Functional and morphological studies of photodamaged skin on the hands of middle-aged Japanese golfers

The skin of golfers' hands provides a suitable model to study the effect of chronic sun exposure, because one of their hands is exposed to the outer e nvironment, especially sunlight, while the other one is always protected by a glove during play. Our purpose was to find out the influence of photodam age on the properties of the skin surface of middle-aged Japanese by using non-invasive methods. We measured hydration state, and water barrier functi on of the stratum corneum (SC) and the color of the skin of the dorsum of t he hands. In a separate study, we evaluated the skin surface contour by usi ng replicas taken from the skin in a slightly stretched or relaxed position . We found a significant decrease in hydration of the skin surface of the e xposed skin as compared to that of the protected skin, whereas no such diff erence was found with transepidermal water loss, a parameter for water barr ier function of the SC. Luminance of skin color was also reduced in the sun -exposed skin. Replica analysis revealed that large wrinkles developing in a relaxed position were more prominent on the exposed than on the protected skin, while fine furrows noted in a slightly stretched position were shall ower on the former than the latter. The data obtained indicate that the chr onically exposed skin of golfers' hands shows morphological and functional changes resulting from long time exposure to the outer environment especial ly sunlight. Furthermore, bioengineering non-invasive methods are found to be useful to detect early photodamage of the skin in a more quantitative fa shion which is rather difficult to demonstrate clinically.