title: Clinical grading of post-LASIK ectasia related to visual limitation and predictive factors for vision loss.
abstract: OBJECTIVE
  To evaluate and characterize the main clinical features of post-laser in situ keratomileusis (LASIK) ectasia, propose a grading system based on visual limitation, and identify predictive factors related to the degree of visual loss.
  
  
  METHODS
  Vissum Corp., Alicante, Spain.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  This study comprised consecutive eyes with corneal ectasia after LASIK from 1996 to 2010. Main outcomes were post-LASIK ectasia corrected distance visual acuity (CDVA), CDVA loss, spherical equivalent (SE), and the corneal bulge (delta K). These outcomes were correlated with the residual stromal bed, ablation depth, ablation ratio (ablation depth:pachymetry), corneal depth (flap + ablation depth), and corneal ratio (corneal depth:pachymetry) to characterize their role in the severity of the disease.
  
  
  RESULTS
  The mean post-LASIK ectasia CDVA, CDVA loss, SE, and delta K were 0.20 logMAR ± 0.18 (SD), -0.13 ± 0.15 logMAR, -3.80 ± 3.86 diopters (D), and 4.77 ± 4.23 D, respectively. The ablation ratio had the strongest correlation with post-LASIK ectasia CDVA (ρ = 0.477 and P<.001), whereas the corneal ratio had the strongest correlation with the post-LASIK ectasia SE and delta K (ρ = -0.614 and ρ = 0.453, respectively: P<.001). The ablation ratio was the main predictive factor for post-LASIK ectasia CDVA loss (relative risk, 2.04; P=.049).
  
  
  CONCLUSIONS
  The grading system based on visual limitation was consistently represented by differences in CDVA loss, SE, and delta K. A high amount of tissue removed by the refractive procedure was associated with greater corneal biomechanical destabilization, increased corneal steepening, and a worse prognosis.
authors.affiliation: Vissum Instituto Oftalmologico de Alicante, Alicante, Spain.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Brenner
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Alió
authors.forename: Alfredo
authors.initials: A
authors.lastname: Vega-Estrada
authors.forename: Julio
authors.initials: J
authors.lastname: Baviera
authors.forename: Jaime
authors.initials: J
authors.lastname: Beltrán
authors.forename: Rosario
authors.initials: R
authors.lastname: Cobo-Soriano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003316:Corneal Diseases / Q000145:classification* / Q000209:etiology / Q000503:physiopathology; D063171:Corneal Pachymetry; D019781:Corneal Topography; D004108:Dilatation, Pathologic / Q000145:classification / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000145:classification / Q000209:etiology / Q000503:physiopathology; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D011183:Postoperative Complications; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D013524:Surgical Flaps; D014786:Vision Disorders / Q000145:classification* / Q000209:etiology / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult