title: Effect of pupil size on corneal aberrations before and after standard laser in situ keratomileusis, custom laser in situ keratomileusis, and corneal refractive therapy.
abstract: OBJECTIVE
  To evaluate the effect of changing the pupil size on the corneal first-surface higher-order aberrations induced by different refractive treatments: standard laser in situ keratomileusis (LASIK), custom LASIK, and corneal refractive therapy.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Eighty-one right eyes from patients with a mean age of 29.94 +/- 7.5 years, of which 50 were female (61.7%), were analyzed retrospectively at the Clínica Oftalmológica NovoVision, Madrid, Spain. Corneal videokeratographic data were used to obtain corneal first-surface higher-order aberrations for aperture diameters from 3 to 8 mm using the Vol-CT software (Sarver & Associates, Inc). Total root mean square (RMS) and RMS for third- to sixth-order Zernike polynomials as well as spherical-like, coma-like, secondary astigmatism, and spherical plus coma-like variables were calculated.
  
  
  RESULTS
  We verified an increase in the higher-order aberration total RMS after treatments of 0.014 +/- 0.025 microm, 0.019 +/- 0.027 microm, and 0.018 +/- 0.031 microm for standard LASIK, custom LASIK, and corneal refractive therapy, respectively, for 3-mm pupil diameter. For the 8-mm aperture diameter, changes in total RMS increased by a factor of 50 compared with the variation for the 3-mm diameter up to 0.744 +/- 0.731 microm, 0.493 +/- 0.794 microm, and 0.973 +/- 1.055 microm for standard LASIK, custom LASIK, and corneal refractive therapy, respectively.
  
  
  CONCLUSIONS
  The 3 techniques increase the wavefront aberrations of the cornea and change the relative contribution of coma-like and spherical-like aberrations. For a large aperture (> 5 mm), corneal refractive therapy induces more spherical-like aberrations than standard and custom LASIK. However, no clinically or statistically significant differences existed for narrower apertures. Standard and custom LASIK did not display statistically significant differences regarding higher-order aberrations.
authors.affiliation: Department of Physics, University of Minho, Braga, Portugal. aqp@fisica.uminho.pt <aqp@fisica.uminho.pt>
authors.forename: António
authors.initials: A
authors.lastname: Queirós
authors.forename: César
authors.initials: C
authors.lastname: Villa-Collar
authors.forename: José Manuel
authors.initials: JM
authors.lastname: González-Méijome
authors.forename: Jorge
authors.initials: J
authors.lastname: Jorge
authors.forename: Angel Ramón
authors.initials: AR
authors.lastname: Gutiérrez
mesh_terms: D000293:Adolescent; D000328:Adult; D003261:Contact Lenses; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000503:physiopathology*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000628:therapy*; D011680:Pupil / Q000502:physiology*; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology