title: Repeated pupil size measurements in refractive surgery candidates.
abstract: OBJECTIVE
  To evaluate the individual variation in pupil diameter measurements in refractive surgery candidates under standardized conditions over 2 testing sessions using a digital infrared pupillometer.
  
  
  METHODS
  Department of Ophthalmology, University Medical Center Regensburg, Regensburg, Germany.
  
  
  METHODS
  The pupil size in both eyes of consecutive refractive surgery candidates was measured under 2 illumination levels (scotopic at 0.03 lux, low mesopic at 0.82 lux) with a digital infrared pupillometer (Procyon P2000 SA). Before measurement, a standardized dark-adaptation protocol was used. Measurements were taken twice on separate occasions.
  
  
  RESULTS
  The study evaluated 318 eyes of 159 patients with a mean age of 36.3 years +/- 10.2 (SD). The mean interval between measurements was 53 +/- 62.8 days. Despite sufficient power (beta < 0.05), there was no statistically significant difference between 2 consecutive measurements under scotopic and low mesopic illumination.
  
  
  CONCLUSIONS
  Using a standardized dark-adaptation protocol, refractive surgery candidates showed no significant variation in scotopic or low mesopic pupil diameter over 2 testing sessions.
authors.affiliation: Department of Ophthalmology, University Medical Centers, Regensburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Robl
authors.forename: Ieva
authors.initials: I
authors.lastname: Sliesoraityte
authors.forename: Jost
authors.initials: J
authors.lastname: Hillenkamp
authors.forename: Philipp
authors.initials: P
authors.lastname: Prahs
authors.forename: Chris P
authors.initials: CP
authors.lastname: Lohmann
authors.forename: Horst
authors.initials: H
authors.lastname: Helbig
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Herrmann
mesh_terms: D000293:Adolescent; D000328:Adult; D003623:Dark Adaptation; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007498:Iris / Q000033:anatomy & histology*; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011680:Pupil / Q000502:physiology*; D054140:Refractive Surgical Procedures; D055815:Young Adult