Exploring the Thermal Dynamics of Laser Light on Human Skin

Abstract Laser light has garnered significant attention in both the medical field and modern cosmetic dermatology. However, lasertissue interactions can cause skin damage due to undesired hyperthermia. This study investigated the thermal dynamics of laser light on human skin layer using a 1D simplified bioheat model of Gagge’s. Two energy levels were selected 20 mj/cm2 of wavelength 660 nm, and 30 mj/cm2 of 805 nm. The pulse width was fixed at 10 ns, and the exposure time was set at 10 sec. Each energy level was explored under five pulse repetition rates (10, 20, 30, 50 and 100 Hz), three skin types (type II, III and V), two gender types (male and female), and three age groups (young adults 30 yrs., older adults 50 yrs., and elderly 80 yrs.). Results showed that hyperthermia was induced at pulse repetition rates greater than 30 Hz, for all skin types, gender and age groups. Young adults were most likely to experience hyperthermia with the shortest duration being 2 sec for energy level II at 100 Hz. People with skin type V are most susceptible to hyperthermia compared to skin type II and III. This difference was more significant at Energy level I. The findings of this study are of significant interest for minimizing laser-induced thermal damage to the skin while still achieving the desired treatment outcomes.