Efficacy of anti‐wrinkle products in skin surface appearance: a comparative study using non‐invasive methods

Background/purpose: Age has a huge influence on skin roughness; with increasing age, the number of collagen and elastine fibers is reduced and elasticity decreases significantly. Pharmaceutical and cosmetics, environmental factors and lifestyle have an important effect on skin. In this study, the efficacy of 12 commercial anti‐wrinkle products was evaluated using a direct non‐invasive method to measure the skin surface morphology. Four clinical parameters surface evaluation of the living skin (SELS) (Ser, Sesc, Sesm, and Sew) were evaluate using Visioscan^® VC98. Methods: Two hundred and forty‐eight healthy female volunteers, aged between 30 and 70 years, were chosen for this study. The duration of treatment was 28 days. Skin microrelief parameters were evaluated using the Visioscan^® VC98 – SELS 2000 from Courage+Khazaka. Measurements were made in the crow's feet area and the differences were evaluated for statistical significance. Results: Significant differences were found for some of the SELS parameters. According to the results obtained for SELS Sew, products that showed to be more effective against aging were V, M, N, T, P, R and L. We think this methodology may be considered very useful for the direct study of the skin surface and may be suitable as a routine method in wrinkle evaluation.     

Integrated real‐time Raman system for clinical in vivo skin analysis

Background: Raman spectroscopy is a non‐invasive optical technique that can probe the molecular structure and conformation of biochemical constituents. The probability of Raman scattering is exceedingly low (∼10⁻¹⁰), and consequently up to now the practical application of Raman spectroscopy to clinical medicine has been limited by either the weak spectral signal or by the long data acquisition times. Recent advances in Raman hardware and probe design have reduced spectral acquisition times, paving the way for clinical applications. Methods: We present an integrated real‐time Raman spectroscopy system for skin evaluation and characterization, which combines customized hardware features and software implementation. Real‐time data acquisition and processing includes CCD dark‐noise subtraction, wavelength calibration, spectral response calibration, intensity calibration, signal saturation detection, cosmic ray rejection, fluorescence background removal, and composition modeling. Real‐time in vivo Raman measurement of volar forearm skin is presented to illustrate the methods and modeling. Results: The system design implemented full‐chip vertical hardware binning to improve the signal‐to‐noise ratio by 16‐fold. The total time for a single in vivo measurement with analysis can be reduced to 100 ms with this implementation. Human skin was well modeled using the base Raman spectra. Conclusion: In vivo real‐time Raman can be a very promising research and practical technique for skin evaluation.     

Colorimetric analysis of pigmented skin lesions: a pilot study with the Visi-Chroma™ VC-100 device

BACKGROUND: Definition of the colour of pigmented skin lesions (PSLs) with the naked eye remains subjective and may be influenced by lighting. This problem underlines the usefulness of instrumental assessments such as epiluminescence microscopy and colorimetric devices. OBJECTIVE AND METHODS: We describe here a new method of colour analysis of PSLs with the Visi-Chroma VC-100 device, which illuminates the surface of the skin with white light-emitting diodes (LEDs) and analyses the reflected light by a red-green-blue (RGB) charge-coupled device (CCD) colour camera. Twenty-one PSLs to be excised for cosmetic or medical reasons were analysed by this device with clinicopathological correlation. CONCLUSIONS: This method is feasible and might be useful to assess the colour of PSLs and allow comparisons for changes over time. Further studies are needed to determine the usefulness of this device in clinical practice.     

Physical measurement and evaluation of skin color changes under normal condition and post‐ultraviolet radiation: a comparison study of Chromameter CM 2500d and Maxmeter MX18

Objective: To compare the data correlation between two kinds of instruments, Chromameter CM2500d and Maxmeter MX18, in the measurement of skin color changes under normal condition and post‐ultraviolet (UV) radiation. Method: The data points of Chromameter CM2500d are based on L^*a^* values, while Maxmeter MX18 are based on M and E values, in order to compare the data correlation between these two kinds of instruments in skin color measurement on both non‐exposed and exposed sites. In addition, an evaluation of the correlation of post‐UV irradiation between these two instruments was conducted. Four different kinds of parameters post‐UV radiation were measured including minimal erythema dose (MED), immediate pigmentation dose (IPD), minimal persistent pigmentation dose (MPPD) and repeated UV radiation. The following UV radiation dosages were applied as Day 1=1.0 MED, Day 2=0.5 MED and Day 3=0.5 MED for repeated UV radiation, of which the erythema and pigmentation changes were recorded. Result: Chromameter CM2500d and Maxmeter MX18 showed good data correlation when measuring both non‐exposed and exposed sites on normal skin. L^* values were affected more easily by UV‐induced erythema than M values on skin color changes after 1 MED and repeated UV exposures. IPD, MPPD and the pigmentation data showed good correlations with the measurement of the intensive erythema formation induced by repeated UV exposures. a^* value was shown to be equally effective as E value with skin erythema measurements in response to various MEDs. However, increased erythema induced by repeated UV radiations was able to reduce the correlations between a^* and E values. On the other hand, a^* and E were shown to be equally effective in recording the erythema change courses after strong erythema responses post‐UV radiations. Conclusion: This comparative study showed that the data correlations between the two kinds of instruments were different depending on measurement conditions. Both Chromameter CM2500d and Maxmeter MX18 instrumental measurement results should be carefully evaluated by experimental conditions.     

In vivo skin measurements with a novel probe head for simultaneous skin impedance and near‐infrared spectroscopy

Background/purpose: Near‐infrared (NIR) spectroscopy and skin impedance (IMP) measurements are useful techniques for objective diagnostics of various skin diseases. Here, we present a combined probe head for simultaneous, time‐saving NIR spectroscopy and skin impedance measurements. The probe also ensures that both measurements are performed under equal conditions and at the same skin location. Methods: Finite element method simulations were performed for evaluation of the impedance. In vivo skin measurements were performed and combined NIR and impedance spectra were analysed by means of multivariate methods with respect to body location, age and gender. The classification rate was determined by a planar discriminant analysis. Reproducibility was investigated by calculation of scatter values and statistical significance between overlapping groups was assessed by the calculation of intra‐model distances, q. Results: The novel probe yielded rapid reproducible results and was easy to manage. Significant differences between skin locations and to a lesser extent age groups and gender were demonstrated. Conclusion: With the novel probe, statistically significant differences between overlapping classes in score plots can be confirmed by calculating intra‐model distances. The influence of molecular differences in the skin at different body locations is larger than the influence of gender or age and therefore relevant reference measurements are discussed.