title: Clinical outcomes after deep anterior lamellar keratoplasty using the big-bubble technique in patients with keratoconus.
abstract: OBJECTIVE
  To report clinical outcomes of deep anterior lamellar keratoplasty (DALK) using the big-bubble technique in patients with keratoconus.
  
  
  METHODS
  Prospective noncomparative interventional study.
  
  
  METHODS
  
  
  
  METHODS
  Single hospital.
  
  
  METHODS
  Eighty-one unselected consecutive patients with moderate to advanced keratoconus intolerant to contact lenses and with poor spectacle-corrected visual acuity.
  
  
  METHODS
  DALK big-bubble technique.
  
  
  METHODS
  Intraoperative and postoperative complications, postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, corneal topography, and endothelial cell density.
  
  
  RESULTS
  Seventy-eight procedures (96%) were completed as DALK. Big-bubble was achieved in 50 cases (64%); 28 (36%) required manual intrastromal dissection. Intraoperative microperforations occurred in 11 cases (13%). Baseline mean uncorrected visual acuity was 20/500 and 20/60 two years after surgery. Average preoperative BSCVA, was 20/100 and 20/30 at the end of follow-up. Final BSCVA was better in patients in whom big-bubble with exposure of the Descemet membrane was achieved (P < .05). Average keratometry and SD (standard deviation) refraction changed from 62.1 +/- 6.7 diopters and -10.76 +/- 5 diopters to 47.51 +/- 4.73 diopters and -1.81 +/- 3.2 diopters, respectively after surgery. Mean preoperative endothelial cell density was 2202.29 +/- 392.35 cells/mm(2) and 2034 +/- 438.39 cells/mm(2) two years after surgery. Two patients developed stromal rejection.
  
  
  CONCLUSIONS
  The DALK big-bubble technique is a valuable treatment in patients with keratoconus. Visual outcome is comparable to standard penetrating keratoplasty (PK) when formation of big-bubble with exposure of the Descemet membrane (DM) was achieved. Clinically important graft-host interface developed in some cases after manual intrastromal dissection. Stromal rejection is a rare complication.
authors.affiliation: Unità Operativa di Oculistica, Ospedale Maggiore, Largo Nigrisoli 2, 40133 Bologna, Italy. luigi.fontana@ausl.bologna.it
authors.forename: Luigi
authors.initials: L
authors.lastname: Fontana
authors.forename: Gabriella
authors.initials: G
authors.lastname: Parente
authors.forename: Giorgio
authors.initials: G
authors.lastname: Tassinari
mesh_terms: D000328:Adult; D002452:Cell Count; D019781:Corneal Topography; D016039:Corneal Transplantation / Q000379:methods*; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D011183:Postoperative Complications; D011446:Prospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology