dedomed emitter with half of the phosphor missing, effect to my eyes?

[johnvilla136]

I have a blf x6 flashlight and put in my newly dedomed xpg2. When i turned on the light, blue light comes out and i wondered what the hell it is because i thought it’s going to be neutral to warm white after dedoming. And to my stupidity i look at it directly while in low mode to see what’s making it blue. I can’t see anything wrong with it so i removed the reflector and use my aspheric lens to focus the emitter on the wall. Well half of the phosphor from the emitter is missing so that’s what making it blue light. I may have damaged the phosphor of the emitter while putting in the reflector.
What will be the effect of it to my eyes because i looked at it directly for less than a second?

[Halo]

You shouldn’t notice any effect to your eyes. Even when there is some slight vision damage the brain is really good at filtering it out so you don’t notice it. Check out the blind spot we all have that the brain just fills in.

Intense blue light is hazardous so I wouldn’t use that led myself.

[johnvilla136]

I read somewhere that the blue light emitted without the phosphor is UV and i am worried that it will damage my eyes.

[Halo]

With Cree leds (and most others) it’s blue, not UV. There are a few white leds that use UV but they are rare.

You can check out the emitted spectrum in the datasheet. Cree XML datasheet Page 4, Cree uses about 440nm –450nm blue. UV starts around 400nm.

[itsonlyme]

I have noticed that it can be extremely disorienting but it was not a Cree led and there was no phosphor coating at all on that one. Remote phosphor was removed

[hank]

What Halo said.
I’ve had this happen to an emitter a couple of times.
Checking the resulting light on my $40 kit spectrometer, http://publiclab.org/wiki/spectrometer
the emitter was putting out some blue well out toward the high energy end verging into the ultraviolet, even though the “color temperature” looked just blue.

There’s no line in nature separating “blue-safe” from “blue-dangerous” from “uv-dangerous” — no sudden change whatsoever.

Once you get into the blue range the photons are energetic enough to cause chemical damage.

Just this year’s papers so far: Google Scholar

Note it’s the tiny size of the bright spot that makes LEDs a (short term) hazard to eyesight.
This was written in 2007 — they’ve gotten smaller and brighter since then.

EDIT: that’s distinct from macular degeneration, which seems to be the long term hazard:
https://www.google.com/search?q=“blue+light”+macular+degeneration

High-Power LEDs Pose Safety Hazards

The output of an LED intended for lighting is usually quoted in lumens. Modern high-power devices, such as the Luxeon K2 line or the Cree Xlamp 7090 XR-E series, can produce more than 100 lm of output from a single LED chip. A typical 100-W bulb produces an optical output of about 1750 lm, however, so why are LEDs more hazardous?
The answer lies in the extremely small size of the emitting region of the LED and, to some extent, the different spectrum of the emitted light. Because the emitting region is small (3 mm2 in the case of the Luxeon K2, for example), the eye can focus the light to form a small image on the retina with a high power density capable of causing localized damage (Figure 1). This damage can be either photothermal or photochemical….
…
… The problem is more acute with blue LEDs, which emit essentially all of their output in the spectral region associated with the retinal blue light hazard. This is formally defined as the 300- to 700-nm range, but the 400- to 500-nm region is the most dangerous.
The Luxeon K2 royal blue LED peaks at around 450 nm, with a width at half height of about 20 nm, and can emit as much as 750 mW of radiant power from a chip less than 3 mm2. Despite being a powerful emitter, it is not perceived as such because of the reduced sensitivity of the eye at these wavelengths (Figure 2). This and similar products from other manufacturers certainly present a risk of retinal damage if used carelessly.

Figure 2:

[djozz]

I think there will always remain some dispute between hank and me about this subject. My opinion is that everything less intense as sunlight (70,000-130,000lux) for brief moment (you do not deliberately keep looking in the sun either) will not directly harm your eyes, our eyes are build to last many years (but not 100) with occasional flashes of direct sunlight . This is blue light of course which is more energetic and your pupils contract less to it as well, so less intensity is needed to do harm, but it still takes quite some light to really damage your eyes permanently.

