The purpose of our study was to evaluate the cause of acquired third, fourth, and sixth nerve palsy while also establishing recovery rates and important factors for recovery.

A retrospective chart review was performed for 92 patients who visited the ophthalmologic department of Konyang University Hospital with acquired third, fourth, and sixth nerve palsy from March 2015 to February 2016. Recovery rates and factors for recovery were evaluated in only 66 patients who received first ocular exam within 2 weeks of onset and who were followed up for at least 6 months. Complete recovery was defined as both complete recovery of the angle of deviation and the restoration of eye movement in all directions. For the degree of ocular motor restriction, -4 was defined as not crossing the midline and -2 was defined as 50% eye movement. The degree of ocular motor restriction was analyzed from -1/2 to 4.

The fourth nerve was affected most frequently (n = 37, 40.2%), followed by the sixth cranial nerve (n = 33, 35.9%), the third cranial nerve (n = 18, 19.6%), and a combination of 2 or more cranial nerves (n = 4, 4.3%). Vasculopathy (n = 44, 47.8%) was the most common etiology, followed by trauma (n = 14, 15.2%), idiopathic (n = 13, 14.1%), inflammation(n = 10, 10.9%), neoplasm (n = 9, 9.8%), and aneurysm (n = 2, 2.2%). Complete recovery rate occurred for 66.7% (n = 44) of patients, and the overall recovery rate (i.e., at least partial recovery) was 86.3% (n = 57). Significant factors for complete recovery were the initial deviation angle and the limitation of extraocular movement ( p < 0.001, p = 0.005, respectively, according to univariate analysis).

In this study, paralytic strabismus due to vasculopathy was the most common etiology, and a lower degree of initial deviation resulted in an improved complete recovery rate. In addition, a high overall recovery rate was possible through quick diagnosis and early treatment of cranial nerve palsy.