position over time with red points showing rightwards eye movements and green points, leftwards eye movements. The repeating pattern of track-and-correct eye movements forms a “sawtooth” pattern characteristic of optokientic nystagmus.