title: Wavefront-guided laser epithelial keratomileusis with the wavelight concept system 500.
abstract: OBJECTIVE
  Laser epithelial keratomileusis (LASEK) is a technique of refractive surgery for treatment of myopia. More than 90% of patients are within the intended correction of +/-0.50 diopters (D), without any unwanted side effects. After conventional refractive surgery, higher-order aberrations are induced. To reduce these aberrations, we used wavefront-guided ablation.
  
  
  METHODS
  Twenty patients with visual problems in ambient light were included. The primary surgery was 141 to 463 days before the retreatment. LASEK was performed with the Camellin technique with 20% EtOH for 30 seconds. Before surgery, the root mean square (RMS) values were measured and the laser treatment was performed with the WaveLight Concept System 500 (WaveLight Laser Technologie AG). The preoperative spherical equivalent refraction was -1.22 D (SD 0.57 D) and the astigmatism was -0.42 D (SD 0.25 D). Preoperatively and 6 months postoperatively, a comprehensive examination was performed.
  
  
  RESULTS
  All retreatments were performed without any intra- or postoperative complications. All patients reported an improvement of vision. The 6-month postoperative refraction was 0.25 D (SD 0.36 D). RMS decreased significantly from 0.72 to 0.47. RMS fourth order also decreased significantly from 0.60 to 0.30 and the spherical aberration decreased significantly from 0.57 to 0.28.
  
  
  CONCLUSIONS
  In earlier studies, patients reported reduction of contrast vision, even after resurgery. Our patients showed a significant reduction of higher-order aberrations and better contrast vision after retreatment with wavefront guided LASEK. Retreatment with wavefront-guided LASEK has the potential to correct night vision problems after excimer laser surgery.
authors.affiliation: Rayne Institute, Department of Ophthalmology, St. Thomas' Hospital, London, UK. christoph.wvm@web.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Winkler von Mohrenfels
authors.forename: Andrea
authors.initials: A
authors.lastname: Huber
authors.forename: Bernhard
authors.initials: B
authors.lastname: Gabler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Herrmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Kempe
authors.forename: Christof
authors.initials: C
authors.lastname: Donitzky
authors.forename: Chris P
authors.initials: CP
authors.lastname: Lohmann
mesh_terms: D019781:Corneal Topography; D006801:Humans; D049008:Keratectomy, Subepithelial, Laser-Assisted / Q000009:adverse effects; D009216:Myopia / Q000503:physiopathology / Q000601:surgery; D011446:Prospective Studies; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D054140:Refractive Surgical Procedures; D012086:Reoperation; D013997:Time Factors; D016896:Treatment Outcome; D014792:Visual Acuity