Anticompensatory eye position ("contraversion") in optokinetic nystagmus.

The quick phases of full-field optokinetic nystagmus (OKN) not only reset the eyes, but also move them in an anticompensatory direction (that is, in the opposite direction to stimulus movement, “contraversion”).1–7 Although recognized as an oculomotor phenomenon, contraversion is poorly understood, and it has been suggested as a strategy for directing the line of sight into the visual field from which motion is originating.5–7 We have previously observed extreme contraversion in patients with absent smooth pursuit and a leaky eye position integrator.8 In this study we examined contraversion in healthy adults and propose a model for this behaviour based on observation from a clinical group.