A recent article published in the Russian journal Engineering explores the utility of low-coherence interferometry to detect optical properties in skin in vivo to measure the penetration of moisturizing gels.
According to the authors (translated via Google), modern automated optoelectronics make it possible to noninvasively obtain data on the optical parameters of investigated substances that interact with the skin tissue and penetrate to certain depths. One example is the low-coherent interferometric method (NKIM).
Briefly, as the article explains, this approach is based on the analysis of light radiation reflected from the test substance to study the morphological and functional state of skin after it interacts with said substance. The present work sought to develop the theoretical and practical aspects of this interaction to measure the optical parameters of skin in vivo in response to modern moisturizing face gels.
The results provided information on the penetration rate of gels. For example, one product was found to penetrate to a depth of 300 microns after 3 hr, after which skin returned to its original state. Other products, however, did not show this return to skin's original state, suggesting further action between the gel and tissue. The authors note that measurements of this type can significantly expand the possibilities of cosmetics research.