Is UV light bad for your eyes? Can UV damage your eyes? What ever did we do before UV coatings were invented and the use of polycarbonate was started?
Is UV light bad for your eyes? Can UV damage your eyes? What ever did we do before UV coatings were invented and the use of polycarbonate was started?
I may be wrong but it is my understanding that polycarbonate lenses by themselves do not provide 100% UV protection up to UV400. Can anyone confirm this?
From the Opticampus forum-
http://64.50.176.246/tools/transmittance.php
But blue light doesn't cause cataracts.
Erik Zuniga, ABOC.
On the flip-side of your statement:
Do not discount the benefits of the electromagnetic spectrum, of which light is a part of.
In a natural(not intensified) state, most of it is crucial or beneficial for human survival.
You asked if UV light is bad in a previous post. Yes, in excessive quantities, it has been proven to be dangerous, but not the whole UV spectrum.
You asked if UV light can damage your eyes. Yes, you can be at risk, if your body possesses the appropriate genetic conditions, and your exposure is excessive.
You asked what the optical industry used BP(before poly). The industry had a arsenal of glass, chemically altered to block UV and infrared light, some of which are still used today. We also had chemical coatings that were surface coated on higher powers to behave uniformly across the lens. Photogrey and Photsun glass also had UV protection when activated, but were known to be partial in the blockage ability.
All lenses, when developed, were tested and verified to be of a specific transmission...........and scientifically proven to do what they were designed to function as.
Eyes wide open
I tried a simple experiment and used the blue light from my computer mouse. It passed through my poly ,A/R coated, transitions extra-active lenses, it passed through a sample of poly with Prevencia A/R and lo and behold nothing came through a cheap yellow tinted clip on.
I don't have a problem with the products, but like Uilleann says, the evidence is too weak to 1. bring it up, 2. talk about what the "free lens" does (blocking blue light).
For what it's worth your OD shouldn't have you on Preservision either.
It's tough to be scientific, apparently.
If you're actually trying to anecdotally connect visible spectrum light in the 500-455 nm range to invisible (and as we all know much higher energy) ultraviolet range - encompassing all three ranges of A, B, & C of course - 380-280 nm...I might kindly suggest a basic physics refresher course. The electromagnetic spectrum doesn't quite work the way it seems you have been led to believe. And of course, the human body doesn't react to different wavelengths equally (remembering of course, that there has not been a single scientific, peer reviewed in vivo study on the effect of blue light on the human retinal cells).
In these cases, it's always wise to remember the sage advice of Neil deGrasse Tyson: "The good thing about science is that its true whether or not you believe in it."
The whole blue light thing may be a moot point soon. Succumbing to peer pressure, and in answering questions concerning blue light from computers the other day, I was explaining and demonstrating to the patient with one of those sponsored counter demonstration thingys. Patient was listening, seemed genuinely interested.
After I did my presentation, he says something like, " yeah but I have adjusted all of my screens to reduce blue light, my phone, my desktop, etc. I'm safe". Was not interested in buying it.
Even my cellphone now has a blue light reduction mode. Wait til everybody finds out.
But I will say, cell phones do keep you up at night.... Have you ever laid there in bed holding your cell phone up while browsing? Then, just as you are dozzzzing off, you drop it on your face? Wakes me up every time.
Children and some young adults can see down to 330nm. With their clear media and large pupils, one could argue that's the age group that needs the most protection. But, exposure to "bad" light might play a role in reducing the incidence of high myopia, with myopic macular degeneration projected to be one of the primary causes of blindness in the world by the year 2050. HEV light may play a more important role, with additional benefits (or harm) yet to be discovered.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3872277/
https://www.brienholdenvision.org/tr...ch/myopia.html
https://www.sciencedirect.com/scienc...52396416305862
Best regards,
Robert Martellaro
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
There is some evidence that zinc, in the AREDS2 formula, is actually bad for some people, exacerbating ARMD. In order to determine for whom it is good and bad, a DNA test needs to be performed... unless your insurance covers it because you have a diagnosis of ARMD, costs something like $750.
AREDS has never been proven to prevent the onset of ARMD. It has only been "proven" to slow the progression. That may sound like slicing and dicing the words, but the fact remains.....
Edit:...just because I thought of it later.... Patients don't realize, and even we professionals forget, that one of our duties is to not make patients waste money on unproven treatments, whether it be vitamins, drugs, and I suppose optical devices and coatings. In this case, a lifetime of buying vitamins or coatings that may or may not result in a better outcome is dubious medicine.
There actually is some science behind not allowing the eye to be exposed to all wavelengths is damaging to the pineal gland...FWIW. Pick your poison. One day coffee is bad for us, the next day it is good. Same with eggs.
Last edited by fjpod; 03-01-2018 at 05:16 PM.
Robert, you make an interesting point. Of course, we all know that a few seconds of sunlight exposure *FAR* outpaces the exposure of *ANY* screen we might use in terms of "blue" light exposure - even hours on end. And of course, children have been going outside since the dawn of human history. And so far as I know - no child has died from overexposure to blue light (and I have to think it is an exceptionally small subset of the population that could be scientifically shown to perceive all the way down to 330 nm.) :) It would seem that the increasing incidence of myopia and it's effects might be far more sight altering problem, would you agree?
+1 fjpod
And to Robert's and Uillean's point, the idea floating around myopia control circles is that outdoor exposure is a retardant to myopia onset/progression.
Everything in moderation, I guess.
Last edited by drk; 03-01-2018 at 06:31 PM.
Obviously, this is a highly contested thread with multiple points of views.
Blue Light...Good, bad, indifferent. Let's look at a few perspectives on this.
Yes, white papers are inconclusive when it comes to the hazards of handheld devices and screen time.
15 minutes of sun exposure equals 10 hours of screen time. HEV exposure/hazards from screens and handheld devices is pretty much a moot point. Debunked! Cross this argument off the list......but not yet. Computer screens do contribute to eyestrain. The print is nothing more than pixels that our eyes strain to see properly, unlike printed media. Multiple hours of screentime without a break does contribute to eyestrain. Being able to warm up the screen helps. Adding a crux/rose/peach/amber/brown tint to a lens helps. Adding AR to reduce reflections helps. All of the above helps. Even an HEV that filters some of the blue light helps. Though this blue light may not affect eye health, filtering it does help alleviate eye strain. Where is the harm in advising heavy computer users to add a tint, AR or HEV coatings? DES is a real thing. How you combat it is up to you. I prefer the DES coatings, because it combines a peach tint and AR together. As a wearer of DES coatings, I can attest to added comfort. My bro-in-law is a video producer and cannot wear anything with a tint in it for color recognition. I put him in a Clear Blue HEV lens with AR for his computer glasses. He no longer complains about eyestrain after marathon editing sessions. Maybe its the placebo effect, maybe not.
Blue light is both good and bad. Too much, and your circadian rhythm may be thrown out of whack, as with not enough. Think about those that work nights and sleep through the day. Yup. Way out of whack. Sleep irregularities, depression, etc. Ever heard of the winter blues?
I can't for the life of me remember the source, but there was an Asian study that linked the LACK of Blue Light to increases in Myopia in children. So, not enough sunlight affects myopia. Maybe our parents were right when they told us too much TV will ruin our eyes? This has nothing to do with the blue light emitted from screens. Instead, there is a correlation of sitting in front of screens as opposed to playing outdoors. So, in this case, wearing HEV filtering lenses is not good for kids.
