title: Comparison of topographic corneal irregularity after LASIK and intrastromal corneal ring segments in the same patients.
abstract: OBJECTIVE
  To retrospectively compare the irregularity of the corneal surfaces of 14 patients after LASIK in 1 eye and placement of intrastromal corneal ring segments (ICRS) in the other eye.
  
  
  METHODS
  In a within-patient comparison, Orbscan corneal topography was used to retrospectively compare the corneal surface irregularity of LASIK-treated and ICRS-treated eyes at an outpatient tertiary-care ophthalmology clinic in Sao Paulo, Brazil. For the anterior corneal surface, irregularity measurements were compared for both the central and peripheral areas of the cornea. The differences between each group were analyzed for statistical significance.
  
  
  RESULTS
  The corneal surfaces of eyes treated with ICRS were found to be more irregular than the corneal surfaces of eyes treated with LASIK, the mean irregularity being 1.91 for LASIK-treated eyes and 3.12 for ICRS-treated eyes in the anterior corneal surface and 0.51 for LASIK-treated eyes and 0.87 for ICRS-treated eyes in the posterior corneal surface. A statistically significant difference was noted only in the posterior surfaces.
  
  
  CONCLUSIONS
  When measured with Orbscan topography, ICRS-treated eyes show more corneal surface irregularity than LASIK-treated eyes. The difference in outcome for the two types of treatment may be due to the mechanical effect of the ICRS on the shape of the cornea.
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Scottsdale, AZ 85259, USA.
authors.forename: Ayman
authors.initials: A
authors.lastname: Naseri
authors.forename: Adriana S
authors.initials: AS
authors.lastname: Forseto
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Francesconi
authors.forename: David G
authors.initials: DG
authors.lastname: Hwang
authors.forename: Mauro
authors.initials: M
authors.lastname: Campos
authors.forename: Walton
authors.initials: W
authors.lastname: Nose
mesh_terms: D001251:Astigmatism / Q000209:etiology / Q000473:pathology*; D003315:Cornea / Q000473:pathology*; D003319:Corneal Stroma / Q000601:surgery*; D019781:Corneal Topography; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D009216:Myopia / Q000601:surgery*; D011183:Postoperative Complications; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012029:Refraction, Ocular; D012189:Retrospective Studies