If you are not familiar with cosmetic laser surgery, you will be amazed that nowadays these lasers are used to correct a myriad of symptoms associated with the aging skin, including vascular lesions, reticular veins, skin laxity, wrinkles, sun spots, melanomas, and many others. The question that you are likely to ask is “how does a laser correct all these symptoms?” To understand what I have to explain, you need to learn something about the principle that lasers operate and the way they act on the skin.
Unlike a light bulb, a laser is a narrow, highly focused, and extremely intense beam of light with unique qualities. The color of light emitted by a laser is determined by the substance (medium) that lies within the laser’s inner chamber. Lasers are usually named after the solid, liquid, or gas substance which is used to generate the beam of light. For example, if the medium is solid ruby crystal, as in the case of a ruby laser, red light is emitted.
Each laser emits a single wavelength of light. The wavelength of a laser beam is directly responsible for its color; two lasers that emit the same wavelength of light will always emit the same color. There are also lasers used for cosmetic purposes that do not produce colored beams. The wavelengths of these lasers are in the infrared region (wavelength longer than red light, 700 nm to 3000 nm), which the human eye cannot see.
Each laser light, characterized by its wavelength, represents a key designed to open only one lock. Wavelength determines which component of the skin (melanin, hemoglobin) will absorb the radiation and how far into the skin the light will penetrate. The ideal laser to affect a given target is the one maximally absorbed by that target. For example, a red substance like hemoglobin, which reflects red light, will maximally absorb green light. Accordingly, a green laser beam will selectively target the hemoglobin found in the skin. The other physical properties of cosmetic lasers that determine their effectiveness are power and pulse duration. These determine how much laser energy is imparted to the skin.
To be useful, a laser used in cosmetic laser surgery must be able to remove or destroy the unwanted skin component without altering or damaging the overall structure of the skin. When strategically selected and combined, the three variables (wavelength, power, and pulse duration) of a laser machine will provide a remarkable degree of precision in targeting a specific skin component and therefore produce the best result.
