106 JOURNAL OF COSMETIC SCIENCE INTRODUCTION Gynoid lipodystrophy (cellulite), the unattractive cottage cheese-like dimpling of the thighs, abdomen, and buttocks, affects 85% of post-adolescent women (1,2). Cellulite treatment is a high priority for the pharmaceutical and cosmetic industries (2-10). Products (11-15), supplements (16), and massage techniques (8,9) purport to treat cellulite, presumably by reducing the appearance of the dimpled, lumpy skin. The uneven skin surface texture is attributed to the three-dimensional (3D) architecture of the hypodermal connective tissue (14, 17-20). In females, fat cell chambers, "papillae adiposae," are sequestered by connective tissue septa, positioned in a radial and arched manner and anchoring the dermis to the muscle fascia. The subcutaneous fat cell chambers bulge into the dermis, thereby changing the skin surface appearance (13). The literature on the etiology of cellulite and the effectiveness of treatments to ameliorate the condition is limited (4,6,14,16,21), given the prevalence. The surface features of cellulite are believed to result when subcutaneous adipose tissue protrudes into the lower reticular dermis, thereby creating irregularities at the epidermal surface. The biomechanical properties of the epidermis and dermis may also influence the severity. Cellulite is not specific to overweight females, but added weight may cause enlargement of the fat lobules, further protrusion into the dermis, and exacerbation of the condition (2, 17). Weight loss is reported to diminish cellulite, but it may not alter the underlying dermal-subcutaneous structures (1 7, 19). Identification of key factors responsible for the visual appearance of cellulite will help to facilitate the development and selection of effective treatments. We conducted a set of noninvasive biophysical measurements of the cellulite-affected tissue and determined the specific factors that contribute to cellulite severity. The surface morphology was quantified with a non-contact three-dimensional laser scanning system to generate surface roughness parameters and provide a standardized measure of severity. In the literature, cellulite severity is generally evaluated with various visual and photographic methods, although accepted standards have not yet emerged. We related the technical measures of severity to nai·ve and subject assessment using a 0-9 category scale. Quantitative, reproducible methods will facilitate effective comparison of treat­ ments across studies. Furthermore, treatment effectiveness will be judged by the patient/ consumer based on the impact on cellulite severity and appearance. Ultimately, evalu­ ation methods must be linked to human perception of severity and change. MATERIALS AND METHODS SUBJECTS Fifty-one females with visible cellulite were recruited from several weight-loss programs (medication, liquid diet, Weight Watchers®, and bariatric surgery). Eleven females without visible cellulite were controls. Individuals who were pregnant, had an active skin condition (e.g., rash, wound) on the thigh, or had been treated for cellulite within three months were excluded from participation. The Institutional Review Boards of Cincinnati Children's Hospital Medical Center and the University of Cincinnati ap­ proved the research protocol. All subjects provided written informed consent for par­ ticipation.

QUANTITATIVE MODEL OF CELLULITE 107 Ten males, matched to the female subjects for BMI and age, were recruited to determine the effect of gender on the morphological and biophysical characteristics of the thigh. All subjects provided written informed consent. The thigh areas were shaved with electric clippers prior to measurements. Sixty-two females without prior knowledge of the cellulite research were recruited as nai"ve judges from the general population. They evaluated the thigh images for severity, using a 0-9 category scale. The study subjects provided written consent for evaluation of their cellulite images. THREE-DIMENSIONAL SKIN SURFACE TOPOGRAPHY Three-dimensional (3D) skin surface data were obtained with a Cyberware Rapid 3D Digitizer (Cyberware, Inc., Monterrey, CA) laser scanner mounted on a linear platform and controlled by CyScan data acquisition software (Figure 1). The scanner operates on the principle of triangulation. As a helium-neon laser light source passes through two cylindrical lenses, the resulting vertical plane of light projects onto the surface of the object. The highlighted profile is reflected from the image mirrors to a video sensor and digitized in a raster fashion to determine the two-dimensional (2D) coordinates of 256 points along the profile surface. The scanner moves along a linear trajectory, performing El■ctranlc Dlgltlzar ECHO R■nga C■mara Calar C■m■ra Laser Light Source Auxiliary Light Source Figure 1. Three-dimensional laser-scanning process. The scanner operates on the principle of triangulation. As a helium-neon laser light source passes through two cylindrical lenses, the resulting vertical plane of light projects onto the surface of the object being scanned. The highlighted profile is reflected from the image mirrors to a video sensor and digitized in a raster fashion to determine the two-dimensional (2D) coordinates of 256 points along the profile surface. The scanner moves along a linear trajectory performing 512 individual surface contour scans in equal increments.