title: Comparison of anterior chamber depth measurements of Nidek AL-Scan and Galilei Dual Scheimpflug Analyzer.
abstract: OBJECTIVE
  We aimed to compare anterior chamber depth (ACD) measurements between the Nidek AL-Scan and the Galilei Dual Scheimpflug Analyzer.
  
  
  METHODS
  Turgut Ozal University Medical Faculty, Ankara, Turkey.
  
  
  METHODS
  Prospective masked bilateral randomized study.
  
  
  METHODS
  Sixty-three individual patient eyes with normal ocular examination findings and no prior ocular surgery were analyzed. Paired two-tailed t-test was used to evaluate agreement between devices. Interobserver repeatability was evaluated in 22 patients using intraclass correlation coefficient (ICC) and Bland-Altman analysis.
  
  
  RESULTS
  The mean ± standard deviation (SD) ACD for Nidek and Galilei was 3.57 ± 0.29 (range from 2.92 to 4.32) and 3.65 ± 0.29 (range from 3.01 to 4.40), respectively. Comparing the two instruments using paired samples t-test, a statistically significant difference was found between the measurements obtained for ACD (P = 0). Two observers' intraclass correlation coefficients (ICC) were 0.996 for Nidek and 0.968 for Galilei. For Nidek, ACD mean difference was 0mm (P < 0.001); 95% limits of agreement was from -0.05 to 0.05. For Galilei ACD mean difference was -0.01 mm (P < 0.001); 95% limits of agreement was from -0.14 to 0.12. The Galilei Dual Scheimpflug Analyzer measured longer ACD values than the Nidek AL-Scan.
  
  
  CONCLUSIONS
  This comparative study showed that the difference in ACD between the measurements of the Nidek AL-Scan and the Galilei Dual Scheimpflug Analyzer was statistically significant but clinically it was negligible. Further studies are needed, especially on IOL calculation formulas that include ACD and its effect on postoperative spherical equivalent values.
authors.affiliation: Turgut Özal University, Ophthalmology Department, Ankara, Turkey. Electronic address: serdarderv@hotmail.com.
authors.forename: Mehmet Serdar
authors.initials: MS
authors.lastname: Dervişoğulları
authors.affiliation: Turgut Özal University, Ophthalmology Department, Ankara, Turkey. Electronic address: ytotan@usa.net.
authors.forename: Yüksel
authors.initials: Y
authors.lastname: Totan
authors.affiliation: Turgut Özal University, Ophthalmology Department, Ankara, Turkey. Electronic address: abguragac@gmail.com.
authors.forename: Betül
authors.initials: B
authors.lastname: Gürağaç
mesh_terms: D000328:Adult; D000869:Anterior Eye Segment / Q000033:anatomy & histology*; D001699:Biometry / Q000295:instrumentation; D003261:Contact Lenses; D063171:Corneal Pachymetry / Q000295:instrumentation*; D019781:Corneal Topography / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography / Q000295:instrumentation*; D017755:Prosthesis Fitting / Q000295:instrumentation*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Anterior chamber depth; Digital Scheimpflug Analyzer; Optical biometer