Since man began to understand the mechanisms of natural and biological processes, he has tried to artificially mimic them for his better enjoyment. This is the case, for example, with the development of cosmetics and products made from natural botanical extracts or even with the use of a vaccine. The vaccine is nothing more than a presentation of a foreign molecule to our body so that it recognizes, reacts, and is prepared when it actually encounters the microorganism that possesses it.
With solar radiation, responsible for maintaining life on Earth, it is no different. In addition to its importance for the production of oxygen by photosynthesizing beings, the beneficial mechanisms of light on biological tissues have also been artificially harnessed. We can cite the use of blue light for the treatment of jaundice (yellow pigmentation caused by excess bilirubins in the skin of newborns) as well as infrared light for physiotherapy.
Aesthetic and dermatological treatments became possible starting in the 1960s with the development of lasers. However, there is a variety of techniques and forms of energy use. Depending on the power applied to an area over a certain period of time, the biological mechanisms activated are distinct, as are their results.
Thus, we can basically divide light treatment methods into ablative and non-ablative methods. Ablative methods are highly invasive and cause removal of both the epidermal and dermal layers, inducing their remodeling (DeHoratius et al, 2007). This procedure improves firmness, roughness, and wrinkles of the facial skin as well as reducing spots; however, it can have serious side effects such as infections, inflammations, and scars (DeHoratius et al, 2007).
Non-ablative methods appear as a milder treatment alternative, and their way of acting on tissues is distinct, being used for the treatment of malignant tumors, acne, tissue regeneration, and pain relief, as well as dental treatments (DeHoratius et al, 2007). But it is important to emphasize that often these treatments are complementary to conventional treatments, such as chemotherapy and cancer surgeries (Atilli et al, 2011).
The devices used for rejuvenation by non-ablative methods can also be categorized into: infrared lasers; photodynamic therapy (PDT); light-emitting diodes (LED) based on the mechanisms of action of low-intensity light therapy. Below, we will break down each of them a bit to understand their functions.
Some wavelengths of infrared lasers heat the tissue and stimulate collagen production, improving fine wrinkles. For PDT, a photosensitizing agent is necessary, which will be modified by light, producing molecules that can induce cell death, thus being used in the treatment of malignant tumors and acne. LEDs are home-use devices that can even help relieve pain. Their mechanism is based on photochemical modification, when a molecule present in our tissues modulates protein synthesis. However, the protocols used in clinical studies are still quite varied, as are the techniques where these radiations are employed, currently making it impossible to reach a consensus on the understanding of the still controversial mechanisms of action of these devices on the skin.
Unfortunately, we do not have enough lines to address all the varieties of treatments and protocols that have been published by the scientific community. Thus, just as these techniques can be beneficial, they can also be harmful if powers or even wavelengths are used inappropriately. Therefore, read, inform yourselves, always research in scientific forums, and seek competent professionals before making any decisions.
References
Attili SK, Ibbotson SH, Fleming C. Role of non-surgical therapies in the management of periocular basal cell carcinoma and squamous intra-epidermal carcinoma: a case series and review of the literature. Photodermatol Photoimmunol Photomed. 2012 Apr;28(2):68-79
DeHoratius DM, Dover JS. Nonablative tissue remodeling and photorejuvenation. Clin Dermatol. 2007 Sep-Oct;25(5):474-9. Review. PubMed PMID: 17870525.
