Direct and non-direct measurement techniques for analysis of skin surface topography

Estimation of skin smoothness is of ever-increasing interest especially in the field of cosmetic research. There are some established methods for asse ssing skin smoothness, e.g. optical and mechanical profilometry, but the pr esentation of recently developed new methods reflects the demand for altern atives which are more precise and practical. For fundamental research on ul trastructure of the stratum corneum surface scanning electron microscopy is a suitable method. A direct method is the surface evaluation of living ski n, which is based on an optical system in a CCD camera measuring four param eters of roughness, scaling, smoothing and wrinkling. A similar but non-dir ect method is optical profilometry using skin replicas. Laser profilometry produces a variety of data which can be analysed using complex mathematical functions. A promising new method is transparency profilometry (skin visio meter) using a very thin skin print which allows parallel light to pass thr ough and is analysed immediately after production. The different methods ca n be used for characterization of the skin microrelief in dermatoses or for dynamic measurements of time-dependent changes in skin surface topography after application of cosmetic or medical products.