Skew deviation is an unusual ocular deviation (strabismus), wherein the eyes move upward (hypertropia) in opposite directions. Skew deviation is caused by abnormal prenuclear vestibular input to the ocular motor nuclei, most commonly due to brainstem or cerebellar stroke.

What is a skew deviation?

Skew deviation is a vertical strabismus caused by supranuclear lesions. It is often associated with ocular torsion and head tilt, which together constitute the ocular tilt reaction. ^1–4. Skew deviation is often the initial manifestation of diseases that affect the brainstem, cerebellum, or peripheral vestibular system.

What is eye skew?

Skew deviation is characterized as an acquired vertical misalignment of the eyes that is not due to any single muscle or ocular motor nerve. It is typically a comitant hypertropia but can be incomitant.