Photoaging's portrait: the road map towards its photoprotection.

Two factors clearly hamper a better assessment of the efficiency of photoprotection of the sun-induced cutaneous aging: short durations (months) of the studies with regard the global fate of photoaging by decades and the number of studied subjects, limited to hundreds for practical reasons. The methodology based on the automatic analysis of facial signs through selfies images could theoretically by-pass both factors, allowing thousands of subjects to be studied along years.