title: Scheimpflug-Placido topographer and optical low-coherence reflectometry biometer: repeatability and agreement.
abstract: OBJECTIVE
  To assess the repeatability of common measurements with the Sirius Scheimpflug-Placido topographer and Lenstar LS900 optical low-coherence reflectometry (OLCR) biometer and the limits of agreement (LoA) between the devices.
  
  
  METHODS
  Eye Hospital of Wenzhou Medical College, Wenzhou, China.
  
  
  METHODS
  Comparative evaluation of a diagnostic test or technology.
  
  
  METHODS
  One randomly healthy eye of subjects was scanned 3 times with both devices. The parameters assessed were central corneal thickness (CCT), anterior chamber depth (ACD) from the corneal epithelium and from the endothelium, mean keratometry (K), and white-to-white (WTW) corneal diameter. The repeatability of scans was calculated using the within-subject standard deviation after 1-way analysis of variance was performed. The agreement between devices was assessed using the Bland-Altman LoA method, which equals the mean difference between devices ± 1.96 × standard deviation of the differences. The mean of 3 scans of each device was used to assess the LoA.
  
  
  RESULTS
  Forty subjects were evaluated. The repeatability of the Scheimpflug-Placido topographer and OLCR biometer was 3.10 μm and 3.32 μm for CCT, 0.04 mm and 0.05 mm for WTW corneal diameter, and 0.17 D and 0.10 D for mean K, respectively. The repeatability for both devices was 0.02 mm for the ACD from the corneal epithelium and the ACD from the corneal endothelium. On Bland-Altman LoA analysis, all parameters were within clinically acceptable limits.
  
  
  CONCLUSIONS
  Both devices had excellent repeatability for all parameters assessed. Good LoAs were found between the 2 devices, indicating they can be used interchangeably for the parameters assessed.
authors: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical College, Wenzhou, Zhejiang, China.
authors: Wuhe
authors: W
authors: Chen
authors: Colm
authors: C
authors: McAlinden
authors: Konrad
authors: K
authors: Pesudovs
authors: Qinmei
authors: Q
authors: Wang
authors: Fan
authors: F
authors: Lu
authors: Yifan
authors: Y
authors: Feng
authors: Jie
authors: J
authors: Chen
authors: Jinhai
authors: J
authors: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000867:Anterior Chamber / Q000033:anatomy & histology*; D001699:Biometry / Q000295:instrumentation*; D003315:Cornea / Q000033:anatomy & histology*; D019781:Corneal Topography / Q000295:instrumentation*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D010781:Photography / Q000295:instrumentation*; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult