title: Femtosecond-Assisted Arcuate Keratotomy for the Correction of Postkeratoplasty Astigmatism: Vector Analysis and Accuracy of Laser Incisions.
abstract: OBJECTIVE
  To assess the clinical and refractive outcomes of femtosecond-assisted arcuate keratotomy in postkeratoplasty patients, and the accuracy of the incisions, using optical coherence tomography.
  
  
  METHODS
  This is a retrospective study of patients with high postkeratoplasty astigmatism. Patients with a minimum of 4 diopters (D) of postkeratoplasty regular astigmatism were included. The main outcome measures were corrected distance visual acuity, keratometry, corneal topography, and the depth of corneal incisions. Arcuate keratotomy procedures were performed using the IntraLase Femtosecond laser. The depth of keratotomies was set to 75% of the thinnest pachymetry.
  
  
  RESULTS
  Twenty eyes of 20 patients were recruited in this study. The mean age at surgery was 51 years, and the mean follow-up period was 17 ± 7.9 months. The corrected distance visual acuity improved significantly from 20/60 preoperatively to 20/41 after surgery (P = 0.004). The mean preoperative and postoperative spherical equivalents were -4.34 ± 2.91 D and -4.44 ± 3.64 D, respectively (P = 0.49). The mean keratometric cylinder decreased from 9.45 ± 2.97 D (range, 4.2-15.2 D) to 4.64 ± 2.79 D (range, 1.4-11.8 D) (P < 0.001). There was no statistical difference between the mean surgical-induced astigmatism and the mean target-induced astigmatism (P = 0.313). The mean difference between the scheduled and actual incision depth was 10.5 ± 22.2 μm (P = 0.057). No complications occurred during the procedures.
  
  
  CONCLUSIONS
  Femtosecond-assisted keratotomy seems to be a safe and efficient technique for the reduction of large amounts of corneal astigmatism. Although overcorrection and undercorrection may occur, the visual outcome is satisfactory. Optical coherence tomography analysis reports a good predictability of the depth of incisions.
authors.affiliation: Department of Ophthalmology, Quinze-Vingts National Hospital, Pierre and Marie Curie University, Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Loriaut
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Borderie
authors.forename: Laurent
authors.initials: L
authors.lastname: Laroche
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000209:etiology / Q000601:surgery*; D003315:Cornea / Q000601:surgery*; D003316:Corneal Diseases / Q000601:surgery; D063171:Corneal Pachymetry; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000009:adverse effects*; D007646:Keratotomy, Radial / Q000379:methods*; D053685:Laser Therapy; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011183:Postoperative Complications / Q000601:surgery*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult