title: Influence of pupillary diameter, ciliary muscle tone, and ambient light on nerve fiber layer measurements with scanning laser polarimetry.
abstract: OBJECTIVE
  To evaluate the influence of the pupillary diameter, ciliary muscle tone, and room light on nerve fiber layer measurements with the scanning laser polarimeter (GDx).
  
  
  METHODS
  One randomly selected eye of ten normal volunteers was examined with the GDx in a two-day protocol under eight testing conditions (pilocarpine 1%, phenylephrine 10%, tropicamide 1%, or no drops with room lights on or off). The twelve parameters, obtained by the GDx, were compared under the eight testing conditions, using two way ANOVA for repeated measurements and Tukey HSD post hoc test.
  
  
  RESULTS
  Ten of the twelve parameters were statistically significantly different (P < 0.05) when measured under the three medication or no medication conditions, controlling for the ambient light status. There were no significant differences when measured with the light on or off, controlling for use of drops.
  
  
  CONCLUSIONS
  Nerve fiber layer measurements with the GDx were influenced by drugs affecting pupillary diameter, but not by the status of room light or ciliary muscle tone.
authors.affiliation: Ophthalmology Department, Federal University of São Paulo, São Paulo, Brazil 04023-062. augusto.paranhos@uol.com.br
authors.forename: Augusto
authors.initials: A
authors.lastname: Paranhos
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Silvestre
authors.forename: Carlo C
authors.initials: CC
authors.lastname: Passerotti
authors.forename: Elizabeth M R
authors.initials: EM
authors.lastname: Martins
authors.forename: Paulo Augusto
authors.initials: PA
authors.lastname: de Arruda Mello
authors.forename: João Antônio
authors.initials: JA
authors.lastname: Prata
authors.forename: Milton Bruce
authors.initials: MB
authors.lastname: Shields
mesh_terms: D000328:Adult; D002924:Ciliary Body / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D005260:Female; D006801:Humans; D007834:Lasers; D008027:Light; D008297:Male; D008916:Miotics / Q000008:administration & dosage; D009130:Muscle, Smooth / Q000502:physiology*; D009184:Mydriatics / Q000008:administration & dosage; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D019721:Ophthalmoscopes; D009887:Ophthalmoscopy / Q000379:methods*; D009900:Optic Nerve / Q000502:physiology*; D010656:Phenylephrine / Q000008:administration & dosage; D010862:Pilocarpine / Q000008:administration & dosage; D011680:Pupil / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D012165:Retinal Ganglion Cells / Q000502:physiology; D014331:Tropicamide / Q000008:administration & dosage
chemical_list: D008916:Miotics; D009184:Mydriatics; D010862:Pilocarpine; D010656:Phenylephrine; D014331:Tropicamide