Patients will receive one laser treatment (week 0) with the Erbium YAG laser at a 2940nm wavelength (Alma - Harmony XL Laser) and parameters corresponding with their acne scar severity. They will then return to the clinic 1, 4 and 8 weeks (7, 30, and 56 days + 7 days) after the treatment for their scars to be evaluated under optical coherence tomography.

Laser parameters are as follows:

iPixelEr 2940nm Erbium:YAG Module: mild scars: 7 by 7 (7X7) mm tip, energy 1400-1600 millijoules/P (mJ), pulse energy 5 Hz, 2-6 stacks, pulse mode L, 2-3 passes, 10% overlap moderate scars: 7X7 mm tip, energy 1600-1800 mJ/P, pulse energy 5 Hz, 2-6 stacks, pulse mode L, 2-3 passes, 10% overlap severe scars: 7X7 mm tip, 1800-2000 mJ/P, pulse energy 5 Hz, 2-6 stacks, pulse mode L, 2-3 passes, 10% overlap

The Erbium YAG laser at a 2940nm wavelength is used for ablative laser resurfacing as well as treating acne scars.

Optical coherence tomography (OCT) will be used to quantitatively measure changes in facial atrophic acne scars in terms of blood flow (proportion of signals with strong dynamic signal (%)/depth (mm)).

Optical coherence tomography (OCT) will be used to quantitatively measure changes in facial atrophic acne scars in terms of epidermal thickness (mm).

OCT will be used to qualitatively measure changes in facial atrophic acne scars in terms of collagen content. Collagen content will be measured in terms of brightness of OCT scan. Areas of skin that contain collagen tend to be brighter (more white in color) whereas areas with less collagen content tend to be darker.

OCT will be used to quantitatively measure changes in facial atrophic acne scars in terms of skin roughness (µm).

Scale (1-10) used to qualitatively monitor treatment and changes in scars by the patient.

Scale (1-10) used to qualitatively monitor treatment and changes in scars by the dermatologist.