Diagnostic ophthalmic ultrasound study of brimonidine tartrate 0.2% and apraclonidine 0.5% effect on iris configuration

Purpose: To analyze, using a diagnostic ophthalmic ultrasound (DOU) (I3 system ABD v2 Diagnosis Ophthalmic Ultrasound, Software Version 5x, Innovative Imaging Inc), possible effects of brimonidine tartrate 0.2% and apraclonidine 0.5% on iris configuration. Methods: Ten subjects (20 and 40 years of age) consented to participate. The peripheral iris, iris root thickness, iris/lens distance and anterior chamber depth were measured by DOU. Baseline and serial measurements at three luminance levels (>6.4 cd/m², <0.82-0.4 cd/m² and <0.2-0.02 cd/m²) were obtained periodically during 4 hours. Either one drop of brimonidine tartrate 0.2% or apraclonidine 0.5% in one eye vs. a placebo in the contra-lateral eye were instilled following baseline measurements. The observations for each drug were carried out on different days. A model to test for nested random effects, controlling for subject's age, race and sex, was used for statistical analysis. Results: No significant changes in the intraocular anterior segment configuration zones analyzed was observed for brimonidine tartrate 0.2% or apraclonidine 0.5%. Conclusion: Neither brimonidine tartrate 0.2% nor apraclonidine 0.5% appears to have a significant effect on the analyzed iris configuration zones.