title: In vivo and in vitro analysis of topographic changes secondary to DSAEK venting incisions.
abstract: BACKGROUND
  Descemet's stripping automated endothelial keratoplasty (DSAEK) venting incisions may induce irregular corneal astigmatism. The study examines in vivo and in vitro astigmatic effects of venting incisions.
  
  
  METHODS
  In vivo analysis examined eleven eyes of eleven patients who had received DSAEK with venting incisions. A chart review of the eleven eyes including assessment of pre and postoperative refraction and topography was performed. In vitro analysis examined three cadaver eyes which received topographic imaging followed by venting incisions at 4 mm, 6 mm, and 7 mm optical zones. Topographic imaging was then performed again after the incisions.
  
  
  RESULTS
  Postoperative topographies of eleven eyes demonstrated localized flattening at incision sites and cloverleaf pattern astigmatism. There was a significant difference in corneal irregularity measurement (P = 0.03), but no significant difference in shape factor or change of topographic cylinder. The cloverleaf pattern was found in cadaver eyes with incisions placed at 4 mm and 6 mm optical zones but not at the 7 mm zone.
  
  
  CONCLUSIONS
  DSAEK venting incisions can cause irregular corneal astigmatism that may affect visual outcomes. The authors recommend placement of venting incisions near the 7 mm optical zone.
authors.affiliation: John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA.
authors.forename: Majid
authors.initials: M
authors.lastname: Moshirfar
authors.forename: Monette T
authors.initials: MT
authors.lastname: Lependu
authors.forename: Dane
authors.initials: D
authors.lastname: Church
authors.forename: Marcus C
authors.initials: MC
authors.lastname: Neuffer