title: Influence of the difference between corneal and refractive astigmatism on LASIK outcomes using solid-state technology.
abstract: OBJECTIVE
  To evaluate the influence of the difference between preoperative corneal and refractive astigmatism [ocular residual astigmatism (ORA)] on outcomes obtained after laser in situ keratomileusis (LASIK) surgery for correction of myopic astigmatism using the solid-state laser technology.
  
  
  METHODS
  One hundred one consecutive eyes with myopia or myopic astigmatism of 55 patients undergoing LASIK surgery using the Pulzar Z1 solid-state laser (CustomVis Laser Pty Ltd, currently CV Laser) were included. Visual and refractive changes at 6 months postoperatively and changes in ORA and anterior corneal astigmatism and posterior corneal astigmatism (PCA) were analyzed.
  
  
  RESULTS
  Postoperatively, uncorrected distance visual acuity improved significantly (P < 0.01). Likewise, refractive cylinder magnitude and spherical equivalent were reduced significantly (P < 0.01). In contrast, no significant changes were observed in ORA magnitude (P = 0.81) and anterior corneal astigmatism (P = 0.12). The mean overall efficacy and safety indices were 0.96 and 1.01, respectively. These indices were not correlated with preoperative ORA (r = -0.15, P = 0.15). Furthermore, a significant correlation was found between ORA (r = 0.81, P < 0.01) and PCA postoperatively, but not preoperatively (r = 0.12, P = 0.25). Likewise, a significant correlation of ORA with manifest refraction was only found postoperatively (r = -0.38, P < 0.01).
  
  
  CONCLUSIONS
  The magnitude of ORA does not seem to be a predictive factor of efficacy and safety of myopic LASIK using a solid-state laser platform. The higher relevance of PCA after surgery in some cases may explain the presence of unexpected astigmatic residual refractive errors.
authors.affiliation: *Department of Ophthalmology (Oftalmar), Medimar International Hospital, Alicante, Spain; †Foundation for the Visual Quality (FUNCAVIS, Fundación para la Calidad Visual), Alicante, Spain; and ‡Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain.
authors.forename: David P
authors.initials: DP
authors.lastname: Piñero
authors.forename: David
authors.initials: D
authors.lastname: Ribera
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Pérez-Cambrodí
authors.forename: Pedro
authors.initials: P
authors.lastname: Ruiz-Fortes
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Blanes-Mompó
authors.forename: Antonio
authors.initials: A
authors.lastname: Alzamora-Rodríguez
authors.forename: Alberto
authors.initials: A
authors.lastname: Artola
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology*; D003315:Cornea / Q000503:physiopathology*; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery*; D012029:Refraction, Ocular / Q000502:physiology*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult