This document discusses vertical deviation, which refers to a vertical misalignment of the eyes. Vertical deviations can be classified as concomitant or incomitant. Common causes of vertical strabismus include restrictive conditions like Duane syndrome or mechanical restrictions from scarring. The document then discusses specific nerve palsies - third nerve palsy causes ptosis and eye positioning issues. Fourth nerve palsy presents with hypertropia in right gaze. Sixth nerve palsy causes esotropia and limited abduction. Treatment depends on the underlying cause but may include occlusion, prisms, botulinum toxin injections, or strabismus surgery.