Medical Mystery of the Week

Because of the COVID19 pandemic, you are practicing telemedicine. You are shown a video of the eye movements of a 35-year-old man. What is your diagnosis, what test(s) do you recommend to confirm your suspicions, and what treatment, if any, do you recommend?

DIAGNOSIS: Intraocular ophthalmoplegia (IOP) in a patient with multiple sclerosis. IOP is characterized by impaired adduction on horizontal gaze coupled with a paradoxically normal  adduction with accomodation. Seen most commonly in patients with multiple sclerosis, the lesion(s), which involve the medial longitudinal fasciculus (MLF), can be unilateral or, as in the presented case, bilateral. The MLF coordinates lateral gaze (lateral rectus, cranial nerve VI) with contralateral medial gaze (medial rectus, cranial nerve III). You can see on the video that this coordination is lost bilaterally, giving the patient "crazy eyes" on horizontal gazing. The treatment is directed toward the underlying cause - in this case, multiple sclerosis.