title: Introduction of corneal astigmatism through placement of a scleral fixation ring in eye bank eyes.
abstract: OBJECTIVE
  To determine the effect of scleral fixation ring placement in induction of astigmatism by topographic analysis.
  
  
  METHODS
  Baseline measurements were used in human eyes from the Utah Lions Eye Bank. In two control eyes, the effect of placing and replacing the eye in the holder was determined. In nine eyes, the effect of placing a 14-mm ring 2.0-mm from the limbus and an 18-mm ring 4.0-mm from the limbus, both in line with and between the rectus muscles, was determined. Induced astigmatism (IA) was determined by Alpins' vector analysis method.
  
  
  RESULTS
  Control eyes had a mean variation of 0.26 +/- 0.18 diopters (D) (range, 0.07-0.65). The study eyes had a mean IA of 1.55 D with statistically significant differences noted when comparing 14-mm rings (0.92 +/- 2.00 D) versus 18-mm rings in line with the rectus (3.02 +/- 1.49 D; p = 0.02), with 18-mm rings in line with the rectus muscles (3.02 +/- 1.46 D) versus between the muscles (1.37 +/- 1.14 D; p = 0.03), and all measurements with the 14-mm ring (1.0 +/- 1.49 D) versus the 18-mm ring (2.14 +/- 1.51 D; p = 0.04.).
  
  
  CONCLUSIONS
  Significant IA can occur with placement of fixation rings, especially when suture placement is near the insertions of the rectus muscles.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Rudd
authors.forename: J
authors.initials: J
authors.lastname: Weis
authors.forename: R
authors.initials: R
authors.lastname: Connors
authors.forename: R J
authors.initials: RJ
authors.lastname: Olson
mesh_terms: D001251:Astigmatism / Q000175:diagnosis / Q000209:etiology*; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D005125:Eye Banks; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000009:adverse effects*; D012590:Sclera; D014019:Tissue Donors