LASER
PHOTOTHERAPY
Treatment with light is a very attractive method for modifying the skin: the potential for trauma, allergies, systemic effects and adverse reactions is much less than with other modalities. Modern treatment systems can deliver specified intensities and wavelengths of light in specified times to achieve the desired results.
The system with which I am most familiar, Cutera(R), produces light with a laser and with flash lamps.
Laser is a unique form of light of a single wavelength which is in phase and collimated, that is to say, the beam does not spread out over any short distance. The result is that the energy of the light is deposited in a very limited area of the skin, so that the resulting heat is tightly focused. This allows for the heat to be directed to a specific structure, such as a "broken" blood vessel, which is cauterized and eventually absorbed. It can also be used to deliver heat to the hair shaft in a hair follicle, cauterizing the follicle so that it ceases to produce a hair. In these cases, it is the visible color of the chromophore which absorbs the light, focusing the heal on the structure to be cauterized; the light passes through the overlying skin and underlying tissues without producing much heat. For this reason, this type of treatment is ineffective for removing white hair.
The laser can also be used for a type of treatment which is not restricted to chromophores. In this method, pulses of laser light are applied in a random manner to an entire area of skin, by the thousands. Each pulse heats a very small area, resulting basically in a burn which is too small to cause any scarring, or even blistering, but initiates a healing process which smoothes the skin and reduces the size of the pores. This is effective for scarred, uneven, wrinkled and "coarse" skin, and especially for acne. Some of the effect is immediately evident, but as the skin heals over the following month even more of the cosmetic improvement becomes visible.
One of the flash lamp systems is used to treat unwanted pigment, particularly freckles, age spots, birthmarks, and the dark "mask" sometimes resulting from pregnancy or hormones. The flash lamp cools the surface of the skin while it delivers a very brief burst of intense light which heats the pigment without burning the skin. The heat initiates an inflammation in the pigment which causes the pigment to be sloughed off over the next couple of weeks: the spots eventually peel off, leaving the skin clear with no scarring. The darkest spots are the first to respond, so that it may be necessary to retreat the lighter spots later. Larger pigmented areas, such as the "mask" and "port wine stains" are more difficult to remove completely, and may require ongoing treatment with bleaching creams for the best results.
The other flash lamp system delivers a slower pulse of light and heat while cooling the surface. Rather than being absorbed by pigment, the heat is absorbed by the water in the deeper layers of the skin, causing the skin to visibly tighten, smoothing out wrinkles and reversing laxity and sagging. Once again, some of the effect is immediately visible, but the results increase over the healing period. The result can be much the same as a facelift, but without any cutting, injections, bruising, scarring or "down time".
In order to obtain the best results from these treatments, consideration must be given to the causes of the underlying problems, such as poor diet, hormones, inadequate hygiene, tobacco use or sun exposure. Attention to these issues may greatly improve the amount and duration of the improved appearance.
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