OBJECTIVE AND SUBJECTIVE SKIN SURFACE EVALUATION 337 goal is to be able to use these parameters to predict clinical response and/or consumer perception. The results of the present study represent a significant step towards reaching that goal. The roughness parameters Ra and Rz appear to be the most useful for the character- ization of the general topography of the skin. It is important to remember that "rough- ness" here is used in the context of the metals industry and not in terms of skin condition perception. An increase in these parameters correlated with plumpness scores obtained from evaluation of SEM photomicrographs and have been taken to be a positive indicator of skin condition. These results are consistent with SEM work t•y Wolfram et al. (16) who reported a "pronounced swelling of the major subdivisions" as a result of hydrating human skin in vivo. This interpretation is not in agreement with surface profile analyses reported by Nicolls et al. (8) or Cook (10) who reported a decrease in roughness parameters (assessed as a "smoothing") after treatment with emollient lotions. A large part of this discrepancy may be accounted for by material deposited in the furrows resulting in a smoother profile with little change in the skin surface itself. This interpretation is supported by SEM analysis by ourselves and others (17, 19). In addition, it has been reported that some changes in plumping and moisturization were not detectable at the level of the stratum corneum, but were reflections of deeper changes (19). It is possible that the parameters measured here more accurately reflect those changes. If plumping is in fact a result of changes beneath the stratum corneum, it is not surprising that is would not correlate with cracking or flaking, which are a reflection of surface damage. This would be consistent with the results of this study. This current study is one of the few to have directly compared surfanalysis to a visual evaluation of normal skin. We are currently investigating the relationship between plumpness and the tactile perception of smoothness and softness. To our knowledge this report is unique in the ability to objectively evaluate a sample for cracks, one of the hallmarks of "chapped" skin. The advances mentioned above in combination with the capacity to take consecutive replicas of the same site (14) will allow the effects of cosmetic agents to be quantitated. Results of preliminary investi- gations suggest that this technique can be used to evaluate wash-off products, i.e., soaps as well as leave-on products. ACKNOWLEDGEMENTS The authors thank James R. Swafford and William P. Sharp, Department of Botany and Microbiology, Arizona State University, for their excellent technical assistance with the scanning electron microscopy, and Robert W. Washam II for assistance with.the statistical analysis. REFERENCES (1) D. R. Highley, V. O. Savoyak, J. J. O'Neill, and J. B. Ward, A stereomicroscopic method for the determination of moisturizing efficacy in humans, J. Soc. Cosmet. Chem., 27, 351-363 (1976). (2) C. Wagner and R. W. Goltz, Human cutaneous topography, Cutis, 23, 830-842 (1979). (3) R. J. Marshall and R. Marks, Assessment of skin surface by scanning densitometry of macrophoto- graphs, Clin. Exp. Dermatol., 8, 121-127 (1983). (4) P. T. Pugliese, Instrumental techniques for evaluating the performance of skin care products, Drug and Cosmetic Industry, 125, 32-34, 78 (1979).

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