Visual evaluation in vivo of 'complexion radiance' using the C.L.B.T. sensory methodology

Quantification of perception towards facial skin ideal complexion in multiple ethnic populations from clinical imaging cues

OBJECTIVE

Ideal complexion is a perceptual skin quality that is strongly influenced by cultural and ethnic background. The objectives of this study are to quantitatively characterize skin ideal complexion based on clinical image cues and to compare the perceptions of ideal complexion among multiple ethnicities.

METHODS

Facial images of Indian, Chinese, Caucasian and Latino females collected using VISIA®-CR were presented to naïve panels of the same ethnicity following a two-alternative forced choice design and responses on skin "ideal complexion" were obtained from 336 panelists. Panel perception was transformed logistically (d') and projected onto a continuum (ω) following Bradley-Terry model. Image cues including skin color and unevenness, skin shine and surface smoothness, and pigmentary blotches and spots were computed using image analysis and their relationship with ω were evaluated through multiple regression analysis. A novel skin index namely ideal complexion score (ICS) was developed and correlated against age using linear regression. Finally, ICS was applied to evaluate treatment efficacy of a skin brightening kit on 35 female Caucasian subjects.

RESULTS

Panel perception d' showed statistically significant (p < 0.05) correlation with the contrast of image cues for all ethnic panels (R² = 0.74, 0.76, 0.62 and 0.46 for Indian, Chinese, Caucasian and Latino respectively) and strong correlations between perception ω and linear combinations of image cues were observed (R² > 0.88 for all). Main effects of facial image visual cues on ideal complexion were compared: contrast of skin redness and pigmented spots and visual smoothness were important in determining ICS for all ethnicities; skin color unevenness was more pronounced for Indian and Caucasian; skin lightness was important for Indian and Chinese; skin shine was critical for Chinese and Latino; and skin hue angle ranked higher for Caucasian. Correlations between ICS and age were observed for Indian and Caucasian (R² = 0.55) in which ICS decreased as age increased. Twenty-nine percent improvement on ICS was observed after 12 weeks' treatment using the brightening kit compared to the baseline.

CONCLUSION

Mathematical models were successfully established to describe subjective perception towards skin ideal complexion based on objectively measured image cues for multiple ethnicities.

Comprehensive model for characterizing skin translucency by expert grading, panel evaluation and image analysis in a Chinese population

OBJECTIVES

Translucent skin is an attribute widely appreciated by people in East Asian countries. There have been studies in the literature to describe the phenomenon by means of clinical grading, instrumental measurement, and image analysis. However, due to its subjective and complex nature, skin translucency has not been comprehensively and rigorously characterized and modeled, particularly in the Chinese population. This study is to develop a mathematical model that quantitatively describes skin translucency from visual cues objectively measured from the skin.

MATERIALS AND METHODS

The study was designed to characterize and model skin translucency by incorporating expert evaluation, panel perception and image analysis of multiple skin visual attributes in one analysis. Faces of 36 Chinese females aged 18-65 years old were evaluated by a dermatologist to obtain clinical translucency scores. Subject pairs were formed with a relatively high and low translucency score in each pair. Their faces were judged in person by 9 panelists in paired-comparison (2-AFC) fashion to pick a "more translucent skin" from each subject pair. Front-view facial images of the subjects were taken, and multiple color and other visually perceivable skin attributes were measured using image analysis. Bradley-Terry analysis and multiple regressions were performed to correlate the panel choices of "more translucent skin" with the objectively measured skin parameters.

RESULTS

Multiple skin color properties affected the panel choices toward translucent skin. Among them skin tone lightness and skin glossiness had positive effects on skin translucency while the hue, color unevenness, severity of red and dark spots affected it negatively. Subsurface light reflection and skin visual smoothness had some effect but were not statistically significant. A mathematical model was constructed to predict a person's skin translucency from objectively measured skin attributes.