Blue light deniers, you have a strong case. There isn't enough peer reviews to convince me either. But, and a big but, HEV hazards should not be completely dismissed. 15 minutes of sunlight = 10 hours of screentime. Ok...Ok...Ok...stop beating a dead horse. What about artificial lighting. CFLs emit more blue light than incandescent lamps. LED bulbs emit more than CFLs. More and more institutions are adopting LED lighting for energy savings. More indoor blue light. More exposure to HEV. Look around your favorite supermarket. Look around your favorite mall. Look around your workplace. Heck, look around your own home. LEDs are becoming ubiquitous. Indoor sunlight. More exposure. 10 hours of screentime, right. 3 hours of LED exposure = 15 minutes of sunlight. 8 hours at work. 8 hours awake at home. 16 hours a day exposed to LEDs. An additional hour of accumulated HEV without sunlight per day.
What we need is a peer review on the effects of this additional exposure. Don't even think about mobile devices or computer screens. Artificial lighting is more of a problem here.
The US is a litigious society. It will be a matter of time before some hungry lawyer will use the Duty to Inform against us opticians. Remember Prop 65? Again, as opticians, we should be prepared for the day that this becomes a reality. If, just if, one day, HEV exposure is proven and we poo-pooed it and did nothing, would we be held culpable?
Not saying that which side of the spectrum you need to be on, but I am saying that we really need to think about. If the patient is concerned and requests it, we should have at least one product to offer. DES solutions, at least, even if it is just a tint to recommend.
I've rambled enough. We need HEV to stay healthy. Too much is not good. Too much of anything is not good, as I work on yet another IPA. Absolute proof is still not available. DES is real. HEV hazards from digital devices is debunked. Way too much time is needed to even come close to a few minutes outdoors. Not enough HEV contributes to myopia. Think about exposure to artificial lighting all day long....indoor sunlight, if you will. Think about the eventuality of Duty to Inform. A lot to think about. As with you, I eagerly await peer reviews. I eagerly await reports on the hazards of artificial lighting. Until then, if a patient requests DES, i will offer it. If a patient is concerned about HEV, I will provide a product for them. Where is the harm in that?
Thanks for taking the time to read this to the end.
If science cannot show ANY direct correlation to "blue light" exposure from *any* source, and damage to in vivo human retinal cells, I wouldn't worry about litigation. That seems to be little more than a distraction at this point TBH. Now, if solid, peer reviewed, repeatable, solid scientific research shows differently, no doubt we will all happily change our minds with the presentation of such data. Of course, that wouldn't stand a chance today in any court of law either.
Effects of blue light on the circadian system and eye physiology
Light-emitting diodes (LEDs) have been used to provide illumination in industrial and commercial environments. LEDs are also used in TVs, computers, smart phones, and tablets. Although the light emitted by most LEDs appears white, LEDs have peak emission in the blue light range (400–490 nm). The accumulating experimental evidence has indicated that exposure to blue light can affect many physiologic functions, and it can be used to treat circadian and sleep dysfunctions. However, blue light can also induce photoreceptor damage. Thus, it is important to consider the spectral output of LED-based light sources to minimize the danger that may be associated with blue light exposure. In this review, we summarize the current knowledge of the effects of blue light on the regulation of physiologic functions and the possible effects of blue light exposure on ocular health.
See all of it:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149
lensmanmd- OK I'll play devil's advocate. In our litigious society do you see a potential class action lawsuit against Big E and others for promoting a product that is not proven, and may be, detrimental to vision and health?
That would be an interesting trial!
Or more likely- Like the movie "A Civil Action", How much to make this go away...
See "Table #1 Ultraviolet transmission (cornea, aqueous, and lens) according to age group" in the first link I posted. WRT assessing risk, we both agree that more research is required.
At least more circumspective, mindful of possible unintended consequences.
Best regards,
Robert Martellaro
Last edited by Robert Martellaro; 03-04-2018 at 12:06 PM.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
For what it's worth your OD shouldn't have you on Preservision either.
Drk, curious why you think my doc shouldn't have suggested Preservision?
So, since the sun is the strongest source of blue light- how much blue light do various sunglasses block? I know Transition Xactive block 80% when dark.
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