title: Computerized Scheimpflug densitometry as a measure of corneal optical density after excimer laser refractive surgery in myopic eyes.
abstract: OBJECTIVE
  To evaluate changes in anterior corneal optical density and the refractive index after photorefractive keratectomy (PRK) using a rotating Scheimpflug system.
  
  
  METHODS
  Department of Ophthalmology, University Federico II, Naples, Italy.
  
  
  METHODS
  Comparative case series.
  
  
  METHODS
  Anterior corneal optical density was evaluated with a rotating Scheimpflug system at baseline and 3 months and 12 months after PRK in eyes with a refractive error between -6.00 diopters (D) and -12.00 D (study group). A control group of unoperated eyes with the same refraction range was used to calculate corneal optical density and the Gladstone-Dale constant in unoperated eyes using the Gladstone-Dale formula. In the study group, changes in the anterior corneal optical density were evaluated over time and variations in the anterior corneal refractive index were obtained using the Gladstone-Dale constant.
  
  
  RESULTS
  The study group comprised 37 eyes and the control group, 200 eyes. In the study group, the mean anterior corneal optical density and refractive index, respectively, were 27.71 ± 4.39 and 1.360 ± 0.05 at baseline, 37.812 ± 12.31 and 1.491 ± 0.16 after 3 months (P<.001 compared with baseline), and 26.29 ± 4.93 and 1.341 ± 0.06 after 12 months (P=.03 compared with baseline). The mean corneal optical density in the control group was 27.71 ± 4.31 (SD), and the resultant Gladstone-Dale constant was 0.013.
  
  
  CONCLUSIONS
  An early increase and a subsequent reduction in anterior corneal optical density and the refractive index were present in myopic eyes during 1 year after PRK.
authors.affiliation: Eye Department, University Federico II, Naples, Italy.
authors.forename: Gilda
authors.initials: G
authors.lastname: Cennamo
authors.forename: Raimondo
authors.initials: R
authors.lastname: Forte
authors.forename: Bernardino
authors.initials: B
authors.lastname: Aufiero
authors.forename: Agostino
authors.initials: A
authors.lastname: La Rana
mesh_terms: D000328:Adult; D003315:Cornea / Q000503:physiopathology*; D003720:Densitometry / Q000295:instrumentation; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D010781:Photography / Q000295:instrumentation; D018903:Photorefractive Keratectomy / Q000379:methods*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*