title: LASIK for spherical refractive myopia: effect of topographic astigmatism (ocular residual astigmatism, ORA) on refractive outcome.
abstract: OBJECTIVE
  In eyes with a preoperative plano refractive cylinder, it would appear that there is no rationale for astigmatic treatment. The aim of this retrospective, cross-sectional data analysis was to determine the amount of topographic astigmatism in refractive plano eyes that results in reduced efficacy after myopic laser in situ keratomileusis (LASIK).
  
  
  METHODS
  This study included 267 eyes from 267 consecutive myopic patients with a refractive plano cylinder. Receiver operating characteristic analysis was used to find the cut-off values of preoperative ocular residual astigmatism (= topographic astigmatism) that can best discriminate between groups of efficacy and safety indices in preoperative plano refractive cylinder eyes.
  
  
  RESULTS
  Preoperative ocular residual astigmatism (ORA) (or topographic astigmatism) of ≤0.9 diopters (D) resulted in an efficacy index of at least 0.8 statistically significantly more frequently than eyes with a preoperative ORA of >0.9 D. Eyes with a high ORA preoperatively also had a high ORA postoperatively. Regression analysis showed that each diopter of preoperative ORA reduced efficacy by 0.07.
  
  
  CONCLUSIONS
  A preoperative corneal astigmatism of ≥0.9 D could (partially) be taken into account in the LASIK design, even if the subjective refractive astigmatism is neutral.
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Andreas
authors: A
authors: Frings
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Gisbert
authors: G
authors: Richard
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Johannes
authors: J
authors: Steinberg
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Christos
authors: C
authors: Skevas
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Vasyl
authors: V
authors: Druchkiv
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Toam
authors: T
authors: Katz
authors: Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany.
authors: Stephan J
authors: SJ
authors: Linke
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001251:Astigmatism / Q000150:complications*; D003315:Cornea / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000150:complications / Q000601:surgery*; D012372:ROC Curve; D012029:Refraction, Ocular; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult