title: The comparison of mydriatic effect between two drugs of different mechanism.
abstract: OBJECTIVE
  To maximize effective use of mydriatic drugs through comparing the pupillary dilation effects between 1% tropicamide and 2.5% phenylephrine.
  
  
  METHODS
  Fifty people requiring pupillary dilation were divided into 3 groups. Group 1 was treated with one drop of 1% tropicamide in the right eye and one drop of 2.5% phenylephrine in the left eye. Group 2 was treated twice during a 5-minute interval with 1% tropicamide in the right eye. Group 3 was treated twice during a 5-minute interval with 2.5% phenylephrine in the right eye. Groups 2 and 3 were treated with 2.5% phenylephrine and 1% tropicamide in the left eye, administered during a 5-minute interval. The pupillary size was measured in all groups for 40 minutes following eye drops administration.
  
  
  RESULTS
  The mean patient age was 15.7 years. Group 1 included 10 patients, and groups 2 and 3 included 20 patients each. Eight patients in group 1 and 16 patients in group 2 developed a larger right pupil. Fourteen patients in group 3 developed a larger left pupil.
  
  
  CONCLUSIONS
  Our study showed that 1% tropicamide, with its parasympathetic antagonistic mechanism of action, was more effective at inducing pupillary dilation than 2.5% phenylephrine, and the combination of 1% tropicamide and 2.5% phenylephrine was more effective than multiple drops of single eye drops.
authors.affiliation: Department of Ophthalmology, College of Medicine, Keimyung University of Korea, Daegu, Korea.
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Young-Chun
authors.initials: YC
authors.lastname: Lee
authors.forename: Se-Youp
authors.initials: SY
authors.lastname: Lee