Optokinetic nystagmus: a review of pathways, techniques and selected diagnostic applications

There are a myriad of conditions producing abnormal OKN responses. In most of these conditions the diagnosis can be made without recourse to OKN. However, in the five conditions described in this paper (suspected poor visual acuity in infants and young children, parietal lesions, subclinical internuclear ophthalmoplegia, Parinaud's syndrome, and aberrant regeneration of the third nerve) OKN can greatly facilitate the diagnosis. A review of the neural pathways of the OKN response and an explanation of the various equipment and techniques used to assess OKN are included.