This presentation was delivered during the LightSymposium 2016 in Wismar, Germany. Duration: 53:05 min.
Abstract: Light is an indispensable tool for beauticians and anti-aging experts. Shortly after the development of the incandescent lamp electrical light baths became available for addressing intended uses in the realm of wellness, beauty and restoration. In the middle of the 20th century the sales of cosmetic and therapeutic heat lamps turned into a mainstream business. Three decades later, soft lasers and LEDs for Low Level Light Therapy (LLLT) and photobiomodulation (PBM) entered the stage. Today, various light sources and technologies are available for wound healing, tissue regeneration and photorejuvenation of the skin.
Could it be valuable for a lighting professional, regardless if designer or engineer, to occupy his mind with pondering over results and effects of light applications in the field of beauty and anti-aging treatments? Definitely yes! Even if light for vision purposes is produced exclusively for the eye, it will, as a side effect, also illuminate skin areas which are not covered by garments. Skin and eyes have some properties in common, both are light perception organs (Wunsch 2006). What light can do to the skin on the cellular level it can also do to the eye and vice versa. If the beautician uses blue light for damaging germs in the skin via the induction of reactive oxygen species (ROS), the lighting professional should know about this capability: HEV (high energy visible = short wavelength) light can damage skin and eye via an identical process (Zastrow et al., 2009). Light with long wavelengths is able to help the skin to regenerate and it fosters repair and wound healing (Hamblin & Demidova, 2006). This should be taken into account in the risk assessment of non-thermal light sources with regard to ocular health, because they exhibit a lack of these beneficial red and near-infrared wavelengths. Cosmetic and therapeutic light applications can elucidate the potential of light to influence biological functions of skin and eye.
II. Light for skin rejuvenation
Photon emitters, such as lasers or LEDs, have proven to be effective light sources for PBM during re- cent decades, thereby demonstrating that it is not the technical type of light source but the treatment parameters such as wavelength, irradiance, and fluence that are likely to be accountable for the effects. However, laser and LED light sources may offer some disadvantages because of their punctiform emission characteristics and narrow spectral bandwidths. Because the action spectra for tissue regeneration and repair consist of more than one single wavelength, it might be favorable to apply a polychromatic spectrum covering a broader spectral region for skin rejuvenation and skin repair. We investigated the safety and efficacy of two different novel non-thermal, non-ablative, atraumatic, polychromatic low-level light treatment modalities with a focus on pleasant skin feeling, improved skin appearance, intradermal collagen increase, and the visible reduction of fine lines and wrinkles in a prospective, randomized, controlled trial that consisted of 136 volunteers (Wunsch & Matuschka, 2014).
III. Results and conclusions
The treated subjects experienced significantly improved skin complexion and skin feeling, profilometrically assessed skin roughness, and ultrasonographically measured collagen density. The blinded clinical evaluation of photographs confirmed significant improvement in the intervention groups compared with the control. Efficacy could be demonstrated for both polychromatic light sources with differing spectra. Both novel light sources that have not been previously used for PBM have demonstrated efficacy and safety for skin rejuvenation and intradermal collagen increase when compared with controls. Low level red and near infrared radiation can contribute to positive effects in human skin in vivo and therefore should be implemented in the assessment of light-tissue interactions not only in the cosmetic and medical field, but also in the field of general lighting applications due to the significantly longer exposure times.
 Wunsch, A. (2006). Human light response via skin, eye and brain. In CIE (Ed.), CIE X: Proceedings of the 2nd CIE expert symposium on lighting and health: 7 – 8 September 2006, Lord Elgin Hotel, Ottawa, Ontario, Canada (pp. 200-203).
 Zastrow, L. et al. (2009). The missing link–light-induced (280-1,600 nm) free radical formation in human skin. Skin Pharmacol Physiol, 22(1), 31-44.
 Hamblin, M. R., & Demidova, T. N. (2006). Mechanisms of low level light therapy. Proc SPIE, 6140, 1-12.
 Wunsch, A., & Matuschka, K. (2014). A controlled trial to determine the efficacy of red and near-infrared light treatment in patient satisfaction, reduction of fine lines, wrinkles, skin roughness, and intradermal collagen density increase. Photomed Laser Surg.