Clinical Reasoning: A 36-year-old man with vertical diplopia

Abstract

A 36-year-old man with Von Hippel-Lindau syndrome presented with binocular vertical diplopia following suboccipital craniotomy for resection of a cerebellar hemangioblastoma. His diplopia was worse in left gaze. He was effectively treated with a 6-diopter base-down prism in the right eye. With-out spontaneous improvement after 10 months of using prisms, he desired an alternative to prism correction. ### Question for consideration: 1. What features of the examination will help determine the cause of vertical diplopia? A detailed neuro-ophthalmologic history and examination is critical for evaluation of double vision (table). First, it should be established whether double vision is monocular (persists with the fellow eye closed) or binocular (abates with one eye closed). Binocular diplopia results when misaligned eyes relay contradictory visuospatial information; it therefore does not occur when viewing through one eye only. Examination should include observation of abnormal posture, such as a head tilt or head turn that the patient may use to minimize symptoms; these may also be evident on old photographs. Ocular ductions (movements of each eye individually) and versions (movements of the eyes together) should be carefully examined in all directions, to identify abnormalities of muscle weakness or overaction.1 Weakness in a particular direction of gaze may be partial or complete, and may result from dysfunction at the level of the cranial nerve, eye muscle, or neuromuscular junction. Muscle overaction in a direction of gaze often signifies compensation for a long-standing or congenital process. The possibility of mechanical restriction (for example, from an orbital mass or extraocular muscle fibrosis) may be tested by evaluating forced ductions, using a cotton-tipped applicator or ophthalmic forceps to rotate the globe after applying topical anesthesia. In patients with nonrestrictive paresis, the eye can be moved the full extent of a normal duction. View this table: Table Examination techniques in the diagnosis of vertical diplopia It is common …