Nonablative Anti-Aging Light Therapy
Introduction: Nonablative Laser, LED, Intense Pulsed Light Therapy
Noninvasive skin rejuvenation treatments based on the use of nonablative lasers or intense light are becoming ever more popular, advanced and ubiquitous, especially with home use hand held devices. One of the key reasons is that they do not burn off the top layer of the skin (as opposed to ablative lasers), which means no or little downtime and lower risk of side effects and complications. Admittedly, for certain problems, such as moderate-to-deep wrinkles, nonablative laser and light treatments remain less effective than skin resurfacing with ablative lasers.
The principle behind all these methods is ‘selective photothermolysis’. In essence, a beam of light selectively targets and heats up and thereby damages a particular skin structure without damaging the surrounding tissue. Such targeted damage stimulates the healing response/process (skin remodeling/rejuvenation) without notable injury to the epidermis
Wavelength determines how deep a beam of light will penetrate the skin and what structures it will hit. Depending on the wavelength of the laser, LED or a narrow wavelength range of intense pulsed light, one can target stratum corneum, epidermis, upper or lower dermis. One can also specifically target blood vessels (e.g. to treat spider veins or rosacea), melanin (to treat pigmented lesions), collagen (to tighten skin) and so forth. For example, green light is absorbed by hemoglobin in red blood cells and causes targeted heating of blood vessels. Hence, it is used for targeted treatment of spider veins, facial flushing (in rosacea) and other vascular conditions.
Figure The visible region (450nm – 760nm)
Infrared
———— 760nm
Red
———— 630nm
Orange
———— 590nm
Yellow
———— 560nm
Green
———— 490nm
Blue
———— 450nm
Ultraviolet
Figure. Infrared Region
For our purpose “Anti-Aging”, the most commonly used wavelength is infrared or red laser, LED, or intense pulsed light. Visible red (620nm – 700nm) light shows at least 24 different positive changes at a cellular level. Visible red light, at a wavelength of 620 to 700nm (nanometers), penetrates human tissue to a depth of about 8-10 mm. Skin layers, because of their high blood and water content, easily absorb red light.
[CIE (International Commission on Illumination)’s division scheme for infrared is as follows:
- IR-A: 700 nm–1400 nm
- IR-B: 1400 nm–3000 nm
- IR-C: 3000 nm–1 mm
A commonly used sub-division scheme is:
- Near-infrared (NIR, IR-A DIN): 0.75-1.4 µm (750 nm -1400 nm)
- Short-wavelength infrared (SWIR, IR-B DIN): 1.4-3 µm
- Mid-wavelength infrared (MWIR, IR-C DIN) or intermediate infrared (IIR): 3-8 µm.
- Long-wavelength infrared (LWIR, IR-C DIN): 8–15 µm.
- Far infrared (FIR): 15-1,000 µm ]
Infrared (1100-1800 nm) allows it to penetrate relatively deeply – all the way to the lower dermis (the layer of skin where wrinkles reside) and make it useful for treating fine wrinkles and depressed scars. The infrared waves bypass the epidermis and are absorbed throughout the dermis, causing dermal heating. Such targeted dermal damage stimulates the response/process (skin remodeling/rejuvenation) without notable injury to the epidermis. The skin remodeling is reflected on the following changes: increased circulation and new capillary formation for oxygen and nutrients, stimulation of collagen production and activation of fibroblast (the cell make and secret the collagen), diminished hyperpigmentation or age spots by dissolving melanin, increased cellular energy ATP which in turn stimulating skin repair, lastly increased lymphatic system activity which helps the lymphatic system function more efficiently by facilitating toxin removal and improving skin circulation.
The difference between the light generated by lasers and non- laser photo devices is that lasers are synchronized light waves of one single wavelength with specificity and intensity. Conversely, non-laser photo devices (e.g intense pulsed light technology) emit a narrow spectrum of different wavelengths. Such devices often use special filters to remove unwanted wavelengths or to select a particular narrow range of wavelength for a particular target structure. Therefore, a single such system can be used to treat different skin conditions by using different filter. This makes non-laser photo devices (such as intense pulsed light systems) more versatile and more cost-effective. On the other hand, lasers remain superior when it comes to high specificity and precise targeting of the treatment.
