title: Pupillometry study of brimonidine tartrate 0.2% and apraclonidine 0.5%.
abstract: This study investigated possible effects of brimonidine tartrate 0.2% and apraclonidine 0.5% on pupil diameter. Ten subjects between 20 and 40 years of age participated. A Colvard pupillometer (Oasis Medical) was used to measure pupil diameter. Baseline and serial measurements were obtained at 3 luminance levels (>6.4, <0.82-0.4, and <0.2-0.02 cd/m(2)) during a 4-hour interval following instillation of 1 drop of brimonidine tartrate 0.2% or apraclonidine 0.5% in one eye versus a placebo in the contralateral eye. The measurements for each drug were obtained on different days. A nested random effects model controlling for subject's age, race, and sex was used for statistical analysis. A maximum reduction in pupil diameter was observed at 90 minutes from instillation (1.40 mm at >6.4 cd/m(2), 1.69 mm at <0.82-0.4 cd/m(2), and 1.55 mm at <0.2-0.02 cd/m(2)) for brimonidine tartrate 0.2%. At all time intervals and illumination levels, miosis (P < .01) occurred. Apraclonidine 0.5% did not produce a significant effect on pupil diameter. Brimonidine tartrate 0.2% produced a moderate miotic effect. No effect was observed for apraclonidine 0.5%. A predominant agonistic effect on α-2 receptors of the iris dilator may explain this behavior.
authors.affiliation: Nova Southeastern University College of Optometry, Ft Lauderdale, FL 33328, USA. ebesada@nova.edu
authors.forename: Eulogio
authors.initials: E
authors.lastname: Besada
authors.forename: Kimberly
authors.initials: K
authors.lastname: Reed
authors.forename: Perla
authors.initials: P
authors.lastname: Najman
authors.forename: Diana
authors.initials: D
authors.lastname: Shechtman
authors.forename: Patrick
authors.initials: P
authors.lastname: Hardigan
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000494:pharmacology*; D000328:Adult; D000068438:Brimonidine Tartrate; D003000:Clonidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008916:Miotics; D010783:Photometry; D011680:Pupil / Q000187:drug effects*; D011810:Quinoxalines / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D008916:Miotics; D011810:Quinoxalines; D000068438:Brimonidine Tartrate; C016986:apraclonidine; D003000:Clonidine