Disparity in Cutaneous Pigmentary Response to LED vs Halogen Incandescent Visible Light: Results from a Single Center, Investigational Clinical Trial Determining a Minimal Pigmentary Visible Light Dose
November 2017 | Volume 16 | Issue 11 | Original Article | 1105 | Copyright © 2017
Teo Soleymani MD,a David E. Cohen MD MPH,b Lorcan M. Folan PhD,c Uchenna R. Okereke MD,b Nada Elbuluk MD MSc,b and Nicholas A. Soter MDb
aDepartment of Dermatology, Stanford University School of Medicine, Redwood City, CA bThe Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, NY cThe Tandon School of Engineering, New York University, New York, NY
Background: While most of the attention regarding skin pigmentation has focused on the effects of ultraviolet radiation, the cutaneous effects of visible light (400 to 700nm) are rarely reported. Objective: The purpose of this study was to investigate the cutaneous pigmentary response to pure visible light irradiation, examine the difference in response to different sources of visible light irradiation, and determine a minimal pigmentary dose of visible light irradiation in melanocompetent subjects with Fitzpatrick skin type III - VI. Methods: The study was designed as a single arm, non-blinded, split-side dual intervention study in which subjects underwent visible light irradiation using LED and halogen incandescent light sources delivered at a fluence of 0.14 Watts/cm2 with incremental dose progression from 20 J/cm2 to 320 J/cm2. Pigmentation was assessed by clinical examination, cross-polarized digital photography, and analytic colorimetry. Results: Immediate, dose-responsive pigment darkening was seen with LED light exposure in 80% of subjects, beginning at 60 Joules. No pigmentary changes were seen with halogen incandescent light exposure at any dose in any subject. Conclusion: This study is the first to report a distinct difference in cutaneous pigmentary response to different sources of visible light, and the first to demonstrate cutaneous pigment darkening from visible LED light exposure. Our findings raise the concern that our increasing daily artificial light surroundings may have clandestine effects on skin biology.
J Drugs Dermatol. 2017;16(11):1105-1110.
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The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation and is arranged based on wavelength, from shortest to longest. The visible portion of the electromagnetic spectrum is defined as the portion of electromagnetic radiation visible to the human eye, which corresponds to wavelengths from 400 to 700 nanometers (nm).1,2 The impact of UV radiation on skin pigmentation has been well-established and its association with cutaneous disease, which range from aging and chronic actinic photo-damage to both non-melanoma and melanoma carcinogenesis, has been described in the literature.2-8 While most of the attention with respect to skin darkening is focused on the effect of the UV region of the solar spectrum, the effect of visible radiation has received little attention. However, solar radiation reaching the earth’s surface contains 12 to 14 times more visible radiation than UV.6 This study investigated the effects of two different sources of visible light, light emitting diode (LED) and halogen incandescent, on the cutaneous pigmentary response in individuals with Fitzpatrick skin types III-VI.
While most of the attention regarding skin pigmentation has focused on the effects of ultraviolet radiation, the cutaneous effects of visible light (400 to 700nm) are rarely reported. The purpose of this study was to 1) investigate the cutaneous pigmentary response to pure visible light irradiation, 2) examine the difference in response to different sources of visible light irradiation, and 3) determine a minimal pigmentary dose of visible light irradiation in melanocompetent subjects with Fitzpatrick skin type III - VI.
MATERIALS AND METHODS
The study was reviewed and approved by the Institutional Review Board at New York University School of Medicine. Study procedures were followed in accordance with the ethical standards of the Institutional Review Board and the principles of the Helsinki Declaration of 1975. Informed consent was obtained from all participants before initiation of the study.
To be included in the study, volunteers had to be at least 18