Photodynamic therapy is the enhancement of the effects of commonly used lasers and light sources with photosensitizing agents. It is primarily used to treat other skin conditions. It has been used off-label for skin rejuvenation but is not approved by FDA for this indication.
Nonablative Anti-Aging Light Therapy
A variety of noninvasive rejuvenation treatments are based on the use of nonablative lasers, LED or intense pulsed light (IPL). These treatments are becoming ever more popular, advanced and ubiquitous. One of the key reasons is that they are less invasive than ablative laser skin resurfacing techniques which means no or little downtime and lower risk of side effects and complications although nonablative light treatments remain less effective than skin resurfacing with ablative lasers in treating moderate to deep wrinkles. All these methods are based on the principle of selective photothermolysis. In essence, a targeted beam of light selectively heats up and thereby damages a particular area of skin structure without damaging the surrounding tissue. Such targeted damage and the resulting healing response may produce cosmetic improvements, such as dissolution of spider veins and age spots, skin tightening, wrinkle reduction and so forth. ATP (or: adenosine triphosphate) is the fuel our skin cells use for repair and rejuvenation. Increased ATP allows a faster acceptance of nutrients in cells as well as better healing response, repair and rejuvenation. Research has shown that laser and light therapy can increase cellular ATP by as much as 150%, contributing to a better looking skin.
Wavelength determines how deep a beam of light will penetrate the skin and what structures it will hit. Depending on the wavelength of the laser, LED or a narrow wavelength range of intense pulsed light, one can target stratum corneum, epidermis, upper or lower dermis. One can also specifically target blood vessels (e.g. to treat spider veins or rosacea), melanin (to treat pigmented lesions), collagen (to tighten skin) and so forth. For example, green light is absorbed by hemoglobin in red blood cells and causes targeted heating of blood vessels. Hence, it is used for targeted treatment of spider veins, facial flushing (in rosacea) and other vascular conditions.
For our purpose “Anti-Aging”, the most commonly used wavelength is infrared or red laser, LED, or intense pulsed light (IPL). Longer wavelengths penetrate deeper into the target, longer wavelengths are used to treat deeper targets, and to avoid and protect superficial parts of the skin. Shorter wavelengths are used to treat more superficial targets and avoid damaging deeper skin parts. Visible red (620nm – 700nm) light shows at least 24 different positive changes at a cellular level. Visible red light, at a wavelength of 620 to 700nm (nanometers), penetrates human tissue to a depth of about 8-10 mm. Skin layers, because of their high blood and water content, easily absorb red light. Infrared (1100-1800 nm) allows it to penetrate relatively deeply – all the way to the lower dermis (the layer of skin where wrinkles reside) and make it useful for treating fine wrinkles and depressed scars. The infrared waves bypass the epidermis and are absorbed throughout the dermis, causing dermal heating. Such targeted dermal damage stimulates the response/process (skin remodeling/rejuvenation) without notable injury to the epidermis. The skin remodeling is reflected on the following changes: increased circulation and new capillary formation for oxygen and nutrients, stimulation of collagen production and activation of fibroblast (the cell make and secret the collagen), diminished hyperpigmentation or age spots by dissolving melanin, increased cellular energy ATP which in turn stimulating skin repair, lastly increased lymphatic system activity which helps the lymphatic system function more efficiently by facilitating toxin removal and improving skin circulation.
The difference between the light generated by lasers and non- laser photo devices is that lasers are synchronized light waves of one single wavelength with specificity and intensity. Conversely, non-laser photo devices (e.g. intense pulsed light technology) emit a narrow spectrum of different wavelengths. Such devices often use special filters to remove unwanted wavelengths or to select a particular narrow range of wavelength for a particular target structure. Therefore, a single such system can be used to treat different skin conditions by using different filter. This makes non-laser photo devices (such as intense pulsed light systems) more versatile and more cost-effective. On the other hand, lasers remain superior when it comes to high specificity and precise targeting of the treatment.
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