INTERACTION OF THE LASER WITH HE BODY

Dr. Lorena Acevedo, resident in aesthetic medicine. University of Rosario, Bogotá, Colombia Updated by Adrian Rios, director of Unilaser Medical The laser, as a powerful and pure light, produces effects that exaggerate the reactions that light has with matter. There is an exchange of energy between light and our body. Visible light and objects communicate through specific waves, colors. Waves originate from charges. Everything that exists comes from forces that attract or repel each other and are balanced in the materials we can touch. Electrical charges are inherited from energy. Refraction , the phenomenon of distortion of the image of a pencil in a glass of water, is due to the fact that light takes longer to pass through water than through air, where there are not as many electrons to slow it down, while in water the greater number of these deflect it. When we see the surface of a lake from certain angles we see it as a mirror because more electrons are concentrated on the surface that return the light to the observer, we call this Reflection.

Image taken from: 4/9 Lake Bratan , The Pura Ulun Danu Bratan temple, dedicated to the goddess who inhabits this lake in the center of the island, stands on an islet surrounded by volcanic cones. MICHELE FALZONE / AWL IMAGES. https://www.nationalgeographic.com.es/viajes/grandes-reportajes/bali-la-isla-mas-bella_7541/4. Why do we see colors? Inside our eyes we have sensors to see three colors: blue, green and red, and we also have other types of sensors that measure the intensity of light. The brain processes color combinations. When we see the red color of a material that emits it, it will be absorbing the green and blue colors that are the colors we do not see.

The skin is a mixture of organic material, water and pigments. Water is transparent and this quality allows the passage of visible colour lasers, but when the laser is infrared in the medium and far ranges, it is captured by the water. When the laser is near infrared to visible light, the water in the skin allows this type of laser to pass through, while the pigments absorb it. The pigment’s basic condition is the absorption of waves and its function is to dissipate energy as a cushion that releases it in the form of heat. The absorption of the pigment is due to the fact that the electrons of the molecules receive the light in a quantum way, by selective strata. The presence in the molecule of groups with unshared electrons (-NH2, OH;-NO2;-COOR, among others) modifies the color and the intensity of the absorption characteristic of a chromophore group. Our natural skin pigment, melanin, blocks high-frequency light, ultraviolet light, from reaching DNA. The pigment converts ultraviolet light into infrared light.

Image taken from: http://myownlittlecloset.blogspot.com/2013/08/como-combinar-manipedi.html   The effect of lasers on tattoo ink is to exaggerate what is seen in makeup with antagonistic colors. Green lasers affect red ink. A green tattoo will not react much to a laser of the same color. Infrared lasers used in rejuvenation are basically invisible. They react against the water in the skin, accelerating the mobility of water molecules until they evaporate. Their effect on collagen is not direct, but is due to the heat conduction generated by the heating of the water. In addition, lasers in skin rejuvenation include the application of other lasers in the visible spectrum to treat spots. Lasers used to treat vascular skin lesions are absorbed by the blood pigment, hemoglobin, but can be retained by an abundant amount of melanin and this is why vascular lesions can only be treated when the skin is light or the lesions are very superficial. For many years, lasers for cutting skin have not been seen as useful and have been ignored by other equipment until a surgeon encounters crowded lesions in which management with common means is practically impossible and each action requires the least possible reaction. The laser in surgery only finds a place in surgeons who use the microscope as a fundamental tool. Skin rejuvenation with this type of laser has taught us how to treat this type of lesion. REFERENCES Dr. Marcel G. Clerc Gavilan. Department of Physics, Faculty of Physical and Mathematical Sciences. University of Chile. https://www.cec.uchile.cl/~mclerc/