Superior oblique myokymia
Superior oblique myokymia (SOM) is a neurological disorder affecting vision that presents as repeated, brief episodes of movement, shimmering or shaking of the vision of one eye.
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The condition was named by Hoyt and Keane in 1970.
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named by Hoyt and Keane in 1970
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Onset usually occurs in adulthood and the cause is benign.
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Onset usually occurs in adulthood, and the cause is benign and is not commonly associated with other disorders.
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It may result from vascular compression of the trochlear nerve.
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superior oblique myokymia resulted from vascular compression of the trochlear nerve (fourth cranial nerve)
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Patients experience repeated, brief episodes of movement, shimmering or shaking of the vision of one eye.
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repeated, brief episodes of movement, shimmering or shaking of the vision of one eye
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Symptoms can include a feeling of the eye trembling or vertical/tilted vision.
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a feeling of the eye trembling, or vertical/tilted vision
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Visuo-perceptual symptoms include diplopia, monocular oscillopsia, or monocular reading impairment.
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Visuo-perceptual, i.e., diplopia, monocular oscillopsia, or monocular reading impairment
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Ocular motor symptoms include a sensation of involuntary monocular eye-twitching or movement.
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Ocular motor, i.e., a sensation of involuntary monocular eye-twitching/movement
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Vestibular-postural symptoms include gait instability or dizziness.
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Vestibular-postural, i.e., gait instability or dizziness
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Diagnosis is most often made by the elimination of other conditions, disorders or diseases.
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Diagnosis is most often made by the elimination of other conditions, disorders or diseases.
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Definite SOM diagnosis requires at least ten episodes with symptoms from at least 2 out of 3 symptom categories.
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At least ten episodes with symptoms from at least 2 out of the 3 following symptom categories
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Episodes must have a duration of less than 1 minute.
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Duration less than 1 minute
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Diagnosis involves videooculographic or clinical confirmation of monocular vertical–torsional nystagmus.
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Videooculographic or clinical confirmation of monocular vertical–torsional nystagmus
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Symptoms must not be better accounted for by any other vestibular or neuro-ophthalmological disorder, especially vestibular paroxysmia.
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the symptoms must not be better accounted for by any other vestibular or neuro-ophthalmological disorder, especially not by vestibular paroxysmia
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Treatment can include pharmaceutical or surgical means.
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Treatment can include pharmaceutical or surgical means.
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The drug carbamazepine (Tegretol) has been used successfully.
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The drug carbamazepine (Tegretol) has been used successfully.
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Successful surgery options include superior oblique tenectomy accompanied by inferior oblique myectomy.
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Successful surgery options include superior oblique tenectomy accompanied by inferior oblique myectomy.
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Invasive craniotomy surgical procedures should be justified only by intractable and absolutely unbearable symptoms.
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invasive craniotomy surgical procedures should be justified only by the presence of intractable and absolutely unbearable symptoms
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Interposition of a Teflon pad between the trochlear nerve and compressing vessels has led to remission.
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The interposition of a Teflon pad between the trochlear nerve and a compressing artery and vein at the nerve's exit from the midbrain led to a remission lasting for a follow-up of 22 months.
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Symptoms must not be better accounted for by other vestibular or neuro-ophthalmological disorders, especially vestibular paroxysmia.
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the symptoms must not be better accounted for by any other vestibular or neuro-ophthalmological disorder, especially not by vestibular paroxysmia
The cause is benign and not commonly associated with other disorders; surgical interposition of a Teflon pad led to a remission lasting for a follow-up of 22 months in one case.
| Superior oblique myokymia | |
|---|---|
| 6 = Superior oblique muscle | |
| Specialty | Neurology |
Superior oblique myokymia (SOM) is a neurological disorder affecting vision and was named by Hoyt and Keane in 1970.[1]
It is a condition that presents as repeated, brief episodes of movement, shimmering or shaking of the vision of one eye, a feeling of the eye trembling, or vertical/tilted vision. It can present as one or more of these symptoms. Diagnosis is most often made by the elimination of other conditions, disorders or diseases. Onset usually occurs in adulthood, and the cause is benign and is not commonly associated with other disorders.
In 1983, Bringewald postulated that superior oblique myokymia resulted from of the trochlear nerve (fourth cranial nerve), which controls the action of the superior oblique muscle in the eye.[2] By 1998, there had been only one reported case of compression of the trochlear nerve by vessels.[3][4] More recently, magnetic resonance imaging experiments have shown that neurovascular compression at the root exit zone of the trochlear nerve can result in superior oblique myokymia.[5]
Only recently, diagnostic criteria were proposed.[6] According to these criteria, definite SOM diagnosis requires:
- At least ten episodes with symptoms from at least 2 out of the 3 following symptom categories:
- Visuo-perceptual, i.e., diplopia, monocular oscillopsia, or monocular reading impairment
- Ocular motor, i.e., a sensation of involuntary monocular eye-twitching/movement
- Vestibular-postural, i.e., gait instability or dizziness
- Stereotyped phenomenology in a particular patient
- Duration less than 1 minute
- Videooculographic or clinical confirmation of monocular vertical–torsional nystagmus, typically increased by hyperventilation, triggered by accommodation, and more pronounced in downward or sideward gaze
- Response to treatment with anticonvulsant medication (carbamazepine, oxcarbazepine, lacosamide) or topical beta blockers (levobunolol, timolol, betaxolol, propranolol)
Importantly, the symptoms must not be better accounted for by any other vestibular or neuro-ophthalmological disorder, especially not by vestibular paroxysmia.
Treatment can include pharmaceutical or surgical means. The drug carbamazepine (Tegretol) has been used successfully. Other drugs with variable success include gabapentin and, recently,[when?] memantine. Successful surgery options include superior oblique tenectomy accompanied by inferior oblique myectomy.[7] However, "[o]verall, the bulk of the ophthalmic literature would agree with the viewpoint that invasive craniotomy surgical procedures should be justified only by the presence of intractable and absolutely unbearable symptoms."[8]
Samii et al.[3] and Scharwey and Samii[4] described a patient who had superior oblique myokymia for 17 years. The interposition of a Teflon pad between the trochlear nerve and a compressing artery and vein at the nerve's exit from the midbrain led to a remission lasting for a follow-up of 22 months.[citation needed]
- ↑ Hoyt WF, Keane JR (October 1970). "Superior oblique myokymia. Report and discussion on five cases of benign intermittent uniocular microtremor". Arch. Ophthalmol. 84 (4): 461–7. doi:10.1001/archopht.1970.00990040463011. PMID 5492451.
- ↑ Bringewald PR (August 1983). "Superior oblique myokymia". Arch. Neurol. 40 (8): 526. doi:10.1001/archneur.1983.04210070066021. PMID 6870617.
- 1 2 Samii M, Rosahl SK, Carvalho GA, Krzizok T (1998). "Microvascular decompression for superior oblique myokymia: first experience. Case report". J. Neurosurg. 89 (6): 1020–24. doi:10.3171/jns.1998.89.6.1020. PMID 9833830.
- 1 2 Scharwey K, Krzizok T, Samii M, Rosahl SK, Kaufmann H (2000). "Remission of superior oblique myokymia after microvascular decompression". Ophthalmologica. 214 (6): 426–28. doi:10.1159/000027537. PMID 11054004. S2CID 35862822.
- ↑ Yousry I, Dieterich M, Naidich TP, Schmid UD, Yousry TA (March 2002). "Superior oblique myokymia: magnetic resonance imaging support for the neurovascular compression hypothesis". Ann. Neurol. 51 (3): 361–68. doi:10.1002/ana.10118. PMID 11891831. S2CID 23905926.
- ↑ J. Gerb, A. Zwergal, N. Lehrer, N. Hansel, M. Näher, F. Thiessen, M. Dieterich, D. Huppert: Superior oblique myokymia: diagnostic criteria and long-term outcome. In: Journal of neurology. Band 273, Nummer 4, April 2026, S. , doi:10.1007/s00415-026-13773-6, PMID 41922524, PMC 1304356.
- ↑ "Superior Oblique Myokymia 379.58". Retrieved 2007-06-25.
- ↑ J Optom. 2014; 7:68–74 Vol. 7 Num. 2 doi:10.1016/j.optom.2013.06.004