Clinical efficacy of intradermal type I collagen injections in treating skin photoaging in patients from high-altitude areas

Figure 2 Facial photographs and associated redness feature maps of four participants. The images illustrate the condition of the face before treatment, after the third treatment, and after the sixth treatment. Notably, red zone counts decreased after each treatment compared with baseline. A: A 52-year-old female patient. The redness feature maps show a clear reduction in facial redness from before treatment to after the 3^rd and 6^th treatments; B: A 49-year-old female patient. Similar to patient A, the redness feature maps demonstrate a progressive decrease in facial redness following the 3^rd and 6^th treatment sessions compared to baseline; C: A 46-year-old female patient. The redness feature maps reveal a noticeable decline in facial redness after the 3rd treatment, with further improvement seen after the 6^th treatment; D: A 51-year-old male patient. Consistent with the female patients, the male patient's redness feature maps illustrate a gradual reduction in facial redness from before treatment to following the 3^rd and 6^th treatment sessions.