title: Calibration of trephine blade depth.
abstract: OBJECTIVE
  To assess the accuracy and precision of the Barron radial vacuum trephine as an instrument for corneal lamellar dissection.
  
  
  METHODS
  We describe a practical method to calibrate individual trephines prior to lamellar corneal procedures using the calibration microscope designed for diamond knives.
  
  
  RESULTS
  We observed that one turn (360 degrees) of the trephine produced a mean blade displacement of 0.25 mm. However, individual trephines demonstrated a significant range of variability.
  
  
  CONCLUSIONS
  For highly accurate trephination, it is useful to calibrate each individual trephine using the calibration microscope.
authors.affiliation: Federal University of Sao Paulo, Paulista School of Medicine.
authors.forename: P
authors.initials: P
authors.lastname: Schor
authors.forename: E
authors.initials: E
authors.lastname: Rocha
authors.forename: D P
authors.initials: DP
authors.lastname: Cheema
authors.forename: D
authors.initials: D
authors.lastname: Miller
mesh_terms: D002138:Calibration; D003315:Cornea / Q000601:surgery; D003316:Corneal Diseases / Q000601:surgery; D006801:Humans; D007646:Keratotomy, Radial / Q000295:instrumentation*; D013525:Surgical Instruments / Q000592:standards*