I see what you mean. Does the intensity still matter as well? Like if the light is twice as bright does it do more damage, or is it pretty binary (as in it's either doing damage or it isn't).


Yeah they seemed to be saying that phone light was worse as it contains mainly blue light, whereas sunlight contains a lot of blue, but also a lot of orange, yellow and green, so it kindof negates the effect? Something to do with the eye resetting.

So light intensity is defined as the power per area is covers:

\(I=\frac{Power}{Area}\)

Power is measured in watts, and watts has units kg * m^2 / s^3.

We can calculate power by taking the energy of the light source, and dividing it by the time that the person is exposed:

\(\frac{E}{t_{\left(s\right)}}=P\)

To find the energy of a light source, you use this formula:

\(E=\frac{h\times c}{\lambda }\), h is a constant, c is the speed of light, and \(\lambda\) is the wavelength in question.

Therefore, intensity takes into account the time one's exposed and the area that the light it covering. Given all that we know, the closer you place your phone to your face, the greater the intensity. My opinion is that intensity does matter because of the proximity the phone is placed to your eyes, which means more power concentrated in a smaller area.


That's another thing to consider, because when these tests are done, they eliminate all other wavelengths, so you don't get any other wavelengths affecting the outcome. That's ultimately how science experiments work. In addition, it was performed on animals because no sensible human could ethically take part in the study, as it can ultimately harm them.

So is the other wavelengths thing still kindof an unknown? As we haven't done any tests with it?

TBH the main reason I am worried is because over the last few years I have used my phone in the dark for a few hours every night, and I also normally end up using my computer for a few hours in a dark room too.

You mentioned earlier that it would only mean you got problems with your eye earlier, is there anyway to know how earlier? (I mean I also use my computer a lot in the light, but everybody does that so I'm less worried about it)?

We're more concerned about blue light because it's closest to ultraviolet light:



Notice in the image how the wavelengths get smaller as you head left from blue light, which means they hold more energy


You can't quantify it because there are too many factors to consider, most important being genetics.

Word of advice, stop using your devices in the dark if you don't need to!

The original things that was said by somebody on another forum, was that the presence of longer wavelength, will cause the cells to "stay photobleached" which stops them "resetting" and lessens the damage caused. I'm not sure if this is true.


Would the genetics effect how much damage the light does? Or would it just determine at what age AMD could start if you didn't do any damage. (i.e. if one person would "naturally" get AMD at 70, and another at 50, and they both exposed themselves to the same amount of blue light, is it possible it causes one of them to get it 10 years earlier, and the other 30 years earlier? )

So the longer wavelengths resets the cells, acting as an antidot? I wouldn't know anything about that, but probably true. Do they have any sources?


Your genes hold information that translate into proteins. Some proteins are more equipped to withstanding damage than others. Question is, why would you put them under stress if you knowingly acknowledge that starring at a bright screen at night isn't healthy? It's like your tempting nature...

I couldn't find any sources for it (but I wouldn't really know what to look for). If it is true though, I assume looking a screen in dark would be significantly worse as your eyes wouldn't be resetting as there is only the screen light, not any natural or
"lightbulb" light?

I have stopped using any screen in the dark since I found out it can be harmful, I'm just concerned I have already done a lot of damage based on what I already did. I'm not sure how much though, or whether it should be a concern.

There's no way to reverse any damage done, but it's better that you know now than later. I salute you for wanting to improve your life.


Most doctors will recommend that for every sedentary 20 minutes of screen time, you take 2 minutes looking away. Perhaps this acts as the "reset" switch of which those other members are discussing.

It's possible that even if I have done some damage, the fact I know actually know about the potential harm light can cause, I can prevent future harm that would have happened anyway, essentially meaning I end up in a better situation overall I suppose.

 
I know it's impossible to accurately know, but do you think I should be concerned based on how much I have used a screen in the dark in the past? (i.e. would you be worried were you in my situation) (I'm about 20 btw, can't remember if I said my age before).

Also (this is probably another kindof "impossible to accurately answer" question), but do you think it's likley a treatment for macular degeneration will be developed some time in the future? I've read some stuff about stem cell trials, but it's difficult to tell how well that will go, I imagine your guess would be better than mine.

Okay, so you're early 20... we all do stupid sh@* when we're young. For me, I started to body-build at the age of 15 even though I was warned countlessly not to by my parents. To this day, I feel perhaps it may have stunted my growth, since I used to lift a lot of heavyweights (obviously). There's no study that confirms body-building stunts your growth, but you always question it at the back of your mind -- what if I hadn't?

Anyway, no regrets, I did it for self-defense, because I was bullied a lot in high school - most of it was my fault, but still. After a year, all my bullies stopped bugging me, so it only encouraged me further. I eventually stopped once I reached 19, began university, and forgot all about it. That being said, as long as you've stopped, it gives your cells the chance to adjust, and you should be absolutely fine.


Age-related eye conditions are rarely treated, so I doubt it. Glasses are a huge industry, so unless something spectacular gets discovered, like using stem cells somehow to renew cells near the retina, I don't think that'll happen in our lifetime.

By adjust do you mean like they may be able to go back to how they were? Or just that it shouldn't really be severe damage at all if I start taking a lot better care of my eyes now?

I think that's what the trials were about, using stem cells to regrow (or replace, not sure if there's a difference really) the cells right in the middle of the retina. It was just for AMD, not for glasses-type problems. I think to an extent we have already cured that kindof eye problem, so I think you're right there probably won't be much more research done on lens problems. I imagine stem cell treatments could be a huge industry though.

Do you think being a bit photosensitive means blue light is likely to be more harmful? I don't know if it's actually anything specific, but I've always found myself being more sensitive to light than other people. I can't really be outside on a proper sunny day without sunglasses or a cap (or squinting all the time which hurts my head). I'm not even sure if it's an eye thing, it may be more to do with your brain than your eye.


I did some looking into the genetic aspect of AMD, I found some claims that the amount of cases that aren't genetic is about 1/5. Is a "non genetic case" just one where someone wouldn't have got it within their lifetime naturally, but did due to other factors (like smoking or stuff like that?). Neither of the two grandparents I know are blind at all, and neither of my parents nor uncle/aunties are (although they are all only about 50-60).

Sounds normal to me. I like wearing glasses because it enhances my vision on a bright day, especially as I cruise around in my car. I squint while I'm swimming in the pool, that's why we evolved with eyelashes and brows, nature isn't stupid.


That means you're born with good genes! Blindness is relatively rare, so unless you're a 15th century astronomer who starred at the sun his whole life, you don't need to worry

I assume everyone still has the aging processes in the eye? Even those with good genes, it's just a lot slower then people who are genetically predisposed to getting AMD?

Right. For instance, my grandmother didn't need eye glasses her whole life, she lived to 85. She also experienced virtually no hair loss. Bless her soul.

I hope inherited those genes