First attempt by a lighting manufacturer to warn customers about the wrong light at the wrong time and its biological disruptions. http://edition.cnn.com/2015/06/09/health/light-bulb-warning

The article says thus "The packing on every one of their products will carry a "Notice" that "exposure to certain electric lights may cause biological effects, some potentially disruptive." Underneath the message is a website that will provide education material that spells out the potential negative health effects of artificial light."

The website features articles about the impact of light on circadian rhythms and sleep.

"Scientists have talked about this for years, but now a lighting company is about to point that out to every single one of its customers. And they are doing it voluntarily. What's the catch?" asks the article.

This seems to be an oversimplification of the issue.

We have around 120 million rods and 6 million cones in the retina. Cones are densely packed in the center area called the fovea and the rods are distributed around the retina and completely absent in the center.

When light hits the rods, they switch off, triggering a neurotransmitter relay which stops the melatonin production. Melatonin is the sleep hormone which is derived from Serotonin which is supposed to be the happiness hormone.

Considering the following data from one of the sleep friendly bulbs from the website, with 800 lumens at 2500K color temperature (warm tone), we see that it can provide more than 50 lux to 100 lux near the bedside or on the walls of the room.

Most rods switch off beyond 1 to 5 lux and up to 30 to 40 lux a combination of rods and cones work and beyond 50 lux, only cones work. (multiply foot candles by 10 to get lux, 5.21fc is around 50 lux). Check one of my previous posts for more details on rods and cones.  http://archinect.com/lightingdesign/chapter-1-a-brief-history-of-you

Even if the bulb provides a warm tone of light, if it provides lighting levels which switch off rods, it will eventually disrupt melatonin secretion and hence our sleep. We need darkness to convert serotonin to melatonin.

To quote an example from my book (http://www.amazon.com/dp/B00TKSLSK4), the first set of pictures A and A1, shows the typical bulb with 400 lumens in a lamp shade near bedside providing bright light patches beyond 30 lux on the room surfaces and above 100 lux by the bedside. Ceiling (Sky) is covered with 30 lux of light. Our eyes would see it as daytime.

FIG - A and A1 

FIG - B and B1

By using a low intensity warm color LED strip on the underside of the bed, higher lighting levels are restricted to the underside of bed and on the vertical surfaces in our visual fields, lighting levels are lower than 2 lux. Ceiling (Sky) is literally dark. Our eyes would see it as night time.

With less than 2 lux in our visual field, more rods will be ON, triggering a melatonin secretion response which will result in a sound sleep.

Circadian rhythm is a completely different aspect involving melanopsin in ipRGC (intrinsically photosensitive Photo Ganglion Cells).

Receptive fields of our ganglion cells, respond to variations in intensity, wavelength, timing, pattern and light history in our environment. It is more of a contrast meter than a light meter. 

The healthy lighting design proposed in my book (fig B and B1) addresses the intensity (<2 lux), wavelength (warm color, not, tone), timing (late evening), pattern (no pattern! makes you sleep), light history (Early morning, daytime, early evening layers before this layer) to ensure an optimum Circadian rhythm.

And to address healthy sleep and circadian rhythm by changing to a warm tone lamp is a huge oversimplification.

I am reminded of an article http://www.technologyreview.com/view/427907/path-dependence-and-the-stupidity-of-led-light-bulbs/ by Christoper mims, questioning the cramming of a 21st century technology in to a socket designed by Edison in the 19th Century. He called it the path dependence. Can you believe that they had a hybrid bulb which can work on gas and electricity with electric wires close to a gas pipe?

The warning label strategy on a bulb, takes it to a new level by trying to masquerade a 19th century design approach as a healthy alternative of the 21st century.

What do you think? Share your comments below.

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I aim to spread awareness on the subject of Healthy Lighting designs to facilitate co-creation of healthy lighting at home, work and other social spaces. My posts can be accessed at Archinect  and Linkedin Group. I also have a self published book "Healthy Lighting of your Homes" at Amazon.