I recently bought a pair of photochromic prescription-lens spectacles, and I was disappointed to find that they don't darken when I'm in my car. I've since discovered that they react to UV light, and that the glass of car windows blocks UV light. I wish that I'd known this before I ordered them. They are not as versatile as I had hoped/expected, because I still have to carry conventional prescription-lens sunglasses in my car.
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L\'escargot by name, but not by nature.
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Interesting. My current glasses are plain, but my last pair were reactolite prescription glasses and they worked fine in cars. They had the added benefit that even when they seemed to be absolutly black to an observer they didnt actually impact much on my ability to see when light levels changed - ie going into a tunnel.
Mine were made of glass (I seem to remember zeiss ? or something) Are the ones that dont change plastic lenses ?
I would have a word with an optician - one of the express places - about getting glass cut - they must come as blanks and then get cut to shape. You can get frames v.cheap on the web, just use an optician for cutting and fitting.
Try asking if they have a blank to test - take it into the car and see if it reacts.
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"You can get frames v.cheap on the web"
That's worth knowing. I did some work once for an optical lab that supplied frames to opticians and was gobsmacked at the mark-up!
I used to wear reactolite(tm) lenses all the time, and they worked fine in the cars that I had, so it may be a change in the way windscreens are made, rather than the lenses. Those purple-tinged Renault ones looks as though they block something!
Since I bought slightly more fashionable frames for everyday wear, I found it preferable to have a larger style for sunglasses anyway, as they block more light.
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Some windscreens block cos you can't use certain satellite seeking (or was it laser seeking?) devices behind then. I'm thinking of the Snooper Neo 6 radar detector thing I had for a short while - but I also recall that no GPS receiver can work behind certain windscreens?
As for cheap specs, I've just ordered two pairs for about £50 from www.optical4less.com - based in Hong Kong and I've read a few bad reports as well as good ones. So I view it as a £50 gamble which I might lose - but if I win it will be considerably cheaper than the £160 a High St chain wanted for one pair of v similar specs.
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They are heat reflective windscreens, and have metalised film in them. So they block certain frequencies of light and radio waves.
This does include GPS signals and probably the UV spectrum.
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I just had a heat reflective windscreen fitted, it is supposed to block Infra Red, which is at the opposite end of the spectrum to UV (BTW our oven door glass is also like this (mwtallic pink) inside)
It does reduce the satellite signal, but it still seems to work fine.
It is less tinted than the original green solar absobing one, but maybe this is the new 70% min Transparency rule? I think the old one was 75%.
These spectacles all work with silver-halide compounds I believe.
They are sensitive to UV, all glass absorbs most UV.
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The laguna screen cuts down GPS from 9-12 sats in view to 4-7.
This does reduce GPS accuracy as there are less references to average.
I installed a GPS reradiating antenna and get my 12.
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I did some work once for an optical lab that supplied frames to opticians >>
I've a pal who runs an optical lab supplying frames and lens made up to customers' eye test results/orders supplied by local opticians.
My other half wears glasses and, after having one of her two yearly eye tests, my pal makes up glasses to her choice of frames (or rimless), complete with lenses - price is a third of what an optician would charge and he's still making a useful profit....:-)
You may have noticed that yet again opticians' staggering markups made the headlines again this weekend.
Ironically you can buy a splendid pair of quality sunglasses, complete with first class frame and lenses, from the major high street stores from around £10 to £30.....;-))
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What\'s for you won\'t pass you by
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I have the reactolite lenses now and go to specsavers. Anyone know if Costco are any good? I want some stylish lenses as I wear them all the time but ideally reactolites again.
Thanks,
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Adam
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I don't know about costco but I did get glasses from ASDA, a couple of years ago now, made using high refractive index plastic, (thin lenses) and saved 1/3rd off the usual price. Only some ASDA stores have such a the facility.
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