Long-lasting organic spasm of the near reflex.

A 57-year-old man was examined after head trauma and found to have long-lasting organic spasm of the near reflex lacking accommodative spasm. Convergence and miosis had been consistently observed for the follow-up period of one year and three months. Electrooculographical findings showed that there was no lateral rectus muscle palsy in either eye, and that his esotropia became intense in total darkness, compared with fixation on a visual target. Persistent convergence and miosis completely disappeared within 7 minutes after intravenous injections of benzodiazepine. Furthermore, he was able to make a normal near reflex when the spasm disappeared. The effect of benzodiazepine suggests that the disturbance of the GABAergic (gamma-aminobutyric acid) inhibitory system in the near reflex may be responsible for the occurrence of the spasm.