title: Femtosecond laser-assisted keratoplasty: full and  partial-thickness cut wound strength and endothelial  cell loss across a variety of wound patterns.
abstract: OBJECTIVE
  To evaluate wound strength for patient safety during transport and endothelial viability when partial and complete femtosecond laser-assisted keratoplasty (FLAK) incisions are made in cadaveric corneas.
  
  
  METHODS
  19 human corneoscleral rims were divided into six groups, mounted on an anterior chamber maintainer and cut with a femtosecond laser programmed to the following patterns: 'zigzag' (A), 'mushroom' (B) and 'top hat' (C) in both full (1) and partial (2) thicknesses. The pressure required to produce leakage from the corneal incision was then measured. Eight additional corneas were cut with the 'zigzag' pattern: four full and four partial thickness, prepared and transported per standard eye bank protocol, and analysed for endothelial cell loss with trypan blue staining and digital image analysis.
  
  
  RESULTS
  Mean leakage pressure in mm Hg for group A1 was 110 (SD 94); group A2, 1180 (SD 468); group B1, 978 (SD 445); group B2, 987 (SD 576); group C1, 710 (SD 474); group C2, 1290 (SD 231). There was a significant difference in leakage pressure between groups A1 and A2 (p=0.05), groups A1 and B1 (p=0.05), and groups A1 and C1 (p=0.05). Mean percentage endothelial damage after full-thickness cuts was 8.40 (SD 2.34) and 5.30 (SD 1.33) in partial-thickness cuts (p=0.11).
  
  
  CONCLUSIONS
  Partial thickness zigzag, top hat and mushroom-style partial FLAK incisions left an intact tissue wall with high resistance to rupture, whereas full-thickness cuts were more variable. Laser trephination and eye bank handling protocol for donor FLAK buttons leads to moderate peripheral endothelial cell loss in tissue with both complete and partial cuts.
authors.forename: Kamden R
authors.initials: KR
authors.lastname: Kopani
authors.forename: Michael A
authors.initials: MA
authors.lastname: Page
authors.forename: Jeff
authors.initials: J
authors.lastname: Holiman
authors.forename: Armando
authors.initials: A
authors.lastname: Parodi
authors.forename: Bernie
authors.initials: B
authors.lastname: Iliakis
authors.forename: Winston
authors.initials: W
authors.lastname: Chamberlain
mesh_terms: D000368:Aged; D000867:Anterior Chamber / Q000378:metabolism; D004396:Coloring Agents / Q000378:metabolism; D003315:Cornea / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery*; D055954:Corneal Endothelial Cell Loss / Q000473:pathology*; D048988:Corneal Surgery, Laser / Q000379:methods*; D005125:Eye Banks; D006801:Humans; D007429:Intraocular Pressure; D015948:Keratoplasty, Penetrating / Q000379:methods*; D008875:Middle Aged; D010539:Permeability; D012421:Rupture; D013529:Surgical Wound Dehiscence / Q000378:metabolism / Q000503:physiopathology*; D014019:Tissue Donors; D014343:Trypan Blue / Q000378:metabolism; D014945:Wound Healing
chemical_list: D004396:Coloring Agents; D014343:Trypan Blue