• Chemists discover how blue light speeds blindness
    43 replies, posted
I'm aware that it's not literally blue light in that it's illuminated that colour, but the photons entering our eyes are blue, otherwise we wouldn't perceive the sky as blue at all.
ya but I think the key here is intensity, artificial blue light is quite intense compared to our normal scattering of daylight, especially in certain climates. Not to say that the sun itself isn't dangerously bright though.
The sky is much brighter than your average monitor. You can test that with any camera.
https://www.youtube.com/watch?v=BinWA0EenDY So I'm guessing this dude is pretty fucking blind by now
Garry was ahead of his time.
Why Isco everything I like terrible? I can't even have a favorite color without finding out it's trying to cripple me!
This paper is kind of silly. They only looked at the effects of free retinal, but retinal is never found in this form under physiological conditions, precisely because it is reactive and toxic. Retinoids circulate in the form of all-trans-retinol bound to a transport protein [ref 1, ref 2]. In photoreceptors, 11-cis-retinal is bound to opsins via an imine linkage. Absorption of a photon induces isomerisation to all-trans-retinal, causing a series of conformational changes that initiate signal transduction. The imine linkage is then hydrolysed to release free all-trans-retinal, which is quickly reduced to all-trans-retinol by various photoreceptor retinol dehydrogenases [ref 3], a step that is essential to avoid light-induced degeneration of photoreceptor cells [ref 4]. all-trans-Retinol is shuttled to retinal pigment epithelium (RPE) cells, where it undergoes a series of enzymatic reactions to regenerate 11-cis-retinal, after which it is transported back to photoreceptor cells and incorporated into apo-opsins to regenerate active opsins. Even this movement across the tiny gap between RPE cells and photoreceptor cells requires a transport protein, interphotoreceptor retinoid-binding protein (IRBP) [ref 5]. The authors exposed isolated HeLa cells to free all-trans-retinal and observed signs of oxidative stress. Specifically, the results they obtained suggest that phosphatidylinositol-4,5-bisphosphate (PIP2) is oxidised by reactive oxygen species (ROS) generated from photoexcitation of retinal. PIP2 is normally localised in the plasma membrane, but they hypothesise that oxidised PIP2 is solubilised and thus enters the cytoplasm, where it initiates signalling cascades via the phosphatidylinositol-4,5-bisphosphate head. Although they didn't characterise possible oxidation products of PIP2, I'm willing to let that pass as it is plausible. However HeLa cells are not equipped with enzymes of the visual cycle and are unable to process all-trans-retinal for recycling into 11-cis-retinal. It's really not surprising that treating them with retinal then exposing them to light results in oxidative damage. I don't question their results, but I'm very doubtful of their physiological relevance.
Knowing that natural white light also contains blue light (and some light that is even more energetic)... How bad could it be?
I just changed my f.lux settings to "candle" aka the darkest setting on the app to be on at all times of the day. It's 12am and i gotta say it feels better already
f.lux author here, still slogging through the article. It is hard to understand the light levels used because they use "power" (uW, mW) from a laser, and not "irradiance" (uW/cm^2 or mW/cm^2), so which area they have concentrated that light over is hard to understand. All I can see is it is from a laser, so the irradiance could be extremely high. The human lens filters most light at the peak of the given spectrum for free retinal (383nm), and so once you get to 450nm like an LED, the hazard data in the visual range is 100x less sensitive, see Fig 1 here: https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1751-1097.... It bears repeating that computer screens have <5% the hazard-weighted irradiance of a blue sky. (Can't make a direct comparison with lasers.) Not sure the conversion to white light is correct, and it is unclear to me right now if this much retinal is available in vivo.
Ha, jokes on you, I'm colour blind.
Built into windows 10 now (Night Light) and it doesn't mess with FreeSync and other things.
UV Radiation: Its Impact on the Human Eye. ... Fortunately we have the cornea (front of the eye) and the lens in the eye which absorb UV light and reduce the amount of UV rays reaching the retina (the back of the eye). Source: Vision There are also x-rays and gamma rays, but too few to bother us in normal circumstances.
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