Aging and topical pilocarpine concentrations effects on pupil size and tear flow rate

Abstract

Purpose This is to evaluate the effects of age and different concentrations of pilocarpine on tear flow rate and pupil size. Methods The tear flow rates and pupil sizes of eighty-one volunteers were measured with Schimer's strips and a meter rule gauge, respectively. These procedures were also employed in testing the effects of 2 % and 4 % concentrations of pilocarpine on tear secretion and pupil constriction. Results There were significant differences between the initial mean tear flow rate and the mean tear flow rates after the installation of 2 % pilocarpine (critical t = 1.96 and calculated t = 6.46) and 4 % pilocarpine (calculated t = 8.83). There were no significant differences in the initial tear flow rates between the sexes. There were significant differences between the mean tear flow rates obtained with 2 % and 4 % concentrations of pilocarpine (calculated t = 3.41). The mean initial tear flow rate for the eighty-one volunteers was 13.84 mm ± 1.19 (SD).There were significant differences between the mean initial pupil size 2.96 mm ± 1.04 (SD) and the mean pupil sizes 2.38 mm ± 1.11(SD) after the instillation of 2 % pilocarpine (Critical t = 1.96 and calculated t = 2.46). Conclusion The basal tear flow rate decreased with advancing age and topical pilocarpine increased tears secretion in all the age groups. The age groups (31 years and above) were more tolerant to the stinging effect of pilocarpine and induced reduced pupil sizes, but there were no significant differences between the mean pupil sizes obtained with the pilocarpine concentrations.