A Quantitative, Cross-Sectional and Observational Study to Characterize Age-Related Structural Changes in Facial Skin of Chinese Women Using Line-Field Confocal Optical Coherence Tomography (LC-OCT)

1. Chinese female, aged between 20 and 70 years (inclusive) at the time of signing consent.
2. Willing and able to provide written informed consent.
3. Fitzpatrick Skin Phototype II or III.
4. Willing to comply with all study procedures, including removal of facial makeup and avoidance of intensive skincare (e.g., retinoids, strong acids) on the test areas for 3 days prior to the visit as per instructions.

Exclusion Criteria:

1. Pregnant, planning pregnancy, or breastfeeding (as hormonal changes significantly affect skin properties).
2. Presence of temporary tanning, sunburn, or significant erythema on the face or measurement areas.
3. Presence of facial piercings, tattoos, too much fluff or significant scarring that would interfere with imaging or measurements in the areas of interest.
4. History of any aesthetic or surgical procedure on the face (e.g., laser therapy, chemical peels, injectable fillers, botulinum toxin, plastic surgery) within the past 12 months.
5. Current diagnosis or visible signs of a skin disease (e.g., psoriasis, eczema, active acne, rosacea) or a systemic disease known to affect the skin (e.g., diabetes, lupus) on the face or measurement areas.
6. Use of systemic medications known to affect skin physiology (e.g., oral retinoids, immunosuppressants, long-term corticosteroids) within the past 3 months, or for a cumulative duration of ≥6 months within the past 2 years.
7. Participation in another clinical study on the face or arms within the past 1 month.