Ocular Misalignment in Dizzy Patients-Something's A-Skew.

Abstract

Both central (eg, brain stem, cerebellum) and peripheral (eg, vestibular, fourth cranial nerve palsy) etiologies can cause a vertical misalignment between the eyes with a resultant vertical diplopia. A vertical binocular misalignment may be due to a skew deviation, which is a nonparalytic vertical ocular misalignment due to roll plane imbalance in the graviceptive pathways. A skew deviation may be 1 component of the ocular tilt reaction. The purposes of this article are (1) to understand the pathophysiology of a skew deviation/ocular tilt reaction and (2) to be familiar with the examination techniques used to diagnose a skew and to differentiate it from mimics such as a fourth cranial nerve palsy. The presence of a skew deviation usually indicates a brain stem or cerebellar localization. Vertical ocular misalignment is easily missed when observing the resting eye position alone. Physical therapists treating patients with vestibular pathology from central or peripheral causes should screen for vertical binocular disorders.