Eyelid movements before and after botulinum therapy in patients with lid spasm.

Quantitative analysis of lid motility is presented for 4 individuals with hemifacial spasm and 1 with Meige's syndrome. The data were obtained, by means of a magnetic search coil technique, prior to and 1 week after injection of botulinum toxin into the orbicularis oculi muscle. Before treatment, the peak velocity of blink-related lid lowering and lid raising was slower than normal, yet lid saccades were normal. After botulinum treatment, significant decreases occurred in (1) the amplitude of blinks and lid saccades, and (2) the peak velocity of the blink down-phase. Botulinum treatment significantly alters blink lid-lowering kinematics, while saccadic lid-lowering kinematics are normal, providing further evidence that the orbicularis oculi muscle does not play a primary role in downward lid saccades.