title: Effect of Pupil Size on Flicker ERGs Recorded With RETeval System: New Mydriasis-Free Full-Field ERG System.
abstract: OBJECTIVE
  We studied whether pupil size affects the flicker electroretinograms (ERGs) recorded by RETeval, a new mydriasis-free full-field flicker ERG system.
  
  
  METHODS
  We studied 10 healthy subjects. The RETeval manufacturer claims that the system delivers a constant flash retinal illuminance by adjusting the flash luminance to compensate for changes in the pupil size. Two experiments were performed. First, the flicker ERG was recorded every 3 minutes after the instillation of mydriatics. Second, the flicker ERG was recorded while the subjects wore soft contact lenses with two different artificial pupil sizes.
  
  
  RESULTS
  The first experiment showed that as pupil size increased, the amplitudes of the fundamental component of the flicker ERG did not change significantly, but the implicit times of the fundamental component were significantly prolonged for larger pupil sizes. There was a significant positive correlation between the pupillary area and implicit time of the fundamental component (r = 0.93, P < 0.001). The second experiment showed that the implicit times of the fundamental component in the flicker ERG were significantly longer with larger artificial pupil.
  
  
  CONCLUSIONS
  The results suggest that the effective retinal illuminance of the stimulus delivered by the RETeval system decreases for large pupil sizes. However, in most clinical testing situations, patients' undilated pupils will likely be sufficiently small to fall within the range for which the system delivers a stimulus of constant retinal illuminance.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Kato
authors.forename: Mineo
authors.initials: M
authors.lastname: Kondo
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Kengo
authors.initials: K
authors.lastname: Ikesugi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Matsubara
mesh_terms: D000328:Adult; D004596:Electroretinography / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009184:Mydriatics / Q000494:pharmacology; D011680:Pupil / Q000187:drug effects
chemical_list: D009184:Mydriatics