Experimental 193-nm excimer laser trephination with divergent cut angles in penetrating keratoplasty

Berthold Seitz, Ashley Behrens, Achim Langenbucher, Murat M. Kus, Gottfried O.H. Naumann

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Purpose. To study the morphologic properties of divergent cut angles after nonmechanical trephination for penetrating keratoplasty in donors and recipients and to assess its implications for donor-recipient stability in an experimental porcine model. Methods. An excimer laser 193-nm corneal trephination was performed in 30 enucleated porcine eyes by using a modified 'open mask' (stainless steel sheet 10CrNi18), to obtain round donor buttons and corresponding recipient beds 7 mm in diameter at the level of Bowman's layer. An automated globe-rotation device allowed different cut angles toward the optical axis. Three cut angles were intended: 0°, 15°divergent, and 35°divergent. Quality of the cuts was assessed by means of histology and scanning electron microscopy (SEM). In a different setting, after alignment of the donor button and corresponding recipient bed in an artificial anterior chamber, intracameral pressure was increased stepwise, modifying the height of a bottle of balanced saline solution connected to the chamber. Criterion for 'instability' was the movement of the donor button in all four quadrants during observation with a surgical microscope (x12). Results. Reproducible cut angles and smooth cut surfaces of donors and recipients were confirmed by histologic and SEM evaluation. Macroscopically, a good alignment of a divergent donor button in a corresponding recipient bed was achieved. Instability of the donor buttons occurred with a water column niveau at 2 cm in the 0°cut, at 3 cm in 15°divergent cuts, and at 4.5 cm in 35°divergent cuts. Conclusion. The stability of a corneal donor button in a recipient bed seems to increase in proportion with the degree of divergence of the trephination angle. Considering the good histologic quality and macroscopic alignment obtained, divergent cut angles may allow a reduction of sutures, assuring a watertight wound closure in penetrating keratoplasty.

Original languageEnglish (US)
Pages (from-to)410-416
Number of pages7
Issue number4
StatePublished - 1998
Externally publishedYes


  • Divergent cut angle
  • Donor
  • Excimer laser
  • Morphological properties
  • Nonmechanical trephination
  • Penetrating keratoplasty
  • Recipient stability
  • Suture technique

ASJC Scopus subject areas

  • Ophthalmology


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