Superior oblique myokymia (SOM) is a relatively rare neurological disorder characterized by involuntary, rhythmic contractions or twitching of the superior oblique muscle of the eye. This muscle, located at the top and inner side of the eyeball, is responsible for rotational eye movements.
The condition typically presents with episodes of repetitive, high-frequency jerking of the affected eye. These involuntary movements may be experienced as a shimmering or vibrating sensation within the visual field, often causing transient vertical diplopia (double vision). Individuals with superior oblique myokymia may also report intermittent or persistent tilting or torsional sensation of the visual world.
The exact cause of superior oblique myokymia remains unknown, although it is believed to be related to a dysfunction in the neuromuscular control of the superior oblique muscle. Some studies have suggested that the condition may be a result of neurovascular compression or vascular loops affecting the cranial nerve that innervates the muscle.
Diagnosis of superior oblique myokymia is usually made through a thorough examination of the eye movements, with special attention paid to the superior oblique muscle. Additional diagnostic tests, such as magnetic resonance imaging (MRI), may be utilized to rule out other potential underlying causes.
Management can involve both conservative and invasive approaches. Conservative management may include prism glasses to correct the double vision or pharmacological interventions, such as oral medications or local injections, to reduce the frequency and severity of the eye movements. In severe cases that do not respond to conservative treatments, surgical interventions like superior oblique tenectomy or division may be considered as a last resort.
Overall, superior oblique myokymia is a rare eye movement disorder characterized by repetitive, involuntary contractions of the superior oblique muscle,
