Scientific report on how blue light causes severe retinal lesion – Could f.lux be to some use?



  • In 05 July 2018 the report “Blue light excited retinal intercepts cellular signalling” was published at Nature/Scientific Reports.
    It was also given attention in an article at The Universe of Toledo (US): “UT chemists discover how blue light speeds blindness”.

    According to the report there is undeniably more than circadian sleeping disorders (which are severe enough) to consider when it comes to handle blue light.

    It would be interesting to hear what the opinions here have to say in this important matter.


  • f.lux team

    Blue Light Hazard is the main reason that we get solar retinopathy--it's real, and staring at the sun too long will lead to photoreceptor damage. But that is really bright light.

    The problem is that everyone, including this article's PR department, is confusing the dose of indoor lights and screens with actual hazard levels. Screens make 100x less energy than spending time outdoors when you're not staring at the sun. And thousands of times less than these harmful doses, which are more like "staring at the sun for an hour".

    DOSE is what matters, and so, if the dose of a computer display is enough to cause these effects, f.lux would be pretty helpful to use in avoiding them. But it's important to say that the dose is likely too low: hours of computer use gives you less blue light exposure than minutes of time outdoors.

    The one complication is that the retina is somewhat more sensitive at night, and we don't know if the retina is more sensitive to harm then.

    We do know the dose from a computer screen is in the range required to affect the body's circadian rhythms (and likely the retinal rhythms too). But with retinal hazards, we can't measure even the tiniest bit of risk based on any of the usual methods.



  • Very interesting about the dose factor and the comparative indoor/screen vs outdoor figures. The report, as far as I’ve read it, doesn’t mention any such comparisons. On the other hand the report is presenting somewhat new methods in how to look at/measure this area. I’m not sure how much that effects the findings, and if there, in the certain aspects the report is looking at, could be some difference in blue light coming from screens and the blue outdoor sunlight light that is mixed with and a part of the whole sunlight spectra.
    Anyway, I would very much appreciate a link to some of the sources were the comparative figures mentioned above comes from.
    When it comes to blue screen light and effects on circadian body (sleeping) rhythm there is no doubt. It’s well documented. And also my one experience. That’s how I come to use f.lux, and have continued to do so.


  • f.lux team

    The main reports are ICNIRP and IEC62471 - they define a blue light hazard spectrum. The landmark papers include Ham 1976. Before that we didn't know that "blue light" would be the most sensitive part of the spectrum for a retina.

    Ratnayake did not measure irradiance--that is, they measured total power from a laser, but then the press compared the power in this tiny laser dot as if it had been spread out over a square centimeter. This is just not the same thing! A tiny dot at this power level damages retinal tissue and when it's spread out so it's 10,000x dimmer, it does not.

    This looks like a good summary:
    https://www.aaopt.org/docs/2018/2018-handouts/go/v1__ses_go-05.pdf