The role of UVA rays in skin aging.

Chronic sun exposure causes photoaging of human skin, a process that is characterized by clinical, histological and biochemical changes which differ from alterations in chronologically aged but sun-protected skin. Within recent years substantial progress has been made in unraveling the underlying mechanisms of photoaging [1]. A question of great importance has been: Which parts of the sunlight cause which feature of photoaging? Ultraviolet [...]