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AN EXPERIMENTAL STUDY OF THE CHANGES IN PIGMENTATION IN HUMAN SKIN IN VIVO WITH VISIBLE AND NEAR INFRARED LIGHT
Author(s) -
Kollias N.,
Baqer A.
Publication year - 1984
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1984.tb03905.x
Subject(s) - irradiation , erythema , absorption (acoustics) , photochemistry , chemistry , infrared , visible spectrum , bundle , human skin , absorption spectroscopy , materials science , optics , optoelectronics , dermatology , biology , physics , medicine , nuclear physics , composite material , genetics
— The skin of the lower inner arm of volunteers was irradiated, with a 390–1700 nm light source, through a fiber optic bundle for times of up to 1.2 × 10 4 s and with powers of up to 0.35 W/cm 2 . Simultaneously with the irradiation, spectra (390–720 nm) of the remitted intensity were measured, while a 5.0 cm in diameter area of the skin around the fiber bundle was maintained at constant temperature, within 0.2°C. The generation of a photoproduct was observed and measured as changes in the remitted intensity within 600 s (10 min) of the start of irradiation. The photoproduct formed was characterized by a weak absorption in the blue part of the spectrum (400–450 nm), leading to a bluish appearance in the irradiated area only. The color change appears as a two step process. It starts with a “soluble” photoproduct, which disappears, within 24 h after irradiation, and an “insoluble” photoproduct which appears with irradiation greater than 3 ×10 3 s (50 min). No spectral differences were detected between the two photoproducts. The “insoluble” photoproduct persists for periods of up to 8 weeks. The color change in the skin is immediate and there is no erythema associated with this color change.