Dermatol Surg. 2009 Feb;35(2):229-39.
In the eye of the beholder–skin rejuvenation using a light-emitting diode photomodulation device
Boulos PR, Kelley JM, Falcão MF, Tremblay JF, Davis RB, Hatton MP, Rubin PA
Review copyright 2009 https://aestheticdevicereview.wordpress.com
In an unusual article, Boulos and colleagues present compelling evidence that the GentleWaves LED device simply does not work, and that patient satisfaction is simply the result of a placebo effect.
In this study, 36 patients were treated with the GentleWaves device weekly for 8 weeks, as suggested by several other researchers. Standardized photography was performed pre-treatment, immediately post-treatment, and 1 month post-treatment. The unblinded investigator also performed clinical assessments at the same time points.
Thirty raters were asked to select the “after” photo from a randomly ordered before/after pair, looking at one of five aspects of the treatment – redness, wrinkles, dark spots, skin roughness, and general appearance. Unfortunately, the results were not different from chance.
The data were re-evaluated by using a consensus of three raters for each aspect. Still, the results were no different from chance.
Next, statistical power was increased by using raters’ confidence in their own judgements to weight the data. In other words, this analysis more highly weighted the decisions that the raters felt sure about, and underweighted the decisions where the raters felt unsure. Nevertheless, results again were not different from chance.
Finally, the unblinded investigator’s clinical assessments showed that “there was essentially no effect, or if anything, a negative effect.”
Despite the lack of any objective evidence of improvement whatsoever, patients were quite pleased with the results. The authors conclude that the treatment is a classic placebo, where patients feel better because they believe that the treatment will work, even though it does nothing. At AestheticDeviceReview, we would like to see more devices subjected to this type of study.