W Uter1, M Benz, A Mayr, O Gefeller, A Pfahlberg. 1. Department of Medical Informatics, Biometry and Epidemiology, University of Erlangen, Erlangen, Germany. wolfgang.uter@imbe.med.uni-erlangen.de
Abstract
BACKGROUND/ PURPOSE: Different devices are used for the non-invasive measurement of (constitutive) skin pigmentation in (epidemiological) studies. Reproducibility of measurements with the Chromameter (CM, model CR 300, Minolta, Osaka) and the Reflectometer (RM, Courage & Khazaka, Cologne) has not yet been examined in detail and was addressed in a set of four experiments and studies respectively. METHODS: Regarding the CM, the Y value of the Yxy CIE 1931 colour system was utilized, representing lightness in this colour space, while the RM measured reflectance at 660 nm with a small bandwidth of 20 nm. Both devices measure reflectance on a scale from 0 to 100%, however, in different wavelength ranges. Between 3 and 20 repetitions were performed on standard grey scales and different sets of human volunteers, including RM measurements in a large epidemiological field study. RESULTS: While the coefficient of variation (V) increases and the intraclass correlation coefficient decreases from controlled laboratory to field conditions, reproducibility remained in a range considered acceptable, if adequate study conditions were maintained. In a direct comparison on human skin, V of the RM was significantly smaller than that of the CM. CONCLUSION: Both devices can be used confidently in field studies; however, based on considerations of skin optics and in view of slightly lesser variability, the RM may be preferable.
BACKGROUND/ PURPOSE: Different devices are used for the non-invasive measurement of (constitutive) skin pigmentation in (epidemiological) studies. Reproducibility of measurements with the Chromameter (CM, model CR 300, Minolta, Osaka) and the Reflectometer (RM, Courage & Khazaka, Cologne) has not yet been examined in detail and was addressed in a set of four experiments and studies respectively. METHODS: Regarding the CM, the Y value of the Yxy CIE 1931 colour system was utilized, representing lightness in this colour space, while the RM measured reflectance at 660 nm with a small bandwidth of 20 nm. Both devices measure reflectance on a scale from 0 to 100%, however, in different wavelength ranges. Between 3 and 20 repetitions were performed on standard grey scales and different sets of human volunteers, including RM measurements in a large epidemiological field study. RESULTS: While the coefficient of variation (V) increases and the intraclass correlation coefficient decreases from controlled laboratory to field conditions, reproducibility remained in a range considered acceptable, if adequate study conditions were maintained. In a direct comparison on human skin, V of the RM was significantly smaller than that of the CM. CONCLUSION: Both devices can be used confidently in field studies; however, based on considerations of skin optics and in view of slightly lesser variability, the RM may be preferable.
Authors: Mirte Langeveld; Lara S van de Lande; Eimear O' Sullivan; Berend van der Lei; Joris A van Dongen Journal: Skin Res Technol Date: 2021-11-09 Impact factor: 2.240
Authors: Nadja Nicole Zöller; Matthias Hofmann; Manuel Butting; Igor Hrgovic; Jürgen Bereiter-Hahn; August Bernd; Roland Kaufmann; Stefan Kippenberger; Eva Valesky Journal: Indian J Dermatol Date: 2019 Mar-Apr Impact factor: 1.494