Assessment of visibility of facial wrinkle reduction by various types of observers

The prime objective of many facial wrinkle-reduction treatments is to achieve visible improvement. Thus the visibility of before/after treatment differences is often part of an efficacy assessment. This paper investigates whether the background knowledge of the people acting as observers in such assessments is of impact on the results: e.g. the subjects themselves are familiar with their faces, skin professionals have much experience in judging skin quality, and thus both might be more sensitive to small changes. In a clinical study 44 Female subjects were regularly treated during a period of 12 weeks with one of three wrinkle-reduction methods: K, Land M (placebo). Photographs were taken before treatment and at 6 and 12 weeks. The photographs were judged by 3 types of observers:ㆍ24 Lay observers were given the 0＆6-week and the 0＆12-week photo pairs of all subjects to indicate the one with the least wrinkles in a two-alternative forced-choice (TAFC) procedure.ㆍThe subjects themselves were given the 0＆6-weel and the 0＆12-week pair of their own photos (8 replications) to indicate the photo with the least wrinkles (TAFC).ㆍA trained panel of skin professionals (N=3) each gave 9-point Fitzpatrick wrinkle-severity scores for all individual 0-week and 12-week photos. We found that the lay observers perceived the same differences as the subjects themselves: significant improvements after 12 weeks for treatment K (p<0.0005 and p=0.005, respectively), no visible effects for treatments Land M, and, most importantly, a significant difference between treatments K and M/placebo (p=0.02 and p=0.04, respectively). Also the trained panel found this difference between K and M (p=0.013), but here it was due to a significant deterioration over time of the 'placebo-treated' wrinkles (M, p=0.03). Thus in conclusion we have found no indications that extra knowledge - in the form of familiarity with the own face or in the form of professional training - results in the identification of more treatments that show significantly visible wrinkle-reduction.