LESIONS

A Guide to Localisation in Neurology

Case 18 - Double vision and jumping eyes

Case

A 50 year old man presented with double vision.

He had been well that morning, then developed abrupt-onset double vision, with vertical and horizontal separation of two images. If he closed one eye he would only see a single image. He felt dizzy, with a mild sensation of vertigo, but was able to walk and to perform tasks despite this. He had no other focal symptoms, including changes to speech or weakness in the face or limbs.

His background included type 1 diabetes and hypertension, and he took insulin and two blood-pressure lowering medicines.

On examination he had:

• Upward deviation of the right eye (i.e. hypertropia), which returned to a central position when the left eye was covered
• Upbeat and anticlockwise-beating (from the examiner’s perspective) torsional nystagmus in both eyes
• Inability to adduct the right eye when attempting leftward gaze. The left eye could abduct, but had left-beating nystagmus during this.
• He could still adduct both eyes towards the midline on convergence testing. He did not have limitation in any other direction of gaze.

The rest of the exam was normal, including other cranial nerve testing and normal power and coordination in the limbs.