In vivo characterization of the threshold of laser‐induced optical breakdown (LIOB) of a fractional 1064 nm Nd:YAG picosecond laser by optical coherence tomography: A step forward to precision laser therapy

Clinical endpoints serve as an important guide to physicians during laser treatment. However, there are no reliable clinical endpoints for the fractional picosecond laser-induced optical breakdown (LIOB) whose threshold is dependent on the irradiance of the laser and epidermal melanin content of the skin treated.To determine the LIOB threshold in vivo of a 1064nm fractional picosecond laser for different skin colors.A cellular-level resolution optical coherence tomography (OCT) has successfully demonstrated that the in vivo morphological change of LIOB in the epidermis by a fractional picosecond laser. By measuring the melanin content in the area of the skin to treat using a skin imaging device, the physician would therefore be able to determine the threshold of LIOB visually under OCT for the skin of that particular melanin content.The pilot study has demonstrated that OCT may serve as a non-invasive modality to determine the thresholds of LIOB by a fractional picosecond laser. And the established correlation between melanin content and LIOB threshold in this pilot study may further guide physicians, that is, physicians may be able to predict the threshold of LIOB, without having to see the clinical endpoints, by simple measurement of melanin content of the skin to treat preoperatively.