Purpose:
to evaluate the effect of brimonidine tartarate 0,15% on pupillary diameter in eight hours.
Methods:
nine normal volunteers underwent a five binocular pupillary measurement protocol. The first measure was with no drug. Their eyes were then randomized so one eye had brimonidine and the other had no drop. Measurement of the pupil diameter was performed using a simultaneous binocular infrared pupillometer. Each photo was taken ten times each 0,5 seconds with two hours interval. The mean of each ten sections was used for analysis. Statistical analysis was performed with the ANOVA test, repeated measures considered. To evaluate the effect on the non–treated eye, a student t–test for dependent variables was performed between the pre measures and the mean of the 2,4 and 6 hours measures.
Results:
There was a tendency of pupil miotic effect on treated eye compared with the control eye (P=0,738) but there was a significant effect on non–treated eye for a mean difference of almost one millimeter, mean pre measures: 4,9 mm±0,99 and mean of the first 3 periods: 4,01 mm±0,94. The miotic effect was also seen when both eyes were analyzed together compared with the pre–treatment measurements (P=0,02). Table 1. Mean and standard deviation of the pupil diameter of the two groups in all intervals.
ANOVA P=0,738
Conclusions:
there is a miotic effect of brimonidine for at least 6 hours after drug instillation and this miotic response could affect the control eyes.
Keywords: pupillary reflex • pharmacology