Laser skin resurfacing using a frequency-doubled Nd:YAG laser after topical application of an exogenous chromophore

Laser skin resurfacing is usually performed with CO2 or Er:YAG lasers. Since frequency doubled Nd:YAG laser (532 nm) is already used in dermatology for angiodysplasias treatment, a new laser resurfacing method was investigated. In this study, we evaluated the possibility to achieve skin resurfacing using a 532 nm laser after topical application of an exogenous chromophore. This exogenous chromophore consisted in carbon dispersed and mixed with film-forming polymers and water. The resultant solution was applied to the skin surface using an air brush. Validation was performed in vivo on rat skin using the following laser parameters (532 nm, 2.7 W, 1 mm, 50 - 200 ms). Skin biopsies were taken to evaluate histological changes and to quantify epidermis ablation and dermis coagulation. Wound healing was followed up. The results showed that dermis coagulation depth increased as a function of exposure time. In conclusion, the concept of applying a carbon-based solution onto skin in order to obtain firstly laser light conversion into heat and secondly an heat transfer to the tissue is valid for laser skin resurfacing. By selecting exposure time, dermis coagulation depth can be either the one observed with Er:YAG laser or the one obtained with CO2 laser.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.