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Extreme near/far-sightedness: LED Color skew

FM Former Member
well I see there is one annoying "problem" with tri-color LED fixtures but it is not going to be apparent to people who have either normal vision or who wear contact lenses.

I am extremely nearsighted, to the point that my natural focal length is approximately six inches in front of my face. I don't like contacts so instead I live with the -9.5 index "Coke bottle" glasses.

A problem with such high index eyeglasses is that since the lens does not move with the eyeball, the lens can only provide optimal focusing when the eye looks straight ahead through the center of the lens.

When the eye is looking off-axis through the lens, the lens acts like a prism that gets gradually stronger the further from the center the eye is looking.

Consequently when I look through my glasses at the world with my head turned far up/down/left/right, I see color fringing around the sides of the object.

Looking up through the top right corner of the glasses at a white fluorescent light shows a dark blue color fringe on one side, and a bright yellow fringe on the other. Looking through the bottom left corner and the fringes flip over.


These tri-color LED lights are really annoying in this regard since they emit only a very narrow spectrum of red, green, and blue.

If I set the beam to "white", and if my view is not perfectly dead-on centered through my eyeglasses, I see three separate images that do not overlap, and these images spread further apart as I move my head to look away from it.

It looks vaguely out of focus, but it isn't. They are sharp but three separate and slightly overlapping R/G/B color layers.

I get this real bad with outdoor tri-color LED signs as well. Most outdoor signs are basically an unreadable misaligned color mess for me, unless I center my head to look straight at it through the center of the eyeglasses.


I know, I know, get contact lenses and the problem will go away. Contact lenses move with the eyeball, so the cornea and lens are always aligned on the best axis for accurate color rendering.

But still, this is an annoying side effect of tri-color LED lighting systems for people with strong eyeglass prescriptions.

- Dale
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S Studio42 (Guest)
Interesting observation. Have you considered getting a white cane?

Just kidding. I have a close friend who is legally blind.

Your observations are definately odd. I wear glasses. I'm nearsighted, but I'm not wearing coke bottles, than goodness. And for me, contacts are NOT an option I'm willing to consider. Don't go there, not happening. And I have an astigmatism too, but they have contacts that correct for that as well. No, contacts are NOT a choice for me.

My wife made me get smaller glasses, With the smaller lenses, I noted that UNLESS I looked dead center through them, I would get distortions and focus issues. Very annoying while driving. It's enough to be noticed, but COULD be distracting because then I'd start paying attention to it and the more I noticed it the more it made me angry. 2 additional sets of glasses later, it appears with the smaller polycarbonate lenses, I don't have these issues anymore. I mean, why have eyes that can move if you have glasses that make you look straight ahead. Hey, I'd like to use the WHOLE LENS!

I am wondering if you have any sort of options available to address the type of lenses you have to use. I take it due to your extreme myopia, it's limiting your options.

Now, ADJ does make a gel specifically for the LED cans. Would something like this smooth it out enough to make things more readily usable for you?

Too bad you can't show us how it looks. I'd be interested in seeing it myself.
FM Former Member
It is actually not surprising. The thickness of the lenses are acting like a prism and breaking light apart into their respective wave lengths. Since tri-colors combine red, green, and blue on very tight wave lengths, when the light hits a prism, it will split into red, green, and blue respectively.

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