LAUSR

Binocular horizontal diplopia with a unilateral abduction deficit is often due to sixth nerve palsy. However, it can also be caused by other conditions, such as medial rectus muscle restriction in thyroid eye disease. In this chapter, we begin by reviewing the differential diagnosis of an abduction deficit. We next list the common causes of an isolated unilateral sixth nerve palsy and bilateral sixth nerve palsy. We then discuss our approach to neuroimaging for sixth nerve palsy, as this remains a controversial topic. Lastly, we discuss the prognosis and management of sixth nerve palsy, with a focus on sixth nerve palsy due to microvascular ischemia.