Professor Zhang Dechun tells you how laser scar removal works.
Thermal Effect
High-power lasers possess high energy and can generate intense heat, which is destructive to tissues. Depending on the irradiation dosage, it can cause erythema, blisters, coagulation, carbonization, vaporization, etc., in tissues. In medicine, focused lasers are made into "light knives" for cutting tissues, with advantages such as neat and clean incisions, minimal bleeding, clear vision, and precise treatment areas.
The effect of lasers on human tissues mainly depends on the parameters of the laser and the physiological characteristics of the tissue. Generally speaking, lasers in the infrared and red light range have significant thermal effects; lasers in the blue, purple, and ultraviolet light ranges have relatively stronger thermal effects. Tissue's ability to absorb lasers is mainly related to its inherent properties, water content, and pigmentation. Tissues with more pigmentation have a strong absorption capacity for lasers, produce more heat, and are easily damaged, while tissues with less pigmentation are the opposite.
Some tissues or substances have a strong absorption capacity for certain types of lasers. For example, the cornea and lens of the eye are more sensitive to infrared and ultraviolet lasers; melanin has the highest absorption peak at 500-600nm in the spectrum, hemoglobin has absorption peaks at 420nm, 532nm, and 577nm in the spectrum; argon ion lasers and frequency-doubled neodymium glass lasers with wavelengths similar to these can be used for selective treatment of pigmented skin diseases and vascular diseases.
Scars are divided into keloids, (inflammatory) hypertrophic scars, superficial scars, contracture scars, atrophic scars, and depressed scars, etc. Burns in daily life generally cause severe scars such as hypertrophic scars, contracture scars, and keloids, while surgery can lead to hypertrophic scars, depressed scars, and keloids. Depressed scars are commonly seen after acne, pimples, smallpox, and chickenpox. Therefore, different causes can lead to different types of scars, and the same cause can also result in scars of varying degrees and types due to individual physical differences.