The implementation of lasers in the cosmetic arena dates back almost to the beginning of lasers themselves. In 1960, Dr. Theodore Maimen demonstrated the first working of a ruby laser. Within a few years, Dr. Leon Goldman, a dermatologist at the University of Cincinnati, demonstrated some early applications using a ruby laser on the skin [1]. The desire of dermatologists and other physicians to treat various conditions, stimulated more research and experimentation.
For the most part, lasers used in the areas of scientific research were modified or reengineered for use in the medical arena. Most notably, the argon (Ar) laser and the carbon dioxide (CO2) laser became the first lasers used for cosmetic procedures. The CO2 laser primarily ablates tissue, so for dermatologic procedures, most applications were used limited to “removing lumps, and bumps or warts.” Argon laser, with wavelengths of 488 nm (blue light) and 514 nm (green light) was the first laser to offer some selectivity for a specific chromophore (blood). Green light offered some reasonable absorption characteristics for blood, so doctors found that they could coagulate blood vessels quite effectively. However, because argon laser was a continuous wave laser, the heating of the blood vessels was usually excessive. For skilled users, argon laser was very effective, but for the majority of users and for the majority of applications, the argon laser required too much of technical know-how to be used on most patients. Other continuous wave or quasi-continuous wave lasers, (such as copper-vapor lasers and dye lasers) produced wavelengths that were more selective for chromophores such as blood (oxyhemoglobin) and pigmentation (melanin). For most part, they were more effective than the older argon technology, but they still lacked optimization regarding the target chromophores.
In the mid-1980s, Drs. Parrish and Anderson at Massachusetts General Hospital developed the theory of selective photothermolysis, which spurred the development of a class of medical devices that increased the selectivity of lasers and pulsed light sources for specific target chromophores [2]. Working within the confines of this theory, physicians, researchers, and corporate R&D staff were able to develop lasers and light sources that not only included wavelength selectivity, but also specific pulse durations and appropriate energies. In other words, laser manufacturers now designed systems that were better optimized to safely treat specific dermatologic conditions with the most appropriate lasers and light sources. From this point onward, lasers and light sources moved into a realm of safer and more effective systems, which provided increased patient satisfaction. Additional modifications of this theory have provided a broader basis for the development of other applications that had not even been thought of 10-20 years ago; so since the mid-1980s, the potential applications have broadened significantly to cover an extensive list of skin conditions.
This chapter will encompass the development and implementation of light-based technology in the cosmetic field. In this fast-moving market, continued research and development has yielded innovations in technology that have basically created new treatment opportunities that were unavailable only five years ago. Nearly every step of development has been spurred off from another older principle or technology. This chapter categorizes the discussion into four sections: coherent light-based systems, multiple wavelength intense pulsed light-based systems, nonablative and ablative fractional skin resurfacing, and fractional skin tightening. By tracing the path that technology has taken, we can understand better where it is at present, and where the research and development will take us in the future.