title: Comparison of ablation centration after bilateral sequential versus simultaneous LASIK.
abstract: OBJECTIVE
  To compare ablation centration after bilateral sequential and simultaneous myopic LASIK.
  
  
  METHODS
  A retrospective randomized case series was performed of 670 eyes of 335 consecutive patients who had undergone either bilateral sequential (group 1) or simultaneous (group 2) myopic LASIK between July 2000 and July 2001 at the China Medical University Hospital, Taichung, Taiwan. The ablation centrations of the first and second eyes in the two groups were compared 3 months postoperatively.
  
  
  RESULTS
  Of 670 eyes, 274 eyes (137 patients) comprised the sequential group and 396 eyes (198 patients) comprised the simultaneous group. Three months post-operatively, 220 eyes of 110 patients (80%) in the sequential group and 236 eyes of 118 patients (60%) in the simultaneous group provided topographic data for centration analysis. For the first eyes, mean decentration was 0.39 +/- 0.26 mm in the sequential group and 0.41 +/- 0.19 mm in the simultaneous group (P = .30). For the second eyes, mean decentration was 0.28 +/- 0.23 mm in the sequential group and 0.30 +/- 0.21 mm in the simultaneous group (P = .36). Decentration in the second eyes significantly improved in both groups (group 1, P = .02; group 2, P < .01). The mean distance between the first and second eyes was 0.31 +/- 0.25 mm in the sequential group and 0.32 +/- 0.18 mm in the simultaneous group (P = .33). The difference of ablation center angles between the first and second eyes was 43.2 < or = 48.3 degrees in the sequential group and 45.1 +/- 50.8 degrees in the simultaneous group (P = .42).
  
  
  CONCLUSIONS
  Simultaneous bilateral LASIK is comparable to sequential surgery in ablation centration.
authors.affiliation: Department of Ophthalmology, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Jane-Ming
authors.initials: JM
authors.lastname: Lin
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Tsai
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects / Q000379:methods*; D008297:Male; D009216:Myopia / Q000601:surgery; D012086:Reoperation; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity