The effect of phenylephrine on Müller muscle. A blepharogram study of eyelid motion.

PURPOSE

The blepharogram technique is used to study the effect of a drug on blinking. The authors show that ocular instillation of phenylephrine, a stimulant of Müller muscle of the eyelid, accelerates the up phase of the blink.

METHODS

Motion of a tiny search coil glued to the eyelid moving in a weak magnetic field modifies an induced alternating current which is amplified and used to display the position of the upper eyelid in degrees on the ordinate of a graph with time in milliseconds on the abscissa. The graph is called a blepharogram. Blepharogram studies and individual blink analysis show the effect of phenylephrine on eyelid motion (blinking).

RESULTS

Instillation of phenylephrine accelerated the up phase of the blink in all ten experimental subjects. In 65% of subjects, phenylephrine also produced or increased newly described N and M blepharogram patterns.

CONCLUSION

This is the first instrumental detection of the effect of a pharmacologic agent on eyelid motion. The blepharogram technique provides insight into eyelid physiology and can be used to study any neuromuscular condition that affects eyelid motion.