Purpose: To evaluate the effect of 3 types of topically applied miotic eyedrops on the pupil diameter in normal eyes.
Setting: Department of Neurosciences, Section of Ophthalmology, University of Pisa, Pisa, Italy.
Methods: This prospective study comprised 60 eyes of 30 healthy volunteers treated with aceclidine 0.02%, brimonidine tartrate 0.20%, and dapiprazole 0.25%. Pupil diameter was measured under scotopic, mesopic (4 lux), and photopic (50 lux) conditions using an infrared pupillometer incorporated into a CSO topographer. The first measurement was obtained before single instillation of 1 type of miotic eyedrop. Subsequent measurements were taken after 30, 120, and 240 minutes. Each additional medication was tested after an interval of at least 6 weeks to avoid possible effects from the previously administered drug. All patients received a questionnaire and were asked to grade the tolerability of each eyedrop using a subjective scoring system.
Results: Aceclidine 0.02% had no significant miotic effect. Brimonidine tartrate 0.20% caused significant miosis within 30 minutes and 120 minutes; after 240 minutes, the effect under all luminance conditions decreased to baseline levels without reaching the initial level. Dapiprazole 0.25% had a miotic effect similar to that of brimonidine but produced many side effects including hyperemia and burning, which many patients said caused significant discomfort.
Conclusions: Brimonidine tartrate 0.20% had the best miotic effect of the 3 agents tested and was well tolerated by the patients. The reproducible miotic effect of brimonidine tartrate under all lighting conditions might benefit postoperative refractive patients who report night-vision difficulties related to large pupils.