CONCLUSION

The subjective property of skin translucency can be characterized and quantified via a comprehensive modeling process involving clinical grading, panel evaluation, image-based measurement of skin attributes and statistical analysis. A novel skin parameter, Skin Translucency Index (STI) was established which provides a way to measure skin translucency, making it possible to assess treatment efficacy before and after product application.

Defining Skin Quality: Clinical Relevance, Terminology, and Assessment

BACKGROUND

Flawless skin is one of the most universally desired features, and demand for improvements in skin quality is growing rapidly. Skin quality has been shown to substantially impact emotional health, quality of life, self-perception, and interactions with others. Although skin quality improvements are a common end point in studies of cosmeceuticals, they are rarely assessed in clinical studies of other aesthetic treatments and products. Descriptive terminology for skin quality parameters also varies considerably within the aesthetic field, relying on a range of redundant and occasionally contradictory descriptors. In short, skin quality has not been clearly defined.

OBJECTIVE

The goal of this review is to highlight the importance of skin quality to patients and physicians, explore known and unknown factors comprising skin quality, and provide clarity regarding terminology, descriptors, and evaluation tools for assessing skin quality.

MATERIALS AND METHODS

A review of the literature on skin quality was performed without limitation on publication date. Relevant articles are presented.

RESULTS AND CONCLUSION

We propose a framework of attributes contributing to skin quality rooted in 3 fundamental categories-visible, mechanical, and topographical-with the aim to provide information to help guide clinicians and inform future clinical studies.

Human brain activity reflecting facial attractiveness from skin reflection

Facial attraction has a great influence on our daily social interactions. Previous studies have mainly focused on the attraction from facial shape and expression. We recently found that faces with radiant skin appear to be more attractive than those with oily-shiny or matte skin. In the present study, we conducted functional magnetic resonance imaging (fMRI) and psychological experiments to determine the human brain activity that reflects facial attractiveness modulated by these skin reflection types. In the fMRI experiment, female subjects were shown successive images of unfamiliar female faces with matte, oily-shiny, or radiant skin. The subjects compared each face with the immediately preceding face in terms of attractiveness, age, and skin reflection, all based on the skin. The medial part of the orbitofrontal cortex (mOFC) was significantly more active when comparing attractiveness than when comparing skin reflection, suggesting that the mOFC is involved in processing facial attractiveness from skin reflection. In the psychological experiment, attractiveness rating was highest for radiant skin, followed by oily-shiny, and then matte skin. Comparison of the results of these experiments showed that mOFC activation level increased with attractiveness rating. These results suggest that the activation level of the mOFC reflects facial attractiveness from skin reflection.

Facial radiance influences facial attractiveness and affective impressions of faces

Objective

Facial attractiveness has been reported to be influenced by visual features such as facial shape and the colour and texture of the skin. However, no empirical studies have examined the effects of facial skin radiance on facial attractiveness. The present study investigated whether types of skin reflection (i.e. radiant, oily and shiny, and matte) and the position of the reflection on the face influence facial attractiveness and other affective impressions.

Methods

A total of 160 female participants (1) estimated the ages and (2) evaluated attractiveness and other impressions of unfamiliar female faces in a total of seven skin reflection conditions. These conditions incorporated three types of reflection (i.e. radiant, oily and shiny, and matte) and three positions of the reflection on the face (i.e. entire facial skin, only cheeks, and only T‐zone).

Results

The facial images of radiance on entire faces were rated as appearing younger than the facial images of oily shine on entire faces and the matte faces. Attractiveness ratings and other positive impressions increased in the order of the matte (ranked lowest), the oily shine on entire face, and the radiance on entire face (ranked highest) conditions. The reflection position also influenced facial attractiveness: attractiveness ratings and other positive impressions were higher in the radiance on entire face condition than in the radiant cheeks and the radiant T‐zone conditions. Interestingly, the radiant cheek faces were rated more radiant and healthier but less feminine and less bright than the radiant T‐zone faces.

