Positional differences and aging changes in Japanese woman epidermal thickness and corneous thickness determined by OCT (optical coherence tomography)

Background/purpose A number of studies of the internal structure of Japanese woman's skin are now performed by means of optical coherence tomography (OCT) as a technique capable of visualizing the internal structure in a non-invasive manner. Methods We measured the epidermal and corneous thicknesses at 11 sites in 116 healthy female volunteers aged from teens to sixties to examine possible positional differences and aging changes. Results The epidermal thickness determined at the 11 sites averaged 68.6 ± 23.0 μm (mean ± SD) and the corneous thickness averaged 14.1 ± 1.80 μm, the values of which were thinner than those presented in conventional textbooks on the subject. It was also revealed that, with advancing age, the epidermal thickness becomes less at some sites but showed no change at other sites, and the comparison between age groups suggested that a thinning trend is generally observed up to the thirties with no continuous changes thereafter. Conclusion Aging changes in the epidermis appeared to occur in the granular to basal layers, and the results obtained by OCT, which can viably determine the skin thickness, seemed to be very important for understanding the skin more accurately.