Several reports have been published over the last two decades describing the successful removal of benign cutaneous pigmented lesions such as
lentigines, café au lait macules'
nevi,
nevus of Ota, and
lentigo maligna by a variety of
lasers such as the excimer (351 nm),
argon (488,514 nm), ruby (694 nm), Nd:YAG (1060 nm), and CO2 (10,600 nm).
Laser treatment has been applied to lesions with a range of pigment depths from superficial
lentigines in the epidermis to the
nevus of Ota in the reticular dermis. Widely divergent
laser parameters of wavelength, pulse duration, energy density, and spotsizes have been used, but the
laser parameters used to treat this range of lesions have been arbitrary, with little effort focused on defining optimal
laser parameters for removal of each type. In this study, miniature black pig skin was exposed to five wavelengths (504, 590, 694, 720, and 750 nm) covering the absorption spectrum of
melanin. At each wavelength, a range of energy densities was examined. Skin biopsies taken from
laser-exposed sites were examined histologically in an attempt to establish whether optimal
laser parameters exist for destroying pigment cells in skin. Of the five wavelengths examined, 504 nm produced the most pigment specific injury; this specificity being maintained even at the highest energy density of 7.0 J/cm2. Thus, for the destruction of
melanin-containing cells in the epidermal compartment, 504 nm wavelength appears optimal.