title: Mesopic pupil size in a refractive surgery population (13,959 eyes).
abstract: OBJECTIVE
  To evaluate factors that may affect mesopic pupil size in refractive surgery candidates.
  
  
  METHODS
  Medical records of 13,959 eyes of 13,959 refractive surgery candidates were reviewed, and one eye per subject was selected randomly for statistical analysis. Detailed ophthalmological examination data were obtained from medical records. Preoperative measurements included uncorrected distance visual acuity, corrected distance visual acuity, manifest and cycloplegic refraction, topography, slit lamp examination, and funduscopy. Mesopic pupil size measurements were performed with Colvard pupillometer. Relationship between mesopic pupil size and age, gender, refractive state, average keratometry, and pachymetry (thinnest point) were analyzed by means of ANOVA (+ANCOVA) and multivariate regression analyses.
  
  
  RESULTS
  Overall mesopic pupil size was 6.45 ± 0.82 mm, and mean age was 36.07 years. Mesopic pupil size was 5.96 ± 0.8 mm in hyperopic astigmatism, 6.36 ± 0.83 mm in high astigmatism, and 6.51 ± 0.8 mm in myopic astigmatism. The difference in mesopic pupil size between all refractive subgroups was statistically significant (p < 0.001). Age revealed the strongest correlation (r = -0.405, p < 0.001) with mesopic pupil size. Spherical equivalent showed a moderate correlation (r = -0.136), whereas keratometry (r = -0.064) and pachymetry (r = -0.057) had a weak correlation with mesopic pupil size. No statistically significant difference in mesopic pupil size was noted regarding gender and ocular side. The sum of all analyzed factors (age, refractive state, keratometry, and pachymetry) can only predict the expected pupil size in <20% (R = 0.179, p < 0.001).
  
  
  CONCLUSIONS
  Our analysis confirmed that age and refractive state are determinative factors on mesopic pupil size. Average keratometry and minimal pachymetry exhibited a statistically significant, but clinically insignificant, impact on mesopic pupil size.
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf, Martinis, Hamburg, Germany. slinke@uke.uni-hamburg.de
authors: Stephan J
authors: SJ
authors: Linke
authors: Julio
authors: J
authors: Baviera
authors: Gur
authors: G
authors: Munzer
authors: Otto H
authors: OH
authors: Fricke
authors: Gisbert
authors: G
authors: Richard
authors: Toam
authors: T
authors: Katz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000601:surgery*; D003315:Cornea / Q000601:surgery*; D005260:Female; D006801:Humans; D007498:Iris / Q000473:pathology*; D008297:Male; D055255:Mesopic Vision / Q000502:physiology*; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D011680:Pupil / Q000502:physiology*; D054140:Refractive Surgical Procedures; D014792:Visual Acuity; D055815:Young Adult