The Effect of Topical Pilocarpine on Basic Tear Secretion

ABSTRACT

PURPOSE: To evaluate the effect of topical pilocarpine on basic tear secretion, using the Schirmer test. METHODS: The Schirmer test was performed in 22 eyes of 11 healthy volunteers before instillation and at 10, 20, and 30 minutes after instillation of 1% pilocarpine and in 22 eyes of 12 healthy volunteers before instillation and at 10, 20, and 30 minutes after instillation of 2% pilocarpine. As for control group, the Schirmer test was performed in 22 eyes of 11 healthy volunteers by the same method except with normal saline. RESULTS: The ratio of tear secretion was calculated by dividing the wet length of a Schirmer strip after instillation by the wet length before instillation for comparative analysis. In the control group, the mean ratio decreased with time to 0.78 at 10 minutes, 0.64 at 20 minutes, and 0.63 at 30 minutes after instillation of normal saline. In the 1% pilocarpine group, the mean ratio decreased with time, but there was no significant difference in comparison to the ratio of the control group. In the 2% pilocarpine group, the ratio increased significantly to 1.28 (p<0.001) at 10 minutes, 1.07 (p=0.002) at 20 minutes, and decreased to 0.63 (p=0.041) at 30 minutes after instillation. CONCLUSIONS: The basic tear secretion did not change significantly after instillation of 1% pilocarpine but increased significantly at 10 minutes after instillation of 2% pilocarpine to the highest level observed, which was followed by a decrease in basic tear secretion.