title: Repeatability, Reproducibility, and Comparability of Subjective and Objective Measurements of Intraocular Forward Scattering in Healthy Subjects.
abstract: OBJECTIVE
  To assess the repeatability, reproducibility, and comparability of measurements of subjective and objective forward scattering in healthy subjects.
  
  
  METHODS
  We prospectively examined twenty eyes of 20 healthy volunteers (7 men and 13 women; ages, 28.4 ± 4.1 years). The logarithmic straylight value (log(s)) and the objective scattering index (OSI) were measured with a straylight meter (C-Quant) and a point-spread function meter (OQAS), respectively.
  
  
  RESULTS
  The 95% limits of agreement (LoA) between first and second measurements ranged from -0.211 to 0.207 for the C-Quant and from -0.302 to 0.477 for the OQAS. The intraclass correlation coefficients for the repeatability of the log(s) and OSI measurements were 0.815 and 0.926, respectively. The mean difference between examiners was -0.051 ± 0.133 (95% LoA; -0.311 to 0.209) for the C-Quant and 0.080 ± 0.307 (-0.522 to 0.682) for the OQAS. There was a modest, but significant, correlation between the log(s) and the OSI (Spearman correlation coefficient r = 0.498, p = 0.026).
  
  
  CONCLUSIONS
  The C-Quant and the OQAS provide good repeatability and reproducibility, although the OQAS measurement provides a slightly higher ICC than the C-Quant measurement. The subjective forward scattering may be to some extent expressed in the objective forward scattering in healthy subjects.
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa 252-0374, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Iijima
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa 252-0374, Japan.
authors.forename: Kimiya
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa 252-0374, Japan.
authors.forename: Hidenaga
authors.initials: H
authors.lastname: Kobashi
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa 252-0374, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Saito
authors.affiliation: Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa 252-0374, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kamiya
mesh_terms: D000328:Adult; D003941:Diagnostic Techniques, Ophthalmological / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D014792:Visual Acuity / Q000502:physiology*; D055815:Young Adult