INTRODUCTION
Photoepilation is one of the top five non-invasive medaesthetic procedures performed in the United States, with over 800,000 procedures performed in 2014 alone.1 The technique has become an attractive long-term solution for both hirsutism and hypertrichosis, as well as for normally distributed but unwanted hair growth. It is most widely exploited by Caucasian (73.2%) and female (87.1%) patients within the 35-50-year-old age group (44.9%).1 Photoepilation is founded upon pulsed delivery of light energy to hair follicles, where it is efficiently absorbed by melanin of the residing stem cells and dermal papilla. The inherent optical and thermal properties of the pigmented cells enable selective photothermolysis of the hair and its follicle, with permanent damage to the follicular epithelium and consequential disruption of hair growth.3 At the same time, overlying skin and proximal cells or tissues are spared, due to their lower optical absorption at the deployed wavelength with the appropriate pulse width.Maximal treatment selectivity is secured by laser hair removal devices combining wavelengths selectively absorbed by melanin (700-1200 nm), pulse durations equal to or shorter than the thermal relaxation time of the follicle and high peak power. However, darker skin phototypes with high epidermal melanin concentrations, compete with the targeted hairs and absorb laser energy, which can lead to thermal skin damage18 and reduced therapeutic efficacy. Devices using longer wavelengths of light provide for reduced scatter and deeper light penetration, most advantageous for skin types with high epidermal melanin concentrations,14,19 but require higher fluence to compensate for the reduced thermal effect within the follicle. Overall, these lasers have demonstrated particular clinical relevance in darker skin phototypes but generally require multiple treatment sessions to obtain satisfactory results.4,8,14,16In addition to the aforementioned tunable optical parameters, spot size inversely correlates with dermal scattering, where larger spot sizes are associated with deeper penetration and a consequential reduction in fluence demands.9 Thus, when designed in conjunction with a large spot size, long-wavelength lasers reduce the epidermal-to-follicular energy absorption ratios, rendering them particularly suitable for dark-skinned patients.The LightSheer Infinity with the HS handpiece (Lumenis Ltd.), designed for delivery of fluences of up to 14 J/cm2 over a 22x35 mm area, is equipped with a vacuum chamber, which