Topic: Photochromatic lenses (Read 8080 times)

BarryM · « **on:** April 30, 2007, 08:34:37 pm »

Opticians' adverts push the merits of spectacles with photochromatic lenses - the ones that darken in sunlight and lighten in low light conditions. Those who wear them while driving may be interested in the following report on the MAIB website and the recommendations for those needing to keep a good lookout.

http://www.maib.gov.uk/cms_resources/Ouzo_Flyer%20to%20Merchant%20Shipping.pdf

Food for thought?

Barry M

HS93 (RIP) · « **Reply #1 on:** April 30, 2007, 08:48:08 pm »

I have worn them for at least 15 years but only with glass lenses as they are about 3 or 4 times faster to change than plastic, the older ones where very slow changing, long tunnels where a pain you had to take them off before you got to it and cover them up then pop em on when you got in.

Peter

Colin Bishop · « **Reply #2 on:** April 30, 2007, 08:50:32 pm »

Yes I read that too - don't wear them for driving at night. Actually I thought it was a bit obvious as these types of glasses never completely lose their tint indoors. Funnily enough you will often find that they do not darken when driving in sunlight. This is because many cars now have tinted windscreens which filter out the UV rays which cause the photochromic lenses to activate.

NB: Don't wear normal sunglasses when driving in the Alps etc. As soon as you go into a tunnel....

catengineman · « **Reply #3 on:** May 01, 2007, 12:50:59 am »

I have and do wear photochromatic glasses ALL the time, Why because I have to in order to avoid head ache and eye strain.
Have I noticed any thing with the rate they change NO! mine change very quickly both ways and they do go clear indoors. But then at over £300 per pair you would expect them to.
I have totally clear specs for close work but these are slightly stronger lenses (plastic) not glass.

Richard,

tigertiger · « **Reply #4 on:** May 01, 2007, 03:19:06