Valkee light therapy in-ear device lacking in evidence

The manufacturer Valkee has recently released an in-ear product to ease symptoms associated with seasonal affective disorder (SAD). The product is a similar size and shape to an MP3 player with earphones designed to beam light directly into the ear. Valkee claim that when used for 8-12 minutes a day, 5 days a week for 4 weeks the product can ease depressive symptoms. Due to the novel concept of delivering light therapy through the ear (and not the eyes) the Valkee product has received coverage in newspapers and online. The manufacturer claims that the success of the in-ear product is due to the brain’s ability to react to light. I decided to ask for evidence for this claim.

I first looked for evidence on the Valkee website. I tried to find out if Valkee’s research used randomised trials, control groups, and whether it was peer reviewed. The current evidence from Valkee supporting the in-ear product does not follow these standards. For example, one study concluded that "92% of winter blues sufferers experienced total symptom relief with 8-12 minutes of Valkee daily" but this study did not include a control group who should have received no light therapy or a placebo. Another claim that the "human brain is sensitive to light, not just our eyes" was based on a study using cadavers, and has not yet been published in a peer reviewed journal. Good quality evidence supporting the Valkee in-ear product, for the purpose of easing symptoms associated with SAD, is still not available.