Convergence Spasm: The Importance of Infrared Videotaping

A 49-year-old man presented to the Emergency Department with acute onset of painless diplopia that had manifested the day before. Upon a brief examination, bilateral weakness of abduction of the eyes was noted, and bilateral sixth nerve palsy was suspected. He was immediately investigated for central nervous system pathology. However, brain contrast-enhanced magnetic resonance imaging, computed tomography, and cerebrospinal fluid examination findings were all normal. On a careful examination using infrared videotaping, his pupils apparently constricted on abduction (Picture). Therefore, a diagnosis of convergence spasm (CS) was made. Reassuring the patient was sufficient to completely resolve the symptoms within a month. CS is characterized by an inappropriate appearance of the near triad, comprising convergence, miosis, and accommodation. The cause is mostly psychiatric; therefore, diagnosing CS properly is important (1). The observation of miosis during attempted abduction is the most reliable sign at bedside; however, in many cases, it is very difficult to make a diagnosis without infrared videotaping (2).