Monday 11 November 2019

Reason and the blues

I had a bit to say about blue light in my executive summary of Karolina Zielinska-Dabkowska's work on spectral impact on the retina and the visual cortex. She is concerned that the displacement of  trad incandescent lamps by compact fluorescent lamps CFLs is having unconsidered consequences on human health and happiness. CFLs are better for the planet's carbon footprint, but their spectrum is really different from that of natural sunlight especially in the evening. This seems to interfere with blue-sensitive intrinsically photosensitive retinal ganglion cells - ipRGCs to play havoc with your sleep-wake cycle.

All that science, all that evidence, is a bit overwhelming for Joe and Josie Public. In imitation of the simple politics of Animal Farm “Four legs good, two legs bad” people have been bamboozled into accepting and repeating a "blue light bad" mantra. Entrepreneurs, ever restless for new markets to exploit, started to manufacture and sell blue filters for screens, these seems to be software based rather than transparent foils to remove blue.

But here's Phillip Yuhas, the Professor of Optometry at Ohio State U, givimg us some advice about screen-eye coordination for health; invoking the 20-20-20 rule. Every 20 minutes, take 20 seconds to focus on something 20 feet [6m] away it will make your eye-muscles work and not get lazy. Also blink early and blink often - 10-12 times a minute will keep the optics lubricated, Old people take note: homeostasis on maintaining trickle in the tear ducts is not as good as it once was.

Yuhas also sets us straight on what matters . . . and its not blue filters. It's picked up on JSTOR too. They are only capable of reducing blue wavelengths by about 15%, which is equivalent to holding your screen 3cm further from your cornea. Try that now? See any diff? No, so you can take the blue filter off your Christmas list.

He still agrees with Karolina Zielinska-Dabkowska (and the evidence) about the impact of blue light from CFLs and screens on your ipRGCs with adverse effect on your sleep hygiene. But a tech fix is not called for here. It's a self-discipline issue. Getting enough quality sleep is important! It's worth working to achieve. We live in a world with infinite time choice. IF the BBC schedules a must see programme just before your bedtime THEN you can catch it later in the week. And face it, all the crud we watch, how much of that is vital to our health, wealth or happiness. The hours I spend watching trees being felled and Mongolian throat singers for edutainment = mostly of no value. Really I'd be better off sacking out on the sofa following Winnie-the-Pooh [Not!]: Sometimes I sets and thinks, and sometimes I just sets in preparation for bed.

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