Table 1 Biophysical parameters and measurement equipment used and their selection of reference points.
(A) Descriptive Statistics | |||
|---|---|---|---|
Parameter category | Parameter name | Testing Equipment and Specifications | Testing Area |
Directly Collected by Instrument | Skin Moisture Content (CM) | Corneometer CM 825 (Courage + Khazaka, Germany) | Cheek |
Transepidermal Water Loss (TEWL) | Tewameter TM300 (Courage + Khazaka, Germany) | Cheek | |
Sebum Content (SM) | Sebumeter SM815 (Courage + Khazaka, Germany) | forehead, canthus, cheek, and jaw | |
Melanin (MEXA)/Eryth (ERYTH)MEXA/ERYTH | Mexameter MX18 (Courage + Khazaka, Germany) | Cheek | |
Skin Colour (ITA°)/Luminosity (L*)/Redness (a*)/Yellowness (b*)ITA°/b* | Colorimeter CL400 (Courage + Khazaka, Germany) | Cheek | |
Glossiness (GLOSS_DSC) | Skin-Glossymeter GL200 | Cheek | |
Skin Elasticity (R2/R5/R7) | Cutometer MPA580 (Courage + Khazaka, Germany) | Cheek | |
Skin Roughness (Ra/Rp/Rz) | VISIO 3D (DERMATOP V3, France) | Cheek | |
Current Perception Threshold (CPT2000 Hz/CPT250 Hz/CPT50 Hz) | NEUROMETER CPT/C (Neurotron, Germany) | Cheek | |
Blood Flow Perfusion | PeriScan PIM 3 (Perimed AB, Stockholm, Sweden) | Cheek | |
Skin pH | Skin pH-meter PH905 (Courage + Khazaka, Germany) | Cheek | |
Extracted by Imaging | Red Area/Spots: Surface average, Perimeter average, Occupation rate, Irregularity of edge, Spot AVG blue/green/red, SpotL, spotA, spotB, Spot AVG grayscale, Skin AVG blue/red/green/L/A/B, Skin AVG grayscale, Homogeneity Haralick | Extracted after obtaining standard facial images with Visia-CR | Entire face |
Brightness (Oily): Lightness, Specular Brightness Rate, Diffused Brightness Rate, Global Brightness Rate | |||
Wrinkles (Forehead/Glabellar/Crow’s Feet/Eye Fine Lines/Nasolabial Folds/Oral Furrows): Coefficient of visibility, Occupancy rate, Contrast wrinkles/skin | |||
Follicular orifices: Number, Area average, Area variance, Follicular orifice area/AOI area, Diameter average, Diameter variance | |||
Porphyrin Value (on the nose in the middle of the face) | |||
Acne: Number of different parts/different forms | |||
(B) Parameter Meanings and Descriptive Statistics of Oily Sensitive Skin Assessment Parameter Set. | |||
|---|---|---|---|
Parameter Dimension | Parameter Set | Parameter Meaning | X ± SD |
Moisture Level | Skin Moisture Content (CM) | The higher the CM value, the greater the skin moisture content. | 54.43 ± 15.21 |
Transepidermal Water Loss (TEWL) | TEWL values depend on the integrity of the stratum corneum and skin barrier function; higher values indicate more severe skin barrier damage. | 17.60 ± 6.58 | |
Sebum Content (SM) | The higher the SM value, the greater the sebum content. | 28.75 ± 21.54 | |
Colour Level | Melanin (MEXA) | The higher the MEXA/ERYTH value, the greater the skin melanin/haemoglobin content. | 147.33 ± 30.63 |
*Haemoglobin (ERYTH) | 280.52 ± 72.03 | ||
Skin Tone (ITA°) | The higher the ITA° value, the lighter and whiter the skin colour; the higher the L* value, the lighter the skin tone. The higher the a* value, the greater the redness. The higher the b* value, the greater the yellowness. | 55.35 ± 6.04 | |
Brightness (L*) | 66.36 ± 11.85 | ||
*Redness (a*) | 9.83 ± 1.51 | ||
Yellowness (b*) | 10.92 ± 2.22 | ||
Glossiness (GLOSS_DSC) | The higher the GLOSS_DSC value, the greater the skin glossiness. | 6.12 ± 1.27 | |
Brightness (Oily) Value: Specular Brightness Rate | The specular brightness rate represents the brightness of reflected light (oily) on the skin; a higher value indicates greater skin oiliness. | 0.003 ± 0.002 | |
Red Area: Surface average, Spot AVG grayscale, Homogeneity Haralick | Surface average represents the average area of redness/spots; Spot AVG grayscale represents the average grayscale value, determining the lightness/darkness of redness/spots; Homogeneity Haralick represents uniformity, with values closer to 1 indicating better uniformity of redness/spots within the selected area. | 2330.01 ± 796.42 | |
Red Area Brightness | 550.24 ± 38.71 | ||
Red Area Uniformity | 0.01 ± 0.004 | ||
Spot Area | 1012.13 ± 597.38 | ||
Spot Brightness | 280.08 ± 114.05 | ||
Spot Uniformity | 0.05 ± 0.08 | ||
Texture Level | Elasticity R2 | Total elasticity; the closer the value is to 1, the better the elasticity. R2 is the ratio of Ua (recoil without negative pressure) to Uf (maximum stretch with negative pressure), R5 is the ratio of Ur (elastic part of the skin recovery process during the first cycle of skin testing) to Ue (elastic part during negative pressure), R7 is the ratio of Ur to Uf during the first cycle of skin testing. | 0.73 ± 0.10 |
Elasticity R5 | 0.55 ± 0.14 | ||
Elasticity R7 | 0.35 ± 0.07 | ||
Roughness Ra | Arithmetic mean roughness, Ra, reflects the overall level of surface roughness; a higher value indicates greater roughness and more texture on the skin around the eyes; Roughness maximum height difference, Rp, reflects the degree of protrusions or depressions on the surface; a higher value indicates greater roughness and maximum height difference on the skin around the eyes; Roughness maximum peak-to-valley height difference, Rz, reflects the overall ups and downs of surface roughness; a higher value indicates greater roughness and maximum peak-to-valley depth difference on the skin around the eyes. | 0.0181 ± 0.006 | |
Roughness Rp | 0.14 ± 0.04557 | ||
Roughness Rz | 0.07 ± 0.02 | ||
Forehead Wrinkles Visibility | Coefficient visibility represents the visibility coefficient, indicating the number and density of wrinkles (density refers to the density of wrinkle grayscale levels); Occupancy rate is related to the area of wrinkles. | 15.50 ± 7.43 | |
Forehead Wrinkles Occupancy Rate | 0.96 ± 0.01 | ||
Glabellar Wrinkles Visibility | 12.22 ± 5.05 | ||
Glabellar Wrinkles Occupancy Rate | 0.90 ± 0.03 | ||
Crow’s Feet Visibility | 22.36 ± 5.37 | ||
Crow’s Feet Occupancy Rate | 0.93 ± 0.01 | ||
Fine Lines around Eyes Visibility | 14.42 ± 5.74 | ||
Fine Lines around Eyes Occupancy Rate | 0.92 ± 0.02 | ||
Nasolabial Folds Visibility | 15.15 ± 5.19 | ||
Nasolabial Folds Occupancy Rate | 0.91 ± 0.03 | ||
Oral Furrows Visibility | 28.06 ± 5.74 | ||
Oral Furrows Occupancy Rate | 0.94 ± 0.01 | ||
Follicular Orifice Count | The higher the follicular orifice count value, the more follicular orifices there are; Follicular orifice area/AOI area represents the proportion of follicular orifice area within the selected area. | 711.87 ± 74.72 | |
Follicular Orifice Area Ratio | 0.06 ± 0.01 | ||
Porphyrin: Porphyrin Value (on the nose in the middle of the face) | Porphyrin is a secretion of Citibacterium acnes, which resides in hair follicles and causes acne. Porphyrin can fluoresce under ultraviolet light, appearing as round white spots, and its distribution on the face can reflect the content of Citibacterium acnes on the face to some extent. | ||
Acne: Number of different parts/different forms | Categorized and counted according to different facial areas, totalling 7 areas: forehead, temples, glabella, nose, left cheek, right cheek, and jaw; Categorized and counted according to different forms of acne, divided into two types with a total of 8 indicators: (a) ① early development, ② about to burst, ③ ruptured, (b) ① whitehead, ② papule, ③ pustule, ④ nodule, ⑤ cyst. | ||
Perception Level | Current Perception Threshold (CPT2000 Hz) | The lower the CPT value at each frequency, the lower the sensory threshold of the skin nerves, and the higher the skin’s neural sensitivity: 2000 Hz - Aβ fibres: conduct vibration sense, pressure (touch, pressure sense); 250 Hz - Aδ fibres: conduct pressure, temperature (cold), fast pain, and mechanical stimulation sensation; 5 Hz - C fibres: conduct nociceptive sensation, slow pain, temperature (burning) sensation. | 89.04 ± 39.01 |
Current Perception Threshold (CPT250 Hz) | 16.64 ± 11.50 | ||
Current Perception Threshold (CPT5 Hz) | 9.74 ± 8.70 | ||
Skin pH - Cheek | Above 7 is alkaline, below 7 is acidic, and 7 is neutral. Healthy Eastern skin pH should be between 4.5 and 6.5, that is, slightly acidic. | 6.01 ± 0.40 | |
Skin pH - Forehead | 5.92 ± 0.49 | ||
Skin pH - Jaw | 5.90 ± 0.42 | ||
(C) Selection Reference Points for Biophysical Parameters | |||
|---|---|---|---|
Main Type (N) | Subtype (N) | Description and Data Pattern | |
Oily Skin (65) | Oily and Water-Deficient (51) | High sebum secretion, low moisture content. | |
SM (top 33%), CM (bottom 33%). | |||
SM > 31.5, CM < 49.76 | |||
Oily and Well-Hydrated (14) | High sebum, moderate moisture content. | ||
SM (top 33%), CM (top 66%). | |||
SM > 31.5, CM > 49.76 | |||
Dry Skin (53) | Dry and Fat-Deficient (32) | Low sebum secretion, low moisture content. | |
SM (bottom 33%), CM (bottom 33%). | |||
SM < 17.5, CM < 49.76 | |||
Dry and Well-Fatigued (21) | Moderate sebum, low moisture content. | ||
SM (between 33-66%), CM (bottom 33%). | |||
17.5 < SM < 31.5, CM < 49.76 | |||
Neutral Skin (82) | Neutral Skin (82) | Moderate sebum, moderate moisture content. | |
SM (bottom 66%), CM (top 66%). | |||
SM < 31.5, CM > 49.76 | |||
Sensitive Skin (63) | Barrier Sensitive (19) | Weak skin barrier function, i.e., high pH and TEWL. | |
pH (top 33%), TEWL (top 33%). | |||
pH > 6.2, TEWL > 18.71 | |||
Neurosensitive (15) | High neural sensitivity, i.e., low CPT values at three frequencies. | ||
CPT (2500 Hz, 250 Hz, 50 Hz) (top 33%). | |||
CPT2000HZ < 105, CPT250HZ < 19, CPT5HZ < 13 | |||
Inflammatory Sensitive (44) | High vascular and inflammatory responses, i.e., high haemoglobin content, a* value, and red area. | ||
Haemoglobin content (top 33%), a* (top 33%), Red area (top 33%). | |||
Haemoglobin content > 308.33, a*>10.41, Red area > 2496.26 | |||
Nonsensitive Skin (137) | Nonbarrier Sensitive (181) | Does not meet the criteria for barrier sensitivity | |
Non-Neurosensitive (185) | Does not meet the criteria for neurosensitivity | ||
Non-Inflammatory Sensitive (156) | Does not meet the criteria for inflammatory sensitivity | ||
