TITLE:
Protection from Near-Infrared to Prevent Skin Damage
AUTHORS:
Yohei Tanaka, Lisa Gale
KEYWORDS:
Near-Infrared, Protection, Skin Damage, Ultraviolet
JOURNAL NAME:
Optics and Photonics Journal,
Vol.5 No.4,
March
31,
2015
ABSTRACT: Over half
of the solar energy consists of near-infrared, and in addition to natural
near-infrared, humans are increasingly exposed to artificial near-infrared from
electrical appliances. Thus, we are exposed to tremendous amounts of
near-infrared. Despite the wide prevalence of a variety of ultraviolet blocking materials, the necessity
to protect against near-infrared has not been well recognized. To clarify the
necessity to protect against near-infrared, we assessed cell
viability of human fibroblast cells after
water-filtered broad-spectrum near-infrared (1100 - 1800 nm together with a
water-filter that excludes wavelengths 1400 - 1500 nm) treatment using 2 sets
of transparent polycarbonate plates, one to block ultraviolet and
the other to block both ultraviolet and near-infrared. The cell viability was significantly decreased
after 10 rounds of near-infrared irradiation at 20 J/cm2 in
near-infrared treated cells without a protective polycarbonate plate and near-infrared treated
cells using the polycarbonate plate to block only ultraviolet.
Assuming that the cell viability of the non-irradiated control to be 100, the
cell viability of the
near-infrared treated cells without any protection was 0.2.
The cell viability of
the near-infrared treated cells with the polycarbonate plate to block only
ultraviolet was 0.3, whereas both ultraviolet and near-infrared protected cells retained a viability
of 85.1. The
results of this study indicate that protection from not only ultraviolet but
also near-infrared should be
considered to prevent skin damage.