title: The effect of pupil dilation on biometric parameters of the Lenstar 900.
abstract: OBJECTIVE
  To evaluate the effect of pupil dilation on the biometric parameters of the Lenstar LS 900 (Haag Streit AG, Koeniz, Switzerland).
  
  
  METHODS
  In this cross-sectional study of 33 eyes with cataracts, axial length (AL), anterior chamber depth, intraocular lens (IOL) power, keratometry, and pupil diameter measurements were performed using Lenstar biometry before and after pupil dilatation. Intraobserver repeatability was assessed by taking 2 consecutive recordings of biometric parameters using Lenstar biometry in the undilated pupils of 30 eyes with cataracts.
  
  
  RESULTS
  The mean difference in AL measurements from intraobserver readings was -0.001 ± 0.01 mm. The study group showed a statistically significant change in the first keratometry reading and anterior chamber depth values (P < 0.05); however, the mean difference in AL and IOL power was statistically insignificant between the undilated and dilated pupil Lenstar biometry readings. Three cases in the study group (9.1%) and 1 case in the control group (3.3%) demonstrated changes in IOL power >0.50 diopter.
  
  
  CONCLUSIONS
  Dilated and undilated pupil size did not affect the measurement of IOL using the Lenstar biometry.
authors.affiliation: Department of Ophthalmology, Selcuklu Faculty of Medicine, Selcuk University, Konya, Turkey. drberkerbakbak@yahoo.com
authors.forename: Berker
authors.initials: B
authors.lastname: Bakbak
authors.forename: Bengu E
authors.initials: BE
authors.lastname: Koktekir
authors.forename: Sansal
authors.initials: S
authors.lastname: Gedik
authors.forename: Huseyin
authors.initials: H
authors.lastname: Guzel
mesh_terms: D000328:Adult; D000368:Aged; D000867:Anterior Chamber / Q000503:physiopathology; D058452:Axial Length, Eye / Q000503:physiopathology; D001699:Biometry / Q000295:instrumentation; D002386:Cataract / Q000175:diagnosis / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009907:Optometry / Q000295:instrumentation*; D011680:Pupil / Q000502:physiology*; D015203:Reproducibility of Results