The case for enhanced facial zone mapping to create targeted skin care
Women are becoming increasingly concerned about how attractive they look. This concern has lead to appearance enhancements through topical skin care products, devices (eg micro-needling), minimally invasive procedures and surgery. Advances in the qualitative mapping of the skin in different facial zones is essential for the improved efficacy of these products and interventions.
Targeting the signs of ageing that are most relevant to consumers represents the first step in functional skin care. Eye movement-tracking research confirms people’s preferences when judging the age and attractiveness of female faces. The attractiveness of a face impacts on age-rating accuracy; attractive faces are rated younger than their true age and younger faces are, in turn, perceived as more attractive. These judgments are linked to fixations primarily on the eye region, as well as the nose and mouth. Procter & Gamble cites the forehead, the under eye area and the lips as the three most important areas in “youthfulness and attractiveness preference scoring” of the ageing Caucasian face.
It is known that both skin surface topography (lines and wrinkles) and colour distribution drive perception of age and health. Perception of age is more strongly related to skin surface topography. Among my Caucasian clients, facial wrinkles are a greater concern than uneven skin colour distribution, which can be covered by make-up.
Research in the Russian Caucasian population confirms that the three main features impacting the perception of age are skin topography on the forehead (the wrinkle depth of the glabella) and the eye region (crow’s feet), and lines on the upper lip. Only one feature relates to skin colour: the severity of brown spots, which is important when scoring the face for ageing. Therefore, targeting the wrinkles – frown lines, crow’s feet and lip lines – seems to be most efficacious when enhancing facial appearance. This has been well proven by the popularity of make-up, Botox and fillers in these areas. Research into the ageing of British women (45-65 years old) judged by American and German men, has confirmed that wrinkle modifications on the forehead and around the eyes shows the highest difference in youthfulness ratings. In these areas, the participants were able to detect at least a 20% visual change in skin surface topography. Fortunately, even these small changes affect perceptions of facial age and attractiveness. Hence, functional skin care and devices (like micro-needling patches) can, at least in the short term, deliver results that are visible and can be appreciated by familiar audiences, for instance partners, family members and friends.
The traditional approach to facial zones has been simple: differentiating the t-zone as an area with high sebum secretion and the u-zone as an area with low sebum in combination skin types, and paying more attention to the ageing of the eye, lip and neck areas of facial skin. The first study to characterise skin types through biophysical and skin imaging techniques established that different skin types had different characteristics related to skin texture, oiliness and barrier function. However, complete facial mapping of biophysical skin parameters of all distinct facial zones has been, due to its complexity, carried out only recently. Continuous colour maps can visualise patterns of these parameters in the face.
The first mapping of skin hydration and skin barrier measured skin capacitance and TEWL (transepidermal water loss) on 30 pre-defined sites on the face (forehead, cheek, jaw and eye areas); interpolated between each measured value; and superimposed these on the digital images of a face to show remarkable gradients in distinct facial zones. However, functional maps of other biophysical skin parameters (eg sebum content, skin blood flow, pH, temperature and bacterial flora) that examine distinct inter-regional differences are still missing. Research studies cannot be compared with each other because each uses different anatomical sites, measurement techniques and protocols. Establishing a standardised biophysical profile of the human face is essential for the future of anti-ageing skin care. Further, some facial areas are more easily irritated than others by environmental stimuli, or more often affected by skin conditions. Understanding these predispositions will lead to better therapeutics in dermatology.
Skin care innovations based on detailed understanding of facial zone parameters in different age groups and skin types are more likely to be clinically successful. Significant regional- and age-dependent differences are observable in stratum corneum functions on the face. In general, the barrier function increases with age due to a decreased epidermal turnover rate as reflected in the increase of the corneocyte size.
The forehead, nose and chin show higher sebum levels and skin type induced variability. Skin surface lipids are richest on the nose with low superficial pH demonstrating good skin barrier. The t-zone and perioral area also have a higher blood flow and average temperature due to a dense network of blood vessels. Therefore, a smart moisturising system or a primer that alleviates the midday shine caused by a circadian rhythm in sebum production would be beneficial to people with oily and combination skin types. As the chin pH and TEWL is higher and the area is more prone to acne as well as sensitivity due to skin barrier disruption, targeted patches to prevent pre-menstrual flares are recommended. However, the glabella wrinkles develop due to frowning, and proven interventions, such as rollers, massage and facial exercises, complement skin care in delaying their onset.
The skin in the eye zone is gentle and sensitive. The eyelid skin is different from other zones because of the low level of skin surface lipids and a thin stratum corneum composed of large corneocytes. This results in a high surface hydration state but poor barrier function. The vermillion borders of the lips covered by an exposed part of the oral mucosa exhibit remarkably poor barrier function and low hydration state. It is the interplay between skin hydration and skin openness that needs to be addressed in these areas with targeted delivery.
Taking into consideration the movement of the mouth and eye orbicular muscles, the advent of micro-needling patch technology loaded with hyaluronic acid (Radara) in combination with skin barrier function-supporting active ingredients and facial exercises, promises good clinical results in treating crow’s feet and lip lines.
Exaggerated nasolabial lines have an ageing effect. Facial skin of the nasolabial and chin areas has poor barrier function. Also, skin hydration tends to be lower at the nasolabial fold and the corneocytes are smaller than those on the cheek. This suggests the presence of mild invisible inflammation. This part of the face also easily develops sensitivity to cosmetics and dermatitis due to external agents. Given the role of facial expression and fat-related cheek sagging, it is not surprising that this is the area that also concerns my clients.
Technological advances in skin research now allow for a quantitative study of the biophysical qualities of the face. The understanding of delicate site-dependent differences in skin zones builds a data framework for tailor-made interventions. A combination of skin care products, micro-needling patches, devices, facial massage and exercises guarantee effectiveness and consumer satisfaction when targeting skin care in different skin types. Personalised skin care should take into consideration genetics and lifestyle, and employ sophisticated facial diagnostics. Comprehensive facial maps are a long awaited dataset that will help clinicians and manufacturers address consumer anti-ageing needs with confidence.
Author: Katerina Steventon
Dr Katerina Steventon is a skin scientist and columnist with experience of working at the interface of commercial, clinical and research health care sectors. Her research interests are skin health, appearance and ageing. She specialises in difficult-to- treat skin types and innovative perspectives on consumer needs in facial skin care.
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