title: Effect of pupil dilation on the accuracy of the IOLMaster.
abstract: OBJECTIVE
  To evaluate the effect of pupil dilation on the accuracy of the IOLMaster (Zeiss) in performing biometry and to assess test-retest variability without pupil dilation.
  
  
  METHODS
  Ophthalmic outpatient department of a district general hospital.
  
  
  METHODS
  This prospective study comprised consecutive patients presenting to a cataract clinic (study group) who had biometry performed with the IOLMaster before and after pupil dilation. A control group was recruited from consecutive patients attending a cataract preassessment clinic who had 2 sets of biometric measurements with the IOLMaster but without pupil dilation. The SRK/T formula was used to calculate intraocular lens (IOL) power.
  
  
  RESULTS
  The IOLMaster showed excellent reproducibility in the control group with no significant test-retest variability between the 2 sets of readings. The study group showed a statistically significant change in K2 and average keratometry values (P <.05) but no significant change in axial length or IOL power between undilated and dilated pupil biometry readings. No systematic errors were revealed.
  
  
  CONCLUSIONS
  Dilating the pupil did not adversely affect the clinical accuracy of the IOLMaster.
authors.affiliation: Department of Ophthalmology, Queen Mary's Hospital, Kent, England, United Kingdom.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Heatley
authors.forename: Laurence A
authors.initials: LA
authors.lastname: Whitefield
authors.forename: Charles E
authors.initials: CE
authors.lastname: Hugkulstone
mesh_terms: D000818:Animals; D001699:Biometry / Q000295:instrumentation*; D035061:Control Groups; D006801:Humans; D007368:Interferometry / Q000379:methods*; D007910:Lenses, Intraocular; D055095:Optics and Photonics / Q000295:instrumentation*; D012025:Reflex, Pupillary; D015203:Reproducibility of Results