Benzodiazepines impair smooth pursuit eye movements.

Five healthy male volunteers received single oral doses of 10 mg diazepam, 20 mg temazepam and placebo, in a double-blind, randomised fashion. Smooth pursuit eye movement velocity and serum benzodiazepine concentration were measured before and after at 0.5,1,1.5,2,3,4,6,9 and 12 h after administration of the treatments. Significant decrease in smooth pursuit eye movement velocity as compared to placebo was observed between 0.5-2 h after temazepam, and between 1-2 h after diazepam. Smooth pursuit eye movement velocity was log-linearly correlated with serum temazepam and diazepam concentration. The results demonstrate the relationship between serum benzodiazepine concentration and its effect on an objective measure of oculomotor performance.