title: Experimental circular keratotomy for correction of corneal astigmatism.
abstract: OBJECTIVE
  To investigate the effect of circular keratotomy depth and diameter on corneal astigmatism.
  
  
  METHODS
  High astigmatism was induced in 25 human donor eyes by an anterior radial 7-0 silk suture across the corneoscleral limbus. With a 6.0, 6.5, 7.0, or 7.5 mm trephine, a 0.3 mm deep circular incision was made in 20 donor eyes. In 5 donor eyes 5 circular incisions were made with a diamond knife set at 0.1, 0.2, 0.3, 0.4, and 0.5 mm depths.
  
  
  RESULTS
  The reduction of astigmatism between the 4 groups in which different trephination diameters were used showed no statistically significant difference (P > .1). The relationship between incision depth and reduction of astigmatism was statistically significant (P < .001).
  
  
  CONCLUSIONS
  Artificially induced corneal astigmatism was reduced by a circular keratotomy in this donor eye model. Deeper incisions showed a greater effect.
authors.affiliation: Department of Ophthalmology, University Hospital Groningen, The Netherlands.
authors.forename: R H
authors.initials: RH
authors.lastname: Wijdh
authors.forename: G
authors.initials: G
authors.lastname: van Rij
mesh_terms: D001251:Astigmatism / Q000473:pathology / Q000601:surgery*; D003315:Cornea / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007646:Keratotomy, Radial / Q000379:methods; D014019:Tissue Donors; D016896:Treatment Outcome