The purpose of this study was to determine the effect of visible light on the immediate pigmentation and delayed tanning of melanocompetent skin; the results were compared with those induced by long-wavelength UVA (UVA1). Two electromagnetic radiation sources were used to irradiate the lower back of 20 volunteers with skin types IV-VI: UVA1 (340-400 nm) and visible light (400-700 nm). Pigmentation was assessed by visual examination, digital photography with a cross-polarized filter, and diffused reflectance spectroscopy at 7 time points over a 2-week period. Confocal microscopy and skin biopsies for histopathological examination using different stains were carried out. Irradiation was also carried out on skin type II. Results showed that although both UVA1 and visible light can induce pigmentation in skin types IV-VI, pigmentation induced by visible light was darker and more sustained. No pigmentation was observed in skin type II. The quality and quantity of pigment induced by visible light and UVA1 were different. These findings have potential implications on the management of photoaggravated pigmentary disorders, the proper use of sunscreens, and the treatment of depigmented lesions.

Electromagnetic radiation has vast and diverse effects on human skin. Although photobiologic studies of sunlight date back to Sir Isaac Newton in 1671, most available studies focus on the UV radiation part of the spectrum. The effects of visible light and infrared radiation have not been, until recently, clearly elucidated. The goal of this review is to highlight the effects of visible light on the skin. As a result of advances in the understanding of skin optics, and comprehensive studies regarding the absorption spectrum of endogenous and exogenous skin chromophores, various biologic effects have been shown to be exerted by visible light radiation including erythema, pigmentation, thermal damage and free radical production. It has also been shown that visible light can induce indirect DNA damage through the generation of reactive oxygen species. Furthermore, a number of photodermatoses have an action spectrum in the visible light range, even though most of the currently available sunscreens offer, if any, weak protection against visible light. Conversely, because of its cutaneous biologic effects, visible light is used for the treatment of a variety of skin diseases and esthetic conditions in the form of lasers, intense pulsed light and photodynamic therapy.

The long-pulse Nd:YAG laser is effective for treatment of HS. The effectiveness of Nd:YAG laser, a hair epilation device, supports the primary follicular pathogenesis of the condition.

These data support the use of NAFL as a highly effective treatment modality for surgical scars, with greater improvement in scar appearance than with PDL. It is likely that the greater depth of penetration and focal microthermal zones of injury with NAFL, inducing neocollagenesis and collagenolysis, account for its greater improvement in scar remodeling. These encouraging results lead us to recommend that NAFL be added to the current treatment armamentarium for surgical scars.

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Paradoxical hypertrichosis is a rare side effect of laser hair removal; the pathogenesis of this event remains widely unknown. We recommend further large-scale studies to investigate this effect. The authors have indicated no significant interest with commercial supporters.

Fractional photothermolysis is effective for the treatment of acne scars, but practition-ers should be aware of the higher incidence of pain and postinflammatory hyperpigmentation in individuals with skin types IV to VI.

The cure rate remains the most important consideration in choosing the treatment method, but additional factors, such as the patient's general medical condition, psychosocial circumstances, the location of the tumor and cost effectiveness of the therapy should be considered. Mohs micrographic surgery remains the preferred treatment for high-risk tumors and tumors located in cosmetically sensitive areas.