Lasers Surg Med. 2008 Jul;40(5):293-9.
Long-pulsed dye laser versus intense pulsed light for photodamaged skin: a randomized split-face trial with blinded response evaluation.
Jørgensen GF, Hedelund L, Haedersdal M.
Department of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
In this paper, Gitte Jørgensen reports a rarely seen type of study in the aesthetic space – a randomied comparison of two competing device technologies. The study was co-sponsored by both device manufacturers, but neither manufacturer participated in the conduct or analysis of the study. Most aesthetic device studies compare a device treatment to an untreated control, to show that the treatment causes some effect. In contrast, this study compared the Candela VBeam Perfecta (long pulse 595nm dye laser) with the Ellipse Flex (Intense Pulsed Light) for the treatment of photodamaged skin, to see if the treatments caused different outcomes
The study was well-designed to demonstrate the differences with each type of treatment. First, the patient population was homogenous (light skin females). Reduction of patient variability reduces confounding of outcomes and enables smaller sample sizes. Second, each study participant received a series of 3 split-face treatments with the one side randomized to each device type, which properly controls for non-study effects (e.g. additional sun exposure). The use of the series of 3 treatments would magnify outcome differences, if there were any. Third, the evaluation was performed on-site by a blinded, independent physician, to prevent bias and to prevent the introduction of photographic artifact. Although blinding adequately prevents bias, agreement from multiple blinded observers would be useful to reduce individual subjectivity in the assessment of improvement.
While both devices demonstrated improved outcomes in this study, the long pulse 595nm dye laser achieved overall superior results, due to superior performance on vascular lesions. Fourteen of 20 patients obtained better clearing of telangiectasias with the pulsed dye laser and the remainder saw no difference. The difference in lightening was both statistically and clinically significant (i.e. the difference in lightening was visually apparent to the blinded reviewer and the patient). Both devices achieved similar improvements for irregular pigmentation and skin texture. Neither device showed any improvement in wrinkles/rhytids. Eighteen of 20 patients preferred the pulsed dye laser, both because of improved vascular clearance and because there was less treatment-related pain.
Despite an excellent study design, there are some limitations to the study conclusions. The superior results of the pulse dye laser should not be considered definitive, as there was no-pre-defined study hypothesis to be proven. The study was too small to determine whether there was a significant difference in the rates of adverse effects between the two devices. Because both devices demonstrated improvement in outcomes, practitioners may be able to achieve pulsed-dye-laser results by simply performing additional IPL treatments. Possibly, other IPL systems may perform better than the Ellipse product used in this study.