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

Background and Purpose: 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. Summary of Key Points: 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. Recommendations for Clinical Practice: Physical therapists treating patients with vestibular pathology from central or peripheral causes should screen for vertical binocular disorders.