[Tig] Macular degeneration, etc. caused by the blue-violet light of tablets, smartphones

Richard Kirk richard at filmlight.ltd.uk
Fri Apr 18 09:33:51 BST 2014


Hi.

Just read Dave Pickett's note. That's bad luck, Dave. Hope you get to the bottom of it, and it's not macular degeneration.

I would be surprised if it was the light from the screen, though I may be mistaken...

The OLED monitors I have measured showed nice, clean Gaussian peaks in the red, green, and blue like  textbook diagram. The backlights to LCDs have a violet band. You see the same violet band in energy-saving bulbs, so I am pretty sure that is well-studied and harmless for most of us. If you can stand an energy-saving bulb then it won't be that violet band at least.

It would be very strange for a display to emit ultra-violet by design. You could easily add a phosphor and turn it into a useful, visible colour of your choice. Anyhow, ultraviolet is not good for organic stuff, including the organic LEDs themselves, so they would be degraded.

The speed of your reaction is remarkable. Either that monitor is pumping out more UV than you happily tolerate on a sunny day, or you are very sensitive to something in particular. But it does allow us to do some experiments if you can bear to be in the room with the thing.

Have you got a spectrometer that measures the ultra-violet? No, neither have I. Okay, let's try something else. You can get 
plastic laboratory UV safety goggles. These are mostly yellow so can't grade in them, but we could see whether your eyes still react. Even easier, do you get the same reaction when the monitor is on but dark? Or when the monitor is bright but you are wearing good sunglasses? If we can rule out light, then you are no better off, but at least we will be looking for the real cause, whatever that may be.

The other bit I might disagree with is the 'macular degeneration caused by..' in the title. Macular degeneration is usually taken to mean a reduction in the macular dye, and increased sensitivity to UV, amongst other things. This happens to people who have low macular dye density, but as far as I know, this lack of dye is a symptom, and not a cause, though it may in turn lead to an increased irritation from near UV. 

People have suggested eating things such as yellow peppers and paprika, that contain the same sort of zeaxanthins as you have in the macular dye. This sounds convincing and scientific, but I don't think people have established that eating it gets it to your eyes. Eating fatty foods and getting fatty deposits on your arteries also sounds like a convincing causal connection, except that the fat has to be digested and turned into something else to get into the blood stream, and then turned back again. Chow down on yellow foods by all means, but do not look for miracles.

Note: I am not a proper doctor, but I did get interested in the amounts of macular dye, as it causes our central vision to be less sensitive to the blue-violet than the periphery, which has all kinds of consequences when you are trying to balance the overall sense of white balance in a projected image.

Long story short:

Take out the "Macular degeneration caused by the blue-violet light" from the title. None of that bit is proved, and every bit could be wrong. You have a severe reaction to a particular monitor. It could be chemical, noise, sound, ultrasound, radio emissions, flickering, or a psychological trauma from childhood that causes you to react to the model number on the case. Who knows? It may not be macular degeneration. If it is macular degeneration then my sympathies, but no-one really has an idea what causes it yet, and that may just be happening anyway and making you more sensitive to other effects.

Apologies for the long post, but intriguing cases like this bring out the Sherlock sumfink rotten...

All the best.
Richard Kirk
 
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