title: Effect of pupil size on uncorrected visual acuity in astigmatic eyes.
abstract: OBJECTIVE
  To determine the effects of pupil size on uncorrected visual acuity (UCVA) in astigmatic eyes.
  
  
  METHODS
  The authors examined 20 normal eyes of 20 healthy volunteers (age 26.7±4.9 years (mean±SD); 8 men, 12 women). After fully correcting cycloplegic refraction, the authors created with-the-rule and against-the-rule astigmatism of 1, 2, and 3 dioptres (D) in each eye, and then assessed UCVA using artificial pupils (1 to 5 mm) in these astigmatic eyes. Measurements were performed three times, and the mean value was used for statistical analysis.
  
  
  RESULTS
  In eyes with with-the-rule astigmatism of 1, 2 and 3 D, logMAR UCVA was 0.04±0.08, 0.09±0.09 and 0.16±0.16 for 1 mm pupils, -0.01±0.09, 0.12±0.15 and 0.33±0.24 for 2 mm pupils, 0.02±0.09, 0.20±0.19 and 0.46±0.30 for 3 mm pupils, 0.02±0.08, 0.24±0.20 and 0.48±0.21 for 4 mm pupils, and 0.08±0.10, 0.33±0.18 and 0.53±0.22 for 5 mm pupils, respectively. The variance of the data was statistically significant (p=0.03 for 1 D, p<0.001 for 2 D, p<0.001 for 3 D, analysis of variance). Similar results were obtained in eyes with against-the-rule astigmatism.
  
  
  CONCLUSIONS
  Both the amount of astigmatism and the pupil size can affect UCVA in astigmatic eyes. It is suggested that not only the amount of astigmatism but also the pupil size should be taken into consideration for acquiring better visual performance in astigmatic eyes.
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan. kamiyak-tky@umin.ac.jp
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kamiya
authors.forename: Hidenaga
authors.initials: H
authors.lastname: Kobashi
authors.forename: Kimiya
authors.initials: K
authors.lastname: Shimizu
authors.forename: Takushi
authors.initials: T
authors.lastname: Kawamorita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uozato
mesh_terms: D057128:Aberrometry; D000328:Adult; D001251:Astigmatism / Q000503:physiopathology*; D019781:Corneal Topography; D003519:Cyclopentolate / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D009184:Mydriatics / Q000008:administration & dosage; D011446:Prospective Studies; D011680:Pupil / Q000187:drug effects / Q000502:physiology*; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult
chemical_list: D009184:Mydriatics; D003519:Cyclopentolate