Blue Light

Technically speaking, Blue Light is not a laser, but a light-based skin therapy operating on a slightly different principle from laser.  One way to explain the distinction is that laser delivers light as coherent, highly directional beams, while the Blue Light delivers ‘incoherent’ light scattered over a larger area.  A ‘bright side’ to this difference is that Blue Light causes no disturbance to the surface skin, either sensate or visible; treatment is completely comfortable (even soothing and therapeutic) and requires no recovery time.
Blue Light has proven very effective at controlling the bacteria that causes acne and is gaining increasing popularity for this purpose.  As a safe, non-ablative light, it has no side-effects (as other acne treatments or drugs often do), causes no pain, and is capable of controlling the condition for long periods of time.  The usual course of Blue Light acne treatment requires several short sessions scheduled at intervals determined by the doctor, until the Blue Light clears the sebaceous glands of the acne-causing bacteria and the surface skin heals.
Blue Light is also an effective anti-aging tool capable of reducing photodamage on the skin, including sun damage, age spots, and fine lines and wrinkles. If used for this purpose, Blue Light is often used with Levulan, a photosensitizing drug that is applied topically prior to the Blue Light session, as described:

Blue Light with Levulan

Levulan is a topical photosensitizing drug that increases the intensity of the Blue Light effect.  It is sometimes uses for acne treatment or anti-aging Blue Light.  In either case the Levulan Kerastick is applied to the skin about an hour before the Blue Light session.  It is given time to be fully absorbed, and then is activated by the light.  Blue Light with Levulan leaves the skin especially sensitive to UV light, so extreme care with sun protection is necessary after the procedure.