To evaluate the clinical features and natural course of sixth cranial nerve palsy.

We reviewed the medical records of 50 patients who were diagnosed with sixth nerve palsy from January 2000 to December 2006 to analyze the age of onset, etiology, recovery, and natural course of this disease.

The mean age at onset was 43.2 years old. Vascular disease (n=17, 34.0%) was the most common cause of sixth cranial nerve palsy, followed by undetermined causes (n=14, 28.0%), trauma (n=10, 20.0%), and neoplasm (n=3, 6.0%). According to age group, vascular disease (n=7, 46.7%) was the most common cause in patients in their fifties and sixties, and trauma and undetermined causes (n=10, 76.9%) were the most common causes of this disease in patients in their twenties and thirties. Of the 40 patients who were followed up for more than 6 months, 28 (70.0%) showed improvement of paresis and 26 (65.0%) achieved complete recovery. The mean period to recovery was 3.7 months. No significant differences were observed in sex, age, laterality, and etiology between non-recovered and completely-recovered patients, but completely-recovered patients showed a significantly smaller initial angle of deviation than non-recovered patients.

Vascular disease was the most common etiology of sixth nerve palsy. Sixty-five percent of patients showed spontaneous complete recovery, and completely-recovered patients showed a significantly smaller initial angle of deviation compared to that of non-recovered patients.