There’s much discussion about how the use of electric lighting in buildings can support the body’s circadian system. The exposure to daylight, the quality and quantity of electric lighting, and task-appropriate illumination levels are thought to help improve energy, mood and productivity.
The concept has been around for a long time, but the research and applicability to our commercial industry are somewhat in their infancy. We don’t actually know everything about the way light stimulates our circadian system to truly replicate all the natural processes that follow night and day, nor do we know whether that would actually be desirable in all cases. Yet, light fixture manufacturers have powered onward, some more carefully than others.
In the early 2000’s, it was discovered that certain cells in our eyes, called ipRGCs (Intrinsically Photosensitive Retinal Ganglion Cells), can stimulate our circadian process in the presence of light. One of these ipRGC’s has a maximum sensitivity at a particular wavelength – 490nm to be exact. A lot of manufacturers jumped on the bandwagon and started advertising lighting for health, or circadian lighting, all focused on this one particular discovery. But in the past year we’ve discovered that it’s only the tip of the iceberg. There are actually five of these ipRGCs, but there is research on only one of them so far. This is all very exciting for the lighting industry, and the medical community is also very interested. But we’re still all trying to better understand it.