Sunlight may have many effects on the skin, and one of the most important both clinically and cosmetically is aging. Many laymen, unaware of the fact that exposure to the harmful ultraviolet rays of sunlight causes aging, are becoming sun fadists. Gross changes in actinically damaged skin are a dry, coarse, leathery appearance, laxity with wrinkling, and various pigmentary changes. Frequently in elderly and even in some relatively young white adults there is a striking difference between light-exposed regions and those protected by clothing. A weather-beaten farmer often appears considerably older than a physician of comparable age.1 Since Negro skin has natural protection in its high melanin content, elderly Negroes often appear deceptively young.
According to Blum, the thickness of the corneal and granular layers is very important in determining the skin's response to the ultraviolet radiation which strikes its surface.2 That these layers must play an important