Sudden-onset trochlear nerve palsy: clinical characteristics and treatment implications.

Purpose: To identify clinical characteristics, etiologies, and treatment implications of sudden-onset, acquired cases of superior oblique palsy.

Methods: The medical records of patients diagnosed with trochlear nerve palsy between January 2010 and January 2018 were reviewed retrospectively to identify cases of acquired trochlear nerve palsy with a specific date of onset of acute symptoms or specific causative incident. Patients with congenital palsies or an uncertain date of onset, history of other strabismus, concomitant oculomotor or abducens nerve palsies, or history of strabismus surgery were excluded.