title: New Scheimpflug camera device in measuring corneal power changes after myopic laser refractive surgery.
abstract: OBJECTIVE
  To assess the accuracy of a combined Scheimpflug camera-Placido disk device (Sirius, CSO, Italy) in evaluating corneal power changes after myopic photorefractive keratectomy (PRK).
  
  
  METHODS
  Two hundred and thirty-seven eyes of 237 patients that underwent myopic PRK with a refractive error, measured as spherical equivalent, ranging from -10.75 D to -0.5D (mean -4.63 ± 2.21D), were enrolled in this study. Corneal power evaluation using Sirius were performed before, 1, 3 and 6 months after myopic PRK. Mean simulated keratometry (SimK) and mean pupil power (MPP) were measured. Correlations between changes in corneal power, measured with SimK and MPP, and variations in subjective refraction, calculated at corneal plane, were evaluated using Pearson test at every follow up; differences between preoperative and postoperative data were evaluated with the Student paired t-test.
  
  
  RESULTS
  A good correlation has been detected between the variations in subjective refraction measured at corneal plane 1, 3 and 6 months after myopic PRK and both SimK (R(2) = 0.8463; R(2) = 0.8643; R(2) = 0.7102, respectively) and MPP (R(2) = 0.6622; R(2) = 0.5561; R(2) = 0.5522, respectively) but corneal power changes are statistically undervalued for both parameters (p < 0.001).
  
  
  CONCLUSIONS
  Even if our data should be confirmed in further studies, SimK and MPP provided by this new device do not seem to accurately reflect the changes in corneal power after myopic PRK.
authors.affiliation: Multidisciplinary Department of Medical, Surgical and Dental Sciences, Seconda Università di Napoli, Napoli, Italy; Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy. Electronic address: mic.lanza@gmail.com.
authors.forename: Michele
authors.initials: M
authors.lastname: Lanza
authors.affiliation: Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Iaccarino
authors.affiliation: Centro Grandi Apparecchiature, Seconda Università di Napoli, Napoli, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Cennamo
authors.affiliation: Multidisciplinary Department of Medical, Surgical and Dental Sciences, Seconda Università di Napoli, Napoli, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lanza
authors.affiliation: Istituto Clinico Città di Brescia, Brescia, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Coen
mesh_terms: D000293:Adolescent; D000328:Adult; D063171:Corneal Pachymetry; D019781:Corneal Topography; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008875:Middle Aged; D009216:Myopia / Q000175:diagnosis* / Q000601:surgery*; D010781:Photography / Q000295:instrumentation*; D018903:Photorefractive Keratectomy / Q000295:instrumentation*; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D055815:Young Adult
keywords: IOL calculation; Myopic refractive surgery; Scheimpflug camera