title: Pupil decentration and iris tilting detected by Orbscan: anatomic variations among healthy subjects and influence on outcomes of laser refractive surgeries.
abstract: OBJECTIVE
  To investigate the anatomic variations of entrance pupil decentration and tilting angle of the iris in healthy subjects and the influence of these factors on the outcome of laser in situ keratomileusis (LASIK).
  
  
  METHODS
  Minamiaoyama Eye Clinic, Tokyo, Japan.
  
  
  METHODS
  The degree of pupil decentration and tilting angle of the iris in 2280 eyes of 1144 myopic patients without abnormal findings by ophthalmologic examination were assessed using Orbscan. Of these, 901 eyes of 467 patients had LASIK. Multiple analysis of variance (ANOVA) was used to determine risk factors for reduction of postoperative best spectacle-corrected visual acuity (BSCVA) considering patient age, refractive power, tilting angle of the iris, pupil decentration, and corneal power.
  
  
  RESULTS
  The mean pupil decentration in all eyes was 0.19 mm +/- 0.11 (SD) (range 0 to 0.9 mm); tilting angle of the iris was 4.06 +/- 1.41 degrees (range 0.19 to 12.69 degrees). By multiple ANOVA, refractive power, pupil decentration, and tilting angle of the iris were significant for the reduction of BSCVA.
  
  
  CONCLUSIONS
  Some eyes with pupil decentration or tilting angle of the iris could not be detected under typical ophthalmologic examination but only with topographic examination. Attention should be paid to eyes with large pupil decentration and tilting angle of the iris because these may be risk factors for reduction of postoperative BSCVA during corneal refractive surgeries.
authors.affiliation: Department of Ophthalmology, Tokyo Dental College, Chiba, Japan. naokato@bc.iij4u.or.jp
authors.forename: Naoko
authors.initials: N
authors.lastname: Asano-Kato
authors.forename: Ikuko
authors.initials: I
authors.lastname: Toda
authors.forename: Chikako
authors.initials: C
authors.lastname: Sakai
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Hori-Komai
authors.forename: Yoji
authors.initials: Y
authors.lastname: Takano
authors.forename: Murat
authors.initials: M
authors.lastname: Dogru
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsubota
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003941:Diagnostic Techniques, Ophthalmological; D005139:Eyeglasses; D005260:Female; D006801:Humans; D007498:Iris / Q000473:pathology*; D020731:Keratomileusis, Laser In Situ; D008297:Male; D009216:Myopia / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D011680:Pupil; D012029:Refraction, Ocular; D012307:Risk Factors; D016896:Treatment Outcome; D014792:Visual Acuity