Superior oblique myokymia is a neurological disorder affecting vision and was named by Hoyt and Keane in 1970.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 course is benign and is not commonly associated with other disorders. Causes
In 1983, Bringewald postulated that superior oblique myokymia resulted from vascular compression of the trochlear nerve (fourth cranial nerve), which controls the action of the superior oblique muscle in the eye. By 1998, there had been only one reported case of compression of the trochlear nerve by vessels. 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. Diagnosis
Treatment
Treatment can include pharmaceutical or surgical means. The drug carbamazepine (Tegretol) has been used successfully. Other drugs with variable success include gabapentin and, recently, memantine. Successful surgery options include superior oblique tenectomy accompanied by inferior oblique myectomy. 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. "Samii et al. and Scharwey and Samii described a patient who had superior oblique myokymia for 17 years.
A small assessment of sustained release of 0.4 mg belladonna alkaloids and ~60 mg phenobarbital (1 grain) was performed in patients with functional GI disorders (i.e., gastric hyperacidity, dyspepsia, pyrosis, gas pains and epigastric distress. Overall, 23 of 25 patients reported complete or significant relief of symptoms. Hock also examined the effect of 0.25 mg belladonna alkaloids and 50 mg phenobarbital sustained release formulation in 82 clinical practice patients with various gastrointestinal disturbances including “functional distress” over 27 months. Of the 82 total patients, 33 patients reported a 50-75% and 20 reported a 75-100% improvement. There were specific reports of improvements in pain and bowel habits in over half of the patients. One of the earliest randomized double-blind clinical trials of belladonna alkaloids + phenobarbital was in 1959 by Lichstein et al. The study involved 75 patients with unstable bowel (whose symptoms are typical or similar to a current diagnosis of IBS) to investigate the combination therapy of an anticholinergic with the addition of phenobarbital against placebo over 15 months. Of these patients, 20 were treated with placebo, 43 were treated with 50 mg phenobarbital in combination with 0.25 mg Belladonna alkaloids, and 12 received both therapies (patients who lacked a response were switched therapy). Of those receiving the belladonna alkaloids / phenobarbital only, 75.6% reported a mean improvement (2+ or better) in all categories. Among the placebo patients only, only 29.8% reported mean improvement in symptoms.