title: Influence of stromal refractive index and hydration on corneal laser refractive surgery.
abstract: OBJECTIVE
  To evaluate the influence of the stromal refractive index and hydration on postoperative outcomes in eyes that had corneal laser refractive surgery using the Amaris laser system.
  
  
  METHODS
  Augenzentrum Recklinghausen, Recklinghausen, Germany.
  
  
  METHODS
  Comparative case series.
  
  
  METHODS
  At the 6-month follow-up, right eyes were retrospectively analyzed. The effect of the stromal refractive index and hydration on refractive outcomes was assessed using univariate linear and multilinear correlations.
  
  
  RESULTS
  Sixty eyes were analyzed. Univariate linear analyses showed that the stromal refractive index and hydration were correlated with the thickness of the preoperative exposed stroma and was statistically different for laser in situ keratomileusis and laser-assisted subepithelial keratectomy treatments. Univariate multilinear analyses showed that the spherical equivalent (SE) was correlated with the attempted SE and stromal refractive index (or hydration). Analyses suggest overcorrections for higher stromal refractive index values and for lower hydration values.
  
  
  CONCLUSIONS
  The stromal refractive index and hydration affected postoperative outcomes in a subtle, yet significant manner. An adjustment toward greater attempted correction in highly hydrated corneas and less intended correction in low hydrated corneas might help optimize refractive outcomes.
  
  
  BACKGROUND
  Mr. Magnago and Dr. Arba-Mosquera are employees of and Dr. Diego de Ortueta is a consultant to Schwind eye-tech-solutions GmbH & Co. KG. Mr. Rüden has no financial or proprietary interest in any material or method mentioned.
authors.affiliation: From Augenzentrum Recklinghausen (De Ortueta, Rüden) Recklinghausen, and Schwind eye-tech-solutions GmbH & Co. KG (Magnago, Arba Mosquera), Kleinostheim, Germany; Recognized Research Group in Optical Diagnostic Techniques (Arba Mosquera), University of Valladolid, Valladolid, Spain. Electronic address: ortueta@gmx.de.
authors.forename: Diego
authors.initials: D
authors.lastname: de Ortueta
authors.affiliation: From Augenzentrum Recklinghausen (De Ortueta, Rüden) Recklinghausen, and Schwind eye-tech-solutions GmbH & Co. KG (Magnago, Arba Mosquera), Kleinostheim, Germany; Recognized Research Group in Optical Diagnostic Techniques (Arba Mosquera), University of Valladolid, Valladolid, Spain.
authors.forename: Dennis
authors.initials: D
authors.lastname: von Rüden
authors.affiliation: From Augenzentrum Recklinghausen (De Ortueta, Rüden) Recklinghausen, and Schwind eye-tech-solutions GmbH & Co. KG (Magnago, Arba Mosquera), Kleinostheim, Germany; Recognized Research Group in Optical Diagnostic Techniques (Arba Mosquera), University of Valladolid, Valladolid, Spain.
authors.forename: Thomas
authors.initials: T
authors.lastname: Magnago
authors.affiliation: From Augenzentrum Recklinghausen (De Ortueta, Rüden) Recklinghausen, and Schwind eye-tech-solutions GmbH & Co. KG (Magnago, Arba Mosquera), Kleinostheim, Germany; Recognized Research Group in Optical Diagnostic Techniques (Arba Mosquera), University of Valladolid, Valladolid, Spain.
authors.forename: Samuel
authors.initials: S
authors.lastname: Arba Mosquera
mesh_terms: D000328:Adult; D000368:Aged; D001834:Body Water / Q000378:metabolism*; D003319:Corneal Stroma / Q000378:metabolism / Q000503:physiopathology* / Q000601:surgery; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology / Q000601:surgery; D049008:Keratectomy, Subepithelial, Laser-Assisted / Q000379:methods*; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult