title: Long-term corneal wavefront aberration variations after photorefractive keratectomy for myopia and myopic astigmatism.
abstract: OBJECTIVE
  To analyze the higher-order corneal wavefront aberration during an 8-year follow-up after photorefractive keratectomy (PRK).
  
  
  METHODS
  IRCCS Fondazione G.B. Bietti, Rome, Italy.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Patients having PRK using the Technolas 217C excimer laser platform were divided into 3 groups according to the preoperative refraction as follows: low myopia, high myopia, and astigmatism. The preoperative and 1-, 4-, 6-, and 8-year postoperative root mean square (RMS) values of coma, spherical aberration, and total higher-order aberrations (HOAs) were calculated with 3.5 mm and 6.0 mm simulated pupils. The mean preoperative and postoperative higher-order corneal wavefront aberration maps, point-spread functions, and radial modulation transfer functions (MTFs) were represented to describe the impact of PRK on the optical quality of the anterior cornea.
  
  
  RESULTS
  The study enrolled 33 patients (66 eyes). Corneal spherical aberration was statistically significantly higher after PRK for simple myopia with 3.5 mm and 6.0 mm pupils (P<.05). The postoperative increase in coma was statistically significant in the high-myopia group with both pupil sizes (P<.05). Total RMS HOAs increased postoperatively with a 6.0 mm pupil in all groups (P<.05). The mean radial MTF was almost stable in all groups between preoperatively and postoperatively.
  
  
  CONCLUSIONS
  Higher-order corneal wavefront aberrations stabilized 1 year after PRK to treat myopia or myopic astigmatism. The effect of induced corneal HOAs tended to increase after correction of high myopia with large pupils, although without degrading the image optical quality of the cornea over the long term.
authors.affiliation: IRCCS Fondazione G.B. Bietti, Rome, Italy.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Serrao
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lombardo
authors.forename: Pietro
authors.initials: P
authors.lastname: Ducoli
authors.forename: Marco
authors.initials: M
authors.lastname: Lombardo
mesh_terms: D057128:Aberrometry; D000328:Adult; D001251:Astigmatism / Q000601:surgery*; D003315:Cornea / Q000503:physiopathology*; D019781:Corneal Topography; D057108:Corneal Wavefront Aberration / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D047728:Myopia, Degenerative / Q000503:physiopathology / Q000601:surgery*; D018903:Photorefractive Keratectomy; D011680:Pupil / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology