Focal point technology: Controlling treatment depth and pattern of skin injury by a novel highly focused laser.

Background: Selective photothermolysis has limitations in efficacy and safety for dermal targets. We describe a novel concept using scanned focused laser microbeams for precise control of dermal depth and pattern of injury, using a 1550 nm laser that generates an array of conical thermal zones while minimizing injury to the epidermis.

Objective: To characterize the conical thermal zones in vivo and determine safe starting parameters to transition to a second phase to explore potential clinical indications.

Methods: A focused toroidal (ring) laser beam was delivered through a cold sapphire window, sparing epidermal injury in a central zone. Pulse energy, lesion depth, density, and energy delivery were titrated in ex vivo human skin and subsequently on the backs of 21 human subjects.

Results: Histology showed microscale patterns of thermal injury, which varied predictably with laser parameters. Time-course healing through histology and skin surface imaging demonstrated the ability of the device to deliver high energies without sequelae.

Limitations: Clinical data are currently being collected to further explore the safety and efficacy of the device.

Conclusion: The 1550 nm laser with focal point technology enables precise control of lesion depth while simultaneously sparing a large portion of the epidermis, lowering the risk of adverse effects.