title: Anterior Corneal, Posterior Corneal, and Lenticular Contributions to Ocular Aberrations.
abstract: OBJECTIVE
  To determine the corneal surfaces and lens contributions to ocular aberrations.
  
  
  METHODS
  There were 61 healthy participants with ages ranging from 20 to 55 years and refractions -8.25 diopters (D) to +3.25 D. Anterior and posterior corneal topographies were obtained with an Oculus Pentacam, and ocular aberrations were obtained with an iTrace aberrometer. Raytracing through models of corneas provided total corneal and surface component aberrations for 5-mm-diameter pupils. Lenticular contributions were given as differences between ocular and corneal aberrations. Theoretical raytracing investigated influence of object distance on aberrations.
  
  
  RESULTS
  Apart from defocus, the highest aberration coefficients were horizontal astigmatism, horizontal coma, and spherical aberration. Most correlations between lenticular and ocular parameters were positive and significant, with compensation of total corneal aberrations by lenticular aberrations for 5/12 coefficients. Anterior corneal aberrations were approximately three times higher than posterior corneal aberrations and usually had opposite signs. Corneal topographic centers were displaced from aberrometer pupil centers by 0.32 ± 0.19 mm nasally and 0.02 ± 0.16 mm inferiorly; disregarding corneal decentration relative to pupil center was significant for oblique astigmatism, horizontal coma, and horizontal trefoil. An object at infinity, rather than at the image in the anterior cornea, gave incorrect aberration estimates of the posterior cornea.
  
  
  CONCLUSIONS
  Corneal and lenticular aberration magnitudes are similar, and aberrations of the anterior corneal surface are approximately three times those of the posterior surface. Corneal decentration relative to pupil center has significant effects on oblique astigmatism, horizontal coma, and horizontal trefoil. When estimating component aberrations, it is important to use correct object/image conjugates and heights at surfaces.
authors.affiliation: Institute of Health and Biomedical Innovation and School of Optometry and Vision Sciences, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: David A
authors.initials: DA
authors.lastname: Atchison
authors.affiliation: Institute of Health and Biomedical Innovation and School of Optometry and Vision Sciences, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Marwan
authors.initials: M
authors.lastname: Suheimat
authors.affiliation: Institute of Health and Biomedical Innovation and School of Optometry and Vision Sciences, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Ankit
authors.initials: A
authors.lastname: Mathur
authors.affiliation: Institute of Health and Biomedical Innovation and School of Optometry and Vision Sciences, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
authors.forename: Lucas J
authors.initials: LJ
authors.lastname: Lister
authors.affiliation: Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium 3Department of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium.
authors.forename: Jos
authors.initials: J
authors.lastname: Rozema
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000175:diagnosis / Q000503:physiopathology; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods*; D057108:Corneal Wavefront Aberration / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular; D055815:Young Adult