AGE-RELATED-CHANGES IN THE ELASTIC PROPERTIES AND THICKNESS OF HUMAN FACIAL SKIN

Using recently designed, commercially available, non-invasive instrume nts, we measured the thickness and elasticity of the skin of the face and ventral forearm in 170 women, and evaluated the effects of age and exposure to sunlight. Skin thickness decreased with age in ventral fo rearm skin, which has limited exposure to sunlight, but increased sign ificantly in the skin of the forehead, corners of the eyes, and cheeks , which are markedly exposed to sunlight. Skin elasticity (U-r/U-f) de creased with age on both the face and forearm. The ratio of viscosity element to elasticity element (U-v/U-e) increased with age at all site s. However, delayed distension (U-v), immediate retraction (U-r), fina l distension (U-f), and immediate distention (U-e), as individual elem ents, decreased on the face and increased on the forearm with age. Thi s tendency was more marked after correction for skin thickness. These results suggested the specificity of skin thickness and elasticity in the facial skin. Analysis using a four-element model showed no changes in the elasticity coefficient of Maxwell element on the forearm, but an increase on the face. This indicates quantitative or qualitative ch anges in elastic fibres in facial skin. Thus, sunlight appears to have a considerable effect on the thickness and physical properties of fac ial skin.