Epsilon™ – Corneometer® Correlations

The Epsilon™ and the Corneometer® use similar capacitance sensing methods and should therefore respond in similar ways to to both materials of different dielectric permittivity (in-vitro test) and skin of different hydration (in-vivo test). The results of two such tests, as published in [1], are shown below.


1. In-vitro Correlation


The in-vitro test used a number of solvents (water, Propylene Glycol, Butanol, Heptanol, Decanol) and air in direct contact with the sensors. The solvent layers used were thick enough to ensure that the electric fields from the sensors were fully contained within them. For the Epsilon™, a central region of the sensor was used, together with a Region of Interest to exclude areas of the sensor not covered by the solvents. For the Corneometer, the entire 7mm square sensor area was covered with solvent. The measurements, shown on the left, correlate with R=0.97.


2. In-vivo Correlation

For the in-vivo test, volar forearm skin sites of three healthy volunteers (20 – 30 years old) were hydrated for 30 minutes by contact with wet tissue paper, after which they were patted well dry. Measurements were performed at baseline and 0, 10, 20 and 30 minutes after patting dry. The measurements, shown on the left, correlate with R=0.89.


The results show that the linearised permittivity response of the Epsilon™ maps convincingly onto the capacitance response of the Corneometer®.



[1] W Pan, X Zhang, E Chirikhina & P Xiao. Skin Hydration Measurement Using Contact Imaging. Poster Presentation, SCC Annual Scientific Meeting & Technology Showcase, New York 2014. Click here to download in pdf format.