title: Effect of pupil size on uncorrected visual acuity in pseudophakic eyes with astigmatism.
abstract: OBJECTIVE
  To study the effect of pupil size on the relationship between refractive astigmatism and uncorrected distance visual acuity (UDVA) and pseudoaccommodation in pseudophakic eyes.
  
  
  METHODS
  Thirty-six eyes from 36 patients who underwent phacoemulsification and intraocular lens (IOL) implantation were included. All eyes were divided into two groups based on the presence of postoperative-with-the-rule astigmatism or against-the-rule astigmatism. Uncorrected and corrected distance visual acuity (CDVA), refractive astigmatism, subjective accommodation amplitude, and pupil sizes under photopic and mesopic conditions were measured 1 month postoperatively. The effects of pupil size on the relationship between refractive astigmatism and UDVA were investigated.
  
  
  RESULTS
  Against-the-rule astigmatism had a moderate but significant negative linear correlation with UDVA irrespective of the pupil size (R(2)=0.60, P<.01). A moderate but significant negative linear correlation was found when the pupil diameter exceeded 2.9 mm in eyes with with-the-rule astigmatism (R(2)=0.46, P=.04). Refractive astigmatism was not significantly correlated with pseudoaccommodation regardless of the pupil diameter in either group.
  
  
  CONCLUSIONS
  The results of the current study suggest that pupil size may have an impact on postoperative UDVA in eyes having against-the-rule astigmatism and in eyes with a large pupil diameter and with-the-rule astigmatism.
authors.affiliation: Department of Opthalmology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Kazuno
authors.initials: K
authors.lastname: Negishi
authors.forename: Murat
authors.initials: M
authors.lastname: Dogru
authors.forename: Takefumi
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Torii
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tsubota
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000503:physiopathology*; D006801:Humans; D019654:Lens Implantation, Intraocular; D008875:Middle Aged; D018918:Phacoemulsification; D019591:Pseudophakia / Q000503:physiopathology*; D011680:Pupil / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*