INTRODUCTION
Most of the signs we associate with skin aging including: fine lines and wrinkles, enlarged pores, pigmentary alterations, skin sagging, and redness, are due to long-term sun-exposure and not chronological aging.1-3 This is easily demonstrated by comparing sun-exposed facial skin to areas where the sun doesn’t shine, on the same individual. The sun turns on genes in the skin that result in abnormal distribution of epidermal pigmentation, as well as causing the normal collagen-rich dermis, with its fine meshwork of elastic fibers, to be digested away and replaced with large, non-functional clumps of abnormal elastic tissue called solar elastosis.1-3 Almost a quarter century ago it was discovered that creating a wound with a high-powered carbon dioxide (CO2) laser results in skin remodeling and replacement of solar elastosis with dermis that has a more normal architecture.4 This in-turn, reduces the signs of photodamage. However, full face CO2 laser treatments also resulted in significant down-time, and were sometimes associated with side-effects of infection and scarring.5 These early lasers gave way to fractionated CO2 lasers, which treated small areas of skin while leaving zones of intervening untreated skin.6 Side-effects and downtime were significantly reduced with fractionated treatments. Further developments in laser technologies in other industries led to medical lasers incorporating infrared fiber lasers, which were non-ablative or minimally ablative, further reducing side effects, but often requiring a series of treatments for optimal outcomes.7-9 Q-switched lasers designed for tattoo and pigmented lesion removal were also developed to deliver fractionated microbeams for facial rejuvenation.10-11 Further advances in tattoo-removing lasers led to the development of picosecond-domain lasers with sub-nanosecond pulses.12-14 These lasers have been fitted with various optics to create fractionated arrays of high-fluence treatment zones of picosecond-domain pulses, and have been used to treat photodamage and acne scarring with little or no downtime.15-21 The shorter sub-nanosecond laser pulses combined with focusing of the beam allows the delivery of high-intensity pulses sufficient to induce optical breakdown in tissue at lower energies compared to nanosecond laser pulses, thus enabling the high intensity pulses to be delivered with minimal disruption to tissue.22
MATERIALS AND METHODS
Subjects
Healthy male and female subjects between the ages of 18 and 75 with Fitzpatrick skin types I-VI, and mild to moderate facial, perioral and/or periorbital rhytides, who were willing to undergo laser treatments, were eligible for this IRB-approved study. Exclusion criteria included: pregnancy and breastfeeding,
