Sleep and mood disorders such as insomnia, jet lag, and seasonal affective disorder (SAD) affect many adults, and are related our sleep/wake cycle, also known as our circadian rhythm. According to a 2011 poll performed by the National Sleep Foundation, as many as 43% of Americans between the ages of 13 and 64 say that they rarely or never get a good night’s sleep on weeknights. In the United States, according to Mental Health America, SAD affects half a million people between the months of September and April. Light plays a fundamental role in the regulation of non-image forming (NIF) visual functions due to its effect on specialized photoreceptor cells in our eyes’ retina called intrinsically photosensitive retinal ganglion cells, or ipRGCs. Stimulation of ipRGCs by light affects the hypothalamus’ suprachiasmatic nucleus (SCN), which works like a clock that controls body temperature and regulates hormones such as cortisol, a stress-related hormone, and sleep-inducing melatonin.
Existing light box therapies for the treatment of SAD and sleep disorders can have a disruptive impact on conscious visual perception. Light therapies typically involve usage of very bright, wide-spectrum white lights. Until recently, spectral and dynamic tuning of light was uncommon due to the poor performance of lighting devices. With the emergence of light emitting diodes, new technologies for light therapy are now at our reach.
Pulsed LED therapy for the treatment of mood and sleep disorders
Researchers at the University of Michigan have used flickering LEDs to design a new light therapy device for the treatment of sleep disorders and SAD. By optimizing the intensity, flicker frequency, and duty cycle of the light emitted from the diodes, the device is able to stimulate subconscious vision without disturbing conscious visual perception. This protocol can be used to apply dynamic light therapy to a general environment and would prove useful in maximizing alertness in a workplace or school setting, as well as providing patients affected by SAD and other mood or sleep disturbances with an effective, non-invasive treatment that can be comfortably used at home.
- Low cost of treatment relative to traditional drug therapies.
- Non-invasive treatment has little effect on conscious visual perception.
- Treatment of jet lag, insomnia and mood disorders (SAD and depression).
- LED light therapy can also be used to treat skin conditions such as acne, and for cosmetic anti-aging effects.