Prescription spectacles UV protection

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rmurphy195
Posts: 2199
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Prescription spectacles UV protection

Post by rmurphy195 »

I’m not going to go into how I came at the decision to do so,, but a couple of weeks ago I decided to take my spectacles back to Specsavers to have them tested for their UV blocking ability.

One is a pair of reading glasses I had made up, with Specsavers own UV400 coating.

The other is a pair of Essilor Orma Crizal UV varifocals, which are supposed to have a very high level of UV protection –I had asked for 100%, to replace a pair of Transitions which I had had for a year and which had a disadvantage decided I couldn’t live with any longer (they go dark even in dull weather).

The reading glasses were blocking 95% of UV light instead of 100% – a puzzle to Specsavers who weren’t quite sure why this would be, but they re-coated them FOC and re-tested them.

The Essilor lenses were blocking only 75% of UV – a performance equivalent to a pair of non-UV blocking lenses I had had before the latest Crizal UV lenses were introduced. Specsavers contacted Essilor who were in turn puzzled, and offered to replace the lenses FOC, wanting my original lenses back for analysis. Specsavers added that when the new lenses arrived they would test those to ensure they were up to the mark.

Now there could be any number of reasons why there was a discrepancy between what I asked for in these lenses and what I was provided with – at one end of the spectrum it could be the wrong lenses ordered or provided, to a manufacturing or quality control issues with Essilor at the other, so I was going to sit on their until I found out the results of the analysis.

However today I had a call from Specsavers to apologise for the delay. They had checked the Essilor lenses on arrival and found in their words that “they didn’t pass quality control checks” so had sent them back to Essilor for a further replacement. This means that Essilor have, on the face of it (to be confirmed), provided lenses that were not up to the required quality of UV protection on at least two occasions, several months apart.
At this stage we don’t know what the problem is or where it lies, however if you do have the Essilor lenses and, after reading this, you are uncertain then take them to your optician and have them checked. It's free (at least with Specsavers)

In the meantime, as and when I know what is going on (whether it is in the ordering/administration chain, or manufacturing problem, or even the way I clean them), I will update this thread.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !
Tangled Metal
Posts: 9505
Joined: 13 Feb 2015, 8:32pm

Re: Prescription spectacles UV protection

Post by Tangled Metal »

How long does the testing take? Is it a case of weeks without glasses or drop them off and a few minutes to hours later is done?

I need my glasses when awake and have only two pairs. Not keen to be without a spare pair for long.

BTW I've got Specsavers' ultra thin and light lenses (the most expensive lenses they do as standard). This is due to a high prescription. AIUI they have pretty much all the non-tinted coatings included due free. Scratch resistant, uv, anti glare, etc. Plus I thought the plastic used has an inherent level of uv protection due to the structure of the material. As in high 90s%.
rmurphy195
Posts: 2199
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: Prescription spectacles UV protection

Post by rmurphy195 »

Tangled Metal wrote:How long does the testing take? Is it a case of weeks without glasses or drop them off and a few minutes to hours later is done?

I need my glasses when awake and have only two pairs. Not keen to be without a spare pair for long.

BTW I've got Specsavers' ultra thin and light lenses (the most expensive lenses they do as standard). This is due to a high prescription. AIUI they have pretty much all the non-tinted coatings included due free. Scratch resistant, uv, anti glare, etc. Plus I thought the plastic used has an inherent level of uv protection due to the structure of the material. As in high 90s%.


It takes minutes - I spent about 1/2 hour in the shop, but that was mostly the guy going upstairs to do the tests, then coming down with a puzzled frown to check the original order the see what I was supposed to have. And calling Essilor. And recoating the reading glasses.

The Orma lens has inbuilt UV protection, the rest is coatings etc. put on by Essilor for their lenses, before they send them to Specsavers. That's how I understand it anyway. The inherent blocking of the plastic blocks out most of the uv that passes through the lens, the coatings as I understand it increase that and in addition, take care of UV reflected off the back of the lens into your eye. The bigger the lens of course the more your eye is covered - a peak or better still an all-round brim on your hat adds to the protection.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !
Warin61
Posts: 192
Joined: 16 Nov 2016, 8:51pm

Re: Prescription spectacles UV protection

Post by Warin61 »

First ... you never get 100% or 0% ... well very seldom.

You may get to the limit of the measurement system - say the system measures to 1% (resolution is the technical term). So a reading of 100% could be 99.6% but displayed as 100% due to the 1% resolution problem. Some time later (years) there may be a new measurement system with a resolution of 0.05% .. and that may give you a 99.60% reading. So I take 100% or 0% as marketing rather than absolute fact.

Next you have side leakage around the glasses.

And then you compare to the person who has no glasses.

UV has several 'bands' ... UVa, UVb for example. Possibly the manufacture is claiming 100% UV .. but UVb, and the retailers equipment is measuring UVa.

---------------------------
I don't pay extra for UV protection. The difference between 90% and 99% is not that much, you get more by putting on a hat.
Pay for things like finger print proofing.
rmurphy195
Posts: 2199
Joined: 20 May 2011, 11:23am
Location: South Birmingham

Re: Prescription spectacles UV protection

Post by rmurphy195 »

RESULTS -

First of all can I ask that this be left without additional posts so that anyone looking can see immediately what this is about and read the warning that I have intended, to make their own decision? Diverting to general discussions about expectations of testing etc. could be done on a separate thread perhaps.

First of all my lenses, which blocked 75% of UV have now been replaced - twice. the original replacements failed testing by specsavers and sent back to Essilor, to be replaced again by Essilor who have now provided lenses up to the correct specification.

At the same time (May of this year) we ordered similar lenses for my wife to try (Comfort Orma Crizal Alize). These were tested today and found to be blocking only 87% of UV, so these are going to be replaced. A few weeks after the original purchase that she ordered a second pair of identical specs (same lenses) but with a tint added so she has sunglasses. These tested as blocking 100% of UV. Whether the Essilor coating have been supplemented by the tint that Specsavers applied we neither know, nor care.

To put this into perspective, the Orma lens material according to Essilor blocks 75% of UV, the extra is down to the Crizal coating (or the Alize, whichever). This suggests that the coating was not effective at all on my lenses, and only partially effective on my wife's. Reason is unknown, Essilor will test the returned lenses and I have requested that I have the results, because Iwant to know the cause. Is it Essilor quality (the saga of my replacements suggest that may be the case), is it the cleaning degrading the lenses, or whatever.

So if you have ordered these lenses from your optician, and you have concerns having read this post, simply take your specs back to your optician and have them tested.

Then maybe any results that people have had could be added to this thread, focusing on the subject in hand.
Brompton, Condor Heritage, creaky joints and thinning white (formerly grey) hair
""You know you're getting old when it's easier to ride a bike than to get on and off it" - quote from observant jogger !
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