Daniel R. Gold, DO, Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine
This is a 70-year-old woman with HTN and diabetes who presented with horizontal diplopia for several weeks, worse in right gaze. There was a very subtle abduction paresis OD with full motility elsewhere. With cover-uncover testing, there was a small esotropia in right gaze (esodeviation seen with alternate cover testing in this video), and with alternate cover testing there was a very subtle esophoria in primary gaze at distance, and she was orthophoric in left gaze. MRI showed a small subacute stroke involving the right 6th nerve fascicle within the pons. There was evidence of fibromuscular dysplasia involving the right vertebral artery, and this was thought to be the most likely cause of her pontine stroke. Commonly in patients with diplopia, motility is normal or near normal, so that localization is not possible without measurements of alignment. Alternate cover, cover-uncover testing and/or Maddox rod testing should be performed.
Spencer S. Eccles Health Sciences Library, University of Utah