title: Fourier series harmonic analysis of corneal topography following suture removal after penetrating keratoplasty.
abstract: OBJECTIVE
  To evaluate quantitatively the influence of suture removal after penetrating keratoplasty on corneal refraction including irregular astigmatism.
  
  
  METHODS
  Subjects were 42 eyes of 39 patients with clear corneal grafts who underwent suture removal after penetrating keratoplasty. Videokeratography data taken before and after suture removal were decomposed using Fourier harmonic analysis into spherical power, regular astigmatism, and irregular astigmatism (asymmetry and higher order irregularity).
  
  
  RESULTS
  On average, spherical power significantly increased after suture removal (p < 0.0001, paired t test), and regular astigmatism did not change significantly (p = 0.247). Suture removal significantly decreased asymmetry (p < 0.0001) and higher order irregularity (p < 0.0001).
  
  
  CONCLUSIONS
  Suture removal after penetrating keratoplasty induces myopic shift and reduction in irregular astigmatism of the cornea.
authors.affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.
authors.forename: Fumie
authors.initials: F
authors.lastname: Kagaya
authors.forename: Atsuo
authors.initials: A
authors.lastname: Tomidokoro
authors.forename: Sumiyoshi
authors.initials: S
authors.lastname: Tanaka
authors.forename: Shiro
authors.initials: S
authors.lastname: Amano
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oshika
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001251:Astigmatism / Q000209:etiology* / Q000503:physiopathology; D003315:Cornea / Q000473:pathology* / Q000503:physiopathology; D019781:Corneal Topography; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D013536:Suture Techniques / Q000009:adverse effects*