Superior Oblique Myokymia

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Identifier Superior_Oblique_myokymia
Title Superior Oblique Myokymia
Subject Pathology; Myokymia; Anatomy
Creator Andrew G. Lee, MD, Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, TX; Professor of Ophthalmology, Weill Cornell Medicine; Aryan Pashaei-Marandi, University of Texas Medical Branch Class of 2020
Description Dr. Lee lectures medical students on superior oblique myokymia.
Transcript Today we're going to talk about superior oblique myokymia, abbreviated SOM. It's what we call a telephone diagnosis. You can hear the symptoms on the telephone, and know exactly what it is. It is characterized by a small amplitude, high frequency and intermittent motion of the eye. Because the superior oblique muscles primary action is intorsion, the patient sees this. It's monocular, which means the other eye is doing nothing. So a small amplitude, relatively high frequency, intermittent, torsional and vertical movement of one eye. You have to ask the patient does it go away if they cover either eye. If they cover the involved eye, it will go away. If they cover the other eye it will persists. It is one of the few monocular forms of nystagmus. It's not really a nystagmus. It's a microtremor of the superior oblique. What we see on the slit-lamp is we see the torsion. Because we can't see the torsion well in the circle, you can see the conjunctival vessel intort at the slit-lamp. There are some triggers. You should ask the patient to keep a diary. The most common triggers are stress, lack of sleep, and specific food or drinks. It's usually benign. If it's isolated, we don't usually image it. But you could do an MRI. There are rare cases where there is a structural lesion on the 4th nerve causing it. But in most cases, it's benign. If they have intractable symptoms, we can treat it with either a beta- blocker or carbamazepine. These are membrane stabilizing agents. Either by mouth or as a topical drop, like timolol. If they fail maximal medical therapy, you can do surgery by cutting the superior oblique and inferior oblique. We would do a SO tenectomy, cut the tendon, and a IO myectomy to cancel out the vertical effect. If you just did d a SO surgery, you would get a 4th nerve palsy iatrogenically. Most patients do not have to surgery, however. In summary, superior oblique myokymia is a intermittent, small amplitude moderate to high frequency torsional movement producing flickering, shimmering or vertical diplopia in one eye only. You can look at the slit-lamp and look at the vessel to see torsion. And you can treat it medically, and if necessary, surgery. But most people don't need anything but reassurance.
Publisher Spencer S. Eccles Health Sciences Library, University of Utah
Date 2019-02
Type Image/MovingImage
Format video/mp4
Rights Management Copyright 2019. For further information regarding the rights to this collection, please visit:
Holding Institution Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E, SLC, UT 84112-5890
Collection Neuro-ophthalmology Virtual Education Library: NOVEL
Language eng
ARK ark:/87278/s6tf499q
Setname ehsl_novel_lee
Date Created 2019-03-01
Date Modified 2020-01-14
ID 1403676
Reference URL
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