title: Effect of brimonidine tartrate ophthalmic solution 0.2% on pupil size in normal eyes under different luminance conditions.
abstract: OBJECTIVE
  To evaluate the effect of brimonidine tartrate ophthalmic solution 0.2% (Alphagan) on pupil size in normal eyes. Three luminance conditions were used to assess the potential use of brimonidine in postoperative refractive patients who experience nighttime vision problems related to large pupil size.
  
  
  METHODS
  McDonald Eye Associates, Fayetteville, Arkansas, USA.
  
  
  METHODS
  Pupil size was measured in 16 eyes of 16 participants with the Colvard pupillometer under 3 luminance conditions. One drop of brimonidine 0.2% was administered to each patient. Pupil size was then measured using the same technique 30 minutes and 4 and 6 hours after drop administration.
  
  
  RESULTS
  Under scotopic conditions, 100% of the pupils showed significant miosis at 30 minutes (P <.05). The effect continued in all eyes for 4 hours. At 6 hours, a miotic effect was still present in 81.3%. However, under photopic luminance, there was no significant effect on pupil size in all 16 eyes (P >.05). The pupil size in 5 eyes (31.2%) was not affected at 30 minutes or 4 or 6 hours. At 6 hours, 15 eyes (93.8%) had returned to their preinstillation size.
  
  
  CONCLUSIONS
  Brimonidine tartrate 0.2% had a significant effect in decreasing pupil size under scotopic conditions. The results indicate that the drug can decrease night-vision difficulties such as halos, star bursts, glare, and monocular diplopia in postoperative refractive patients.
authors: McDonald Eye Associates, Fayetteville, Arkansas, USA. mcdonaldje@mcdonaldeye.com
authors: J E
authors: JE
authors: McDonald
authors: A M
authors: AM
authors: El-Moatassem Kotb
authors: B B
authors: BB
authors: Decker
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000328:Adult; D000068438:Brimonidine Tartrate; D005260:Female; D006801:Humans; D008029:Lighting; D008297:Male; D008875:Middle Aged; D015877:Miosis / Q000139:chemically induced; D009883:Ophthalmic Solutions; D011680:Pupil / Q000187:drug effects*; D011810:Quinoxalines / Q000008:administration & dosage*; D012025:Reflex, Pupillary; D014786:Vision Disorders / Q000517:prevention & control
chemical_list: D000316:Adrenergic alpha-Agonists; D009883:Ophthalmic Solutions; D011810:Quinoxalines; D000068438:Brimonidine Tartrate