[B42]

Well its not that it wont directly harm your eyes, its just that you wont be able to tell the difference. It just makes no sense to go on with something that does harm when its cheap to fix: short and sweet is its advisable to get another light or LED to use.

If you use it occasionally, it probably wont be a big deal, you’ll never notice if it does some damage either way unless you are on the edge of a major detectible amount of damage from something else. It makes no sense to use it though when you can go get a $12.99 Convoy S2+ with a 4C tint (even less in the blue than what you started with completely undamaged) for even less eye strain and possible damage. Much cheaper than the increased eyeglass prescription when you are older, or having to have a cataract surgery earlier, or losing your vision a bit sooner I’d say. Since we are living closer to 100, which eyes don’t generally last that long with average usage, small built up exposures do become an issue as you get close to that unknown damage level and get older, and your future self will thank you for the extra couple days of vision, or at least the memories in higher color rendition of the 4C tint

[djozz]

I'd go for a new led too :-)

[hank]

Research keeps coming in on this issue, e.g.:

Review Education Group | Review's Continuing Education

how it can damage the eye and its link to age-related macular degeneration (AMD)

Blue light, which is part of the visible light spectrum, reaches deeper into the eye and its cumulative effect can cause damage to the retina. Furthermore, in certain wavelengths, blue light is implicated in the develop ment of age-related macular degeneration (AMD).1–3 The amount of exposure to blue light varies, depending on the time of day, the location and the season. The average proportion of blue light that’s found in sunlight during the day is between 25% to 30%….
…
… modern lighting—such as LED lights and compact fluorescent lamps (CFLs)—most of which emit a high level of blue light. CFLs contain about 25% of harmful blue light and LEDs contain about 35% of harmful blue light. Interestingly, the cooler the white LED, the higher the blue proportion. And by 2020, 90% of all of our light sources are estimated to be LED lighting. So, our exposure to blue light is everywhere and only increasing.
…
… the specific band of blue light most harmful to the retina and to the RPE cells was identified to be at 415 nm to 455 nm.
The blue-violet light that was discovered as part of this study is a 40 nm band of visible light that causes the maximum retinal cell death. Over time, our eyes are exposed to various sources that emit this blue-violet light (e.g., the sun, LED lighting, CFLs). Combine that with the use of tablets, TVs, computer screens and smart phones, and there’s no doubt our exposure to blue-violet light is on the increase. This cumulative and constant exposure to the blue-violet light is going to accumulate over time and has the potential to cause damage to the retinal cells, which is going to slowly lead to retinal cell death and can in turn lead to AMD.
The level of light emitted by newer energy-saving lighting techniques (e.g., LED, CFLs) is very high. For example, CFLs, white LED light and even sunlight emit high levels of blue-violet light compared to the rest of the blue light spectrum. This underscores the need for us to protect our eyes from the harmful bands of blue-violet light.

EDIT to add:

I don’t think there’s a right-or-wrong divide here; I’m into my later 60s, had my first cataracts show up in my 40s, have an early type implant replacement lens that passes well up into the ultraviolet (I can see spectral lines that aren’t visible to people with normal lenses)

Here’s another guy with the same situation: Ultra Violet SUPERPOWER (!) after Cataract Surgery with Crystalens - color glow
And another: http://ehilbert.wso.net/Starlight/deep_sky_wonders.htm (scroll down to the last paragraph)

So I’ve had to be very careful since then about exposure to light, because I have nothing protective at all between my retina and the outside world. My retina is as exposed to damage as a young child’s whose natural lens hasn’t started to get yellowish yet.

That’s the real caution as far as I’m concerned. Not old guys like me who’ll never notice the damage — but young people coming along in an environment unlike anything people have lived in before.

[B42]

Sorry I missed the first time that this was a BLF X6! Not only can you probably sell it to someone who wants to mod it and recoup the money, but BLF D80 and A6 group buys will be coming out soon, both of which have higher output and more mode selections for around $20 if you are willing to wait.