Conclusion

These results suggest that facial radiance enhances facial attractiveness and conveys a wide variety of positive impressions on the observer. The magnitude of the effects of cheek radiance and T‐zone radiance differs across various affective impressions. Nevertheless, the results demonstrate that cheek and the T‐zone radiance both contribute to higher attractiveness and other positive impressions of the radiance on entire faces. We believe that our findings can contribute as a guide to the enhancement of positive facial impressions by means of skin radiance, thereby leading to a better understanding of the value of skincare and base makeup.

Clinical effects of an oral supplement rich in antioxidants on skin radiance in women

Background

Environmental factors impact the skin aging resulting in decrease of skin radiance. Nutrition and particularly antioxidants could help to fight against skin degradation.

Objective

The aim of this study was to evaluate the effects of an oral supplement rich in specific antioxidants, SkinAx^2TM, on the improvement of the skin radiance in women.

Methods

The open-label clinical study enrolled 35 women, aged 40–70, with facial dull complexion. Subjects were supplemented orally with a daily dosage of 150 mg of an antioxidant-rich formulation containing superoxide dismutase-rich melon concentrate, grape seed extract rich in monomers of flavanols, vitamin C, and zinc for 8 weeks. Each subject served as her own control. The C.L.B.T.^™ test has been used to evaluate facial skin coloring (C), luminosity (L), brightness (B), and transparency (T) involved in skin radiance. Facial skin imperfections have been assessed by clinical assessment. Firmness has been evaluated by clinical assessment and cutometer measurement. Finally, an auto-questionnaire has been carried out in order to evaluate the satisfaction of the subjects concerning different parameters involved in skin radiance and the global efficacy of the supplement.

Results

Skin “red pink” and “olive” colors were significantly improved after supplementation (P<0.0001). Luminosity was increased by 25.9% (P<0.0001) whereas brightness and transparency were not affected by the supplementation. Facial skin imperfections were significantly reduced after the antioxidant-rich formulation intake (global reduction: −18.0%; P<0.0001). Indeed, dark circles, redness, and spots significantly diminished after oral treatment. Firmness and elasticity have been shown to be improved. Subjects were globally satisfied by the product (82.4%) and have found improvements on their facial skin. Furthermore, 64.7% reported to look better at the end of the supplementation.

Conclusion

The oral supplement containing the antioxidant-rich formulation was found to improve skin radiance by reducing skin coloring, increasing face luminosity, reducing imperfections, and improving skin firmness in women with dull complexion.

Mécano-Stimulation™ of the skin improves sagging score and induces beneficial functional modification of the fibroblasts: clinical, biological, and histological evaluations

BACKGROUND

Loss of mechanical tension appears to be the major factor underlying decreased collagen synthesis in aged skin. Numerous in vitro studies have shown the impact of mechanical forces on fibroblasts through mechanotransduction, which consists of the conversion of mechanical signals to biochemical responses. Such responses are characterized by the modulation of gene expression coding not only for extracellular matrix components (collagens, elastin, etc.) but also for degradation enzymes (matrix metalloproteinases [MMPs]) and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs]). A new device providing a mechanical stimulation of the cutaneous and subcutaneous tissue has been used in a simple, blinded, controlled, and randomized study.

MATERIALS AND METHODS

Thirty subjects (aged between 35 years and 50 years), with clinical signs of skin sagging, were randomly assigned to have a treatment on hemiface. After a total of 24 sessions with Mécano-Stimulation™, biopsies were performed on the treated side and control area for in vitro analysis (dosage of hyaluronic acid, elastin, type I collagen, MMP9; equivalent dermis retraction; GlaSbox(®); n=10) and electron microscopy (n=10). Furthermore, before and after the treatment, clinical evaluations and self-assessment questionnaire were done.

RESULTS

In vitro analysis showed increases in hyaluronic acid, elastin, type I collagen, and MMP9 content along with an improvement of the migratory capacity of the fibroblasts on the treated side. Electron microscopy evaluations showed a clear dermal remodeling in relation with the activation of fibroblast activity. A significant improvement of different clinical signs associated with skin aging and the satisfaction of the subjects were observed, correlated with an improvement of the sagging cheek.

CONCLUSION

Mécano-Stimulation is a noninvasive and safe technique delivered by flaps microbeats at various frequencies, which can significantly improve the skin trophicity. Results observed with objective measurements, ie, in vitro assessments and electron microscopy, confirm the firming and restructuring effect clinically observed.

The science of dermocosmetics and its role in dermatology

Our increased knowledge of normal skin physiology has ushered in a subtle revolution in cosmetic science. Originally designed as preparations to enhance personal appearance by direct application on to the skin, cosmetics have now taken on a new role in dermatology, through the support of the management of many skin disorders. This evolving role of cosmetics in skin care is primarily due to scientific and technological advancements that have changed our understanding of normal skin physiology and how cosmetics modify its appearance both physically and biologically. The vast array of techniques currently available to investigate skin responsivity to multiple stimuli has brought about a new era in cosmetic and dermocosmetic development based on a robust understanding of skin physiology and its varied responses to commonly encountered environmental insults. Most cosmetic research is undertaken on reconstructed skin models crucial in dermatological research, given the strict ban imposed by the European Union on animal testing. In addition, the design and conduct of trials evaluating cosmetics now follow rules comparable to those used in the development and evaluation of pharmaceutical products. Cosmetic research should now aim to ensure all trials adhere to strictly reproducible and scientifically sound methodologies. The objective of this review is to provide an overview of the multidisciplinary scientific approach used in formulating dermocosmetics, and to examine the major advances in dermocosmetic development and assessment, the safety and regulatory guidelines governing their production and the exciting future outlook for these dermocosmetic processes following good practice rules.

Skin radiance: how to quantify? Validation of an optical method

BACKGROUND/PURPOSE

The aim of this study was to validate an optic device used to measure the quantity of light reflected by the skin, which depends on the brightness of the skin.

METHODS

This apparatus gives three parameters, called Complexion/diffusion (Cd), Cr (Complexion/reflection) and Complexion/specular position (Csp). Measurements were carried out on the forehead (slightly rounded surface) and the cheekbone (angular surface). To estimate the repeatability and the reproducibility of each parameter, two female subjects (one with a dull complexion and the other with a glowing complexion) and three operators participated in the study. To investigate repeatability, each operator performed 10 consecutive measurements on both zones. To investigate inter-investigator reproducibility, the operators performed the measurements alternately. To investigate day-to-day reproducibility, these measures were achieved during three visits at a 2-day interval, at D1, D3 and D5. To estimate the sensitivity and the specificity, 30 females participated in the study (15 in the dull complexion group and 15 in the glowing complexion group).

RESULTS

Cd was repeatable (variation coefficient <20%), day-to-day reproducible on both sites (generally P>0.05) but not inter-investigators reproducible (generally P<0.05). The sensitivity was 93% on the forehead and 80% on the cheekbone; the specificity was 87% on the forehead and 60% on the cheekbone. Cr was repeatable (variation coefficient <5%), day-to-day reproducible (P>0.05) and not inter-investigators reproducible (generally P<0.05). The sensitivity was 93% on the forehead and 80% on the cheekbone; the specificity was 87% on the forehead and 80% on the cheekbone. Csp was not repeatable (variation coefficient >5%) on both the studied zones and for the three investigators.

CONCLUSION

The repeatability and the day-to-day reproducibility were satisfying for the Cd and Cr parameters on both the studied sites. The sensitivity and the specificity were satisfying for both parameters on both sites, except for the specificity of the Cd parameter on the cheekbone. Therefore, this apparatus is suitable to follow-up an evolution on both the studied sites, but we recommend: (a) that the same trained investigator always performs the measurements, (b) to privilege the forehead in particular for a classification (dull or glowing).