15.6.1 Laser and Intense Pulsed Light
The usage of light as a form of phototherapy for the treatment of fine lines and wrinkles has seen extensive growth and usage amongst nonablative instrumentation. As noted earlier, the ability of controlled wavelengths of light to impact skin biology and structure is attained by selective stimulation of wound-repair processes in the underlying dermis while sparing the epidermis from any significant damage, particularly compromising the stratum corneum and barrier. The wavelengths and fluencies that have been studied, reported on, and commercialized are fairly broad, and this chapter will focus upon the major ones, including nonablative lasers, intense pulsed light (IPL) and light emitting diodes (LED).
In contrast to usage of lasers for ablative facial skin resurfacing, lasers and IPL for nonablative procedures is based on using longer wavelengths in the mid-infrared range (i. e., 1300-1600 nm) that can penetrate deep into the dermis of skin without compromising the barrier or damaging a precooled epidermis. Some of the lasers that have been studied and used in the field include the 1540 nm erbium, 1450 nm diode, and 1320 Nd:YAG. Numerous published reports have shown that there are significantly noticeable treatment effects upon fine lines and wrinkles from various regimens of treatments. Some of the earliest published work reported findings that using a nonablative laser could lead to significant improvements in fine lines and wrinkles [44], and that long – term treatment can lead to increased efficacy [45]. Amongst an Asian patient base, it was reported that as few as three treatments over a two-month period were found to have satisfactory effects on diminishing fine lines and wrinkles [46]. A direct comparison between long-pulse laser and IPL showed that both were able to positively improve fine lines and wrinkles, but that the long-pulse laser had fewer negative side effects [47]. This is also consistent with IPL having a weaker effect on fine lines and wrinkles compared to long-pulsed lasers. In general, IPL has a more robust effect upon pigmentation endpoints in contrast to structural alterations associated with fine lines and wrinkles. In addition, laser treatments have been reported to last as long as two years, including the fact that treated patients responded better to follow-up treatment than nontreated patients [48]. While some of the side effects from nonablative lasers and IPL include transient erythema and postinflammatory hyperpigmentation, these are significantly less than that from ablative techniques. Overall, it has been reported that patient satisfaction is relatively high from these techniques [49].