336 INTRODUCTION Superior oblique myokymia (SOM) is a rare ocular motility disorder characterized by unilateral par- oxysmal oscillopsia and micro-tremor. Intermittent contractions of the superior oblique muscle cause torsional and vertical eye movements mainly in the primary gaze position and in abduction. Although Duane 1 had described unilateral rotary nystagmus, Hoyt and Keane 2 were irst to use the term “supe- rior oblique myokymia” as the electromyographic recordings displayed motor unit potential bursts. The pathophysiology is not clear but recent reports sup- port the neurovascular compression hypothesis. 3,4 However, most patients with SOM have no under- lying disease. Several medications have shown promise in treating SOM. This is the irst case report documenting symptomatic relief with Gabapentin in SOM due to vascular compression. CASE REPORT A 27-year-old right-handed male presented with an intermittent luttering sensation of his vision for 10 to 15 seconds per episode occurring 20 to 30 times a day for 3 months. Slitlamp examination showed intermittent torsional micro-tremor in the right eye. Tonic intorsion of the right eye became obvious on abduction. His examination was within normal limits otherwise. Conventional brain magnetic resonance imaging (MRI) showed no abnormality. To evaluate the brainstem and trochlear nerve MRI Fourier transform constructive interference in steady state sequence (CISS) was used. The proximal cister- nal segment of the trochlear nerve was seen to be compressed by the right superior cerebellar artery (SCA) while this was not seen on the contralateral side (Figure 1). The patient was started on oral carbamazepine 200 mg twice daily. On a subsequent visit, the dose was increased to 400 mg three times daily over a period of 2 weeks. The patient reported a noticeable improvement in his symptoms, and carbamazepine was discontinued due to elevation of transaminases 4 weeks later. After carbamazepine was discontin- ued, his symptoms began to interfere with his daily activities. Gabapentin was considered as it has the advantage of renal elimination. With slow titration so as to minimize sedation, gabapentin dose was increased to 600 mg three times daily over a period of 3 weeks, resulting in complete remission of SOM attacks. Thereafter, the patient was able to return to work. After 1 year gabapentin was tapered off. Over a follow-up period of 3 years there has been no recur- rence of SOM. DISCUSSION Superior oblique myokymia is a unique syndrome characterized by episodic monocular torsional and Neuro-ophthalmology, 33(6), 336–338, 2009 Copyright © 2009 Informa Healthcare USA, Inc. ISSN: 0165-8107 print/ 1744-506X online DOI: 10.3109/01658100903281724 CASE REPORT Gabapentin and Superior Oblique Myokymia Semai Bek, Tayfun Kasikci, Gencer Genc, and Zeki Odabasi Department of Neurology, Gulhane Medical Academy, Ankara, Turkey ABSTRACT Superior oblique myokymia (SOM) is an uncommon disorder characterized by episodic monocu- lar oscillopsia. Though the mechanism of SOM is not fully established, recent reports focus on the role of vascular compression. Several medications have been reported to be of beneit but a stan- dard protocol for SOM has not been established. This case report documents a complete symptom relief in SOM with a documented vascular compression using gabapentin. KEYWORDS: Gabapentin; superior oblique myokymia; trochlear nerve Received 23 May 2009; revised 08 July 2009; accepted 23 August 2009 Correspondence: Dr. Semai Bek, Gulhane Medical Faculty Department of Neurology, Etlik Ankara TURKEY 06018. E-mail: semaibek@yahoo.com.