The effects of visible light, while common in the environment (visible spectrum accounts for 44% of total solar energy), remain undefined. An important safety feature of visible red light (600 nm to 700 nm) is that it does not generate pro-carcinogenic DNA damage as does ultraviolet (UV) light. Recently published clinical observations indicate that red light in combination with other modalities such as photosensitizers in combined red light photodynamic therapy can treat skin diseases. However, preliminary in vitro data generated by the investigator's research group suggests that red light can function as a stand-alone treatment, eliminating the side-effects of chemical photosensitizers and the potential long-term harm of current UV therapy. Furthermore, commercially available light emitting diode-red light (LED-RL) units exist and are already FDA-cleared for other dermatological uses (such as rhytides and acne), thus clinical translation for use in skin diseases could occur relatively quickly following safety and efficacy demonstration. Developing high fluence LED-RL phototherapy as a treatment for skin conditions may represent an important advance that lacks the serious systemic side effects associated with immunomodulatory agents (such as oral steroids); avoids the need for invasive, painful injections with anti-fibrotic agents (such as intralesional steroids, 5-fluorouracil and bleomycin); and eliminates the UV-induced DNA damage associated with skin cancer and photoaging that are associated with current UVA/UVA1 and UVB/narrowband UVB phototherapy. To the investigator research group's knowledge, no clinical trials have been performed to determine the safety of high fluence LED-RL in different Fitzpatrick skin types. The innovation of this approach is that the investigator research group intend to study the safety of high fluence LED-RL in Fitzpatrick skin types I to III (based on NIH's race/ethnicity category of non-Hispanic, Caucasian).~A previous study demonstrated that fluence up to 320 J/cm2 is safe for all skin types (unpublished data, investigator research group). This study will evaluate doses of 480 J/cm2 and 640 J/cm2 in Fitzpatrick skin types I to III. This is based on the classical method for dose escalation as described by Spilker: starting with dose (X) increased by an equal amount (in this instance: X=160 J/cm2 which is the maximum recommended starting dose in clinical studies, 2X=320 J/cm2, 3X=480 J/cm2, 4X=640 J/cm2).
The goal of this study is to establish the safety of high fluence LED-RL at fluence of 480 J/cm2 and 640 J/cm2 in healthy non-Hispanic, Caucasian subjects. The hypothesis is that high fluence LED-RL phototherapy is safe in non-Hispanic, Caucasians.