Walsh & Hoyt: Classification of Nystagmus Based on Pathogenesis

Our classification of nystagmus starts by relating the various forms of nystagmus to disorders of visual fixation, the vestibulo-ocular reflex, or the mechanism for eccentric gazeholding. In addition, the adaptive processes that optimize these eye movements may be affected by disease, and we discuss these recalibration mechanisms as we deal with each class of nystagmus. Some forms of nystagmus can be better explained than others by this scheme. Nonetheless, our goal is to provide current hypotheses for nystagmus and saccadic intrusions whenever possible. Some hypotheses are backed by substantial evidence, whereas others are more tentative. The justification for this approach is that it provides explanations for clinical findings when knowledge allows, but also provides provisional hypotheses for other disorders that can be tested in future studies.