title: Intra-individual variability of penetrating keratoplasty outcome after excimer laser versus motorized corneal trephination.
abstract: OBJECTIVE
  To assess the intra-individual variability of outcomes after penetrating keratoplasty by comparing mechanical and nonmechanical corneal trephination.
  
  
  METHODS
  Fifteen patients (30 eyes, 16 with keratoconus and 14 with Fuchs' dystrophy; median age at penetrating keratoplasty 56.3/53.5 years) were assessed whose trephination was performed using a motor trephine in one eye and the 193-nm excimer laser (MEL 60, Carl Zeiss-Meditec) in the other eye by one experienced surgeon. Subjective refractometry, standard keratometry, and corneal topography were used to assess best spectacle-corrected visual acuity (BSCVA); spherical equivalent refraction; keratometric and topographic central corneal power; refractive, keratometric, and topographic astigmatism; surface regularity index; surface asymmetry index; and potential visual acuity preoperatively, before first suture removal (at 1 year), and at last available follow-up after final suture removal but before additional surgery (1.3 and 1.9 years, respectively).
  
  
  RESULTS
  Before first suture removal BSCVA was significantly higher (0.7 vs 0.5; P=.008) after excimer laser trephination. At the end of follow-up, refractive/ keratometric/topographic astigmatism (2.20/2.10/2.40 diopters [D] vs 5.00/6.00/7.10 D) and surface regularity index (0.8 vs 1.1) were significantly lower (P=.02, P=.005, P=.01, and P=.03, respectively) and potential visual acuity was significantly higher (0.9/0.6; P=.02) after excimer laser trephination.
  
  
  CONCLUSIONS
  During long-term follow-up, all-sutures-out postkeratoplasty astigmatism and surface regularity are superior in the eye where nonmechanical excimer laser was applied in contrast to the fellow eye with motor trephination in the same individual.
authors.affiliation: Department of Ophthalmology, Friedrich Alexander University of Erlangen-Nürnberg, Erlangen, Germany. nszentmary@hotmail.com
authors.forename: Nóra
authors.initials: N
authors.lastname: Szentmáry
authors.forename: Achim
authors.initials: A
authors.lastname: Langenbucher
authors.forename: Gottfried O H
authors.initials: GO
authors.lastname: Naumann
authors.forename: Berthold
authors.initials: B
authors.lastname: Seitz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000473:pathology / Q000601:surgery*; D003316:Corneal Diseases / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D019781:Corneal Topography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000295:instrumentation*; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D018903:Photorefractive Keratectomy / Q000379:methods*; D011182:Postoperative Care / Q000379:methods*; D011183:Postoperative Complications / Q000517:prevention & control; D012029:Refraction, Ocular; D012086:Reoperation; D016896:Treatment Outcome