title: Circular keratotomy for the correction of astigmatism.
abstract: BACKGROUND
  Mathematical and physical considerations that are contained in Gauss' law lead to the concept of a circular cut for the correction of corneal astigmatism.
  
  
  METHODS
  The method applied is the coupling of the aspheric corneal surface to the spherical obturator of the Guided Trephine System and cutting of 90% of the parenchyma. Nineteen human eyes were treated with this technique, using a double-running suture closure.
  
  
  RESULTS
  Results of reduction of astigmatism can regularly be obtained but are of different amounts depending on the origin of astigmatism. Mean preoperative refractive astigmatism was 5.41 diopters and mean postoperative refractive astigmatism was 1.34 D. Six eyes required additional tranverse arcuate keratotomy.
  
  
  CONCLUSIONS
  The procedure is effective, but the results are variable. It may be improved by the use of obturators that fit the radius of curvature of the cornea.
authors.affiliation: Department of Ophthalmology, Marien Hospital, Bochum, Germany.
authors.forename: J H
authors.initials: JH
authors.lastname: Krumeich
authors.forename: A
authors.initials: A
authors.lastname: Knuelle
mesh_terms: D001251:Astigmatism / Q000601:surgery*; D003315:Cornea / Q000502:physiology; D005500:Follow-Up Studies; D006801:Humans; D007646:Keratotomy, Radial / Q000379:methods*; D008433:Mathematics; D013536:Suture Techniques; D016896:Treatment Outcome