title: Photorefractive keratectomy with aspheric profile of ablation versus conventional photorefractive keratectomy for myopia correction: six-month controlled clinical trial.
abstract: OBJECTIVE
  To analyze ocular wavefront error and corneal asphericity (Q) in patients treated with aspheric profile photorefractive keratectomy (PRK) compared with patients having conventional PRK to correct myopia and myopic astigmatism and to evaluate the effect of postoperative corneal shape on visual performance.
  
  
  METHODS
  Eye Clinic, University G. d'Annunzio, Chieti-Pescara, Italy.
  
  
  METHODS
  Fifty eyes were treated with aspheric profile PRK using the MEL 80 flying-spot excimer laser, and 24 eyes were treated with standard PRK using the MEL 70 flying-spot excimer laser.
  
  
  RESULTS
  Postoperative wavefront error increased in both groups. Six months after surgery, there was a smaller increase in root mean square (RMS) of total higher-order aberrations and spherical aberration (59% and 106%, respectively) in the aspheric profile PRK group than in the conventional PRK group (94% and 136%, respectively) (P<.01). The aspheric profile PRK group showed more prolate corneal asphericities (mean Q of 0.15 +/- 0.26) than the conventional group (mean Q of 0.45 +/- 0.26) (P<.001), with increasing oblateness for higher attempted corrections. A higher percentage of patients with better low-contrast uncorrected visual acuity and best corrected visual acuity was observed in the aspheric PRK group than in the conventional PRK group (P<.05).
  
  
  CONCLUSIONS
  Aspheric profile and conventional PRK were safe and efficient for the correction of myopia and myopic astigmatism. Moreover, aspheric profile PRK induced a smaller increment of total wavefront error, was related to a smaller increase in spherical aberration, and better maintained the physiology of the corneal surface than conventional treatment.
authors.affiliation: Department of Medicine and Science of Ageing Eye Clinic University G. D'Annunzio, Chieti-Pescara, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mastropasqua
authors.forename: Lisa
authors.initials: L
authors.lastname: Toto
authors.forename: Eduardo
authors.initials: E
authors.lastname: Zuppardi
authors.forename: Mario
authors.initials: M
authors.lastname: Nubile
authors.forename: Paolo
authors.initials: P
authors.lastname: Carpineto
authors.forename: Marta
authors.initials: M
authors.lastname: Di Nicola
authors.forename: Enzo
authors.initials: E
authors.lastname: Ballone
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery*; D003315:Cornea / Q000601:surgery*; D006801:Humans; D054018:Lasers, Excimer; D009216:Myopia / Q000601:surgery*; D018903:Photorefractive Keratectomy / Q000379:methods*; D011183:Postoperative Complications; D016896:Treatment Outcome; D014792:Visual Acuity