Assessing Plantar Skin Epidermal Layer in Response to Various Insole Hardness via Deep Learning Enabled Optical Coherence Tomography Analysis.

We tested walking interventions using adjustable air-insoles with hardness values of 80, 160, and 240 mmHg over walking durations of 10 and 20 min. Optical coherence tomography (OCT) was used to measure the thickness of the stratum corneum (SC) and living epidermis (ED) in three different locations: the big toe (T1), first metatarsal head (M1), and second metatarsal head (M2), and deep learning was used to compare the difference in thickness between SC and ED. The results indicate that SC thickness increases in M1 is statistically significant after 20 min walking interventions using 80 mmHg insole hardness, and SC thickness decreases in T1 and M1 are statistically significant after 20 min walking using 160 mmHg insole hardness. Changes in SC and ED thickness observed in this study highlight their potential relevance in evaluating plantar tissue health in the context of DFU prevention.