[Strabismus induced by peripheral vestibular lesions]

Little attention has been paid in the ophthalmological literature to strabismus resulting from lesions located in the peripheral vestibular system. However, this phenomenon is commonly encountered in clinical practice. As a rule, this kind of strabismus shows a prominent vertical component. It is generally combined with a change in perception of verticality, conjugate cyclotorsion of the eyes, and head tilt. This association is known as "ocular tilt reaction". It occurs in a number of clinical settings which are believed to be related with alteration in the otolithical and/or vertical semicircular canal pathways. Strabismus occurring as a feature of ocular tilt reaction might result from different mechanisms according to the location of the lesion, e.g. in the utricles, in the midbrain tegmentum, and in the dorso-lateral medulla oblongata. This phenomenon is illustrated here with the report of a patient suffering from Ménière disease, who underwent selective vestibular neurectomy. Methods of ophthalmological evaluation in such cases is described.