Microrelief of the skin using a light transmission method

The recently developed Skin Visiometer, based on light transmission through blue-coloured silicone replicas, was used to study skin microrelief, Calib rated metal plates displaying lines with depths between 6 and 361 mum, were used to determine the accuracy, sensitivity and reproducibility of the tec hnique as well as the parameters of importance during measurement, The prec ision of the measurements was particularly good between 10 mum and 361 m mu . The sensitivity of the method was between 10 and 20 mum. Replicas of vola r forearm skin were taken from four groups (n = 15) of male and female volu nteers in the age ranges 20 to 30 years and 55 to 65 years. In addition to the instrumental roughness parameters (Rz, Rt, Rm and Ra), the surface of t he furrows, the number of primary and secondary lines and the number of int ersections were determined, For both sexes, significantly lower values were observed for Rz, Rm and Rt in the younger age group than in the older age group, In addition, the numbers of primary and secondary lines and the numb er of intersections were higher, pointing to a more structured microrelief in younger forearm skin. Diurnal rhythm, the relative humidity of the measu ring room and the position of the forearm were found to be significant fact ors, while room temperature and pre-cleansing of the skin with mild product s mere not, Following the application of a hydrating cream (twice daily for 14 days) to the forearm skin of the older female age group, the Rz, Rt, Rm and Re decreased, while the other parameters measured, except for the surf ace taken in by the lines, increased, indicating that the microrelief was m odified towards the typical pattern observed in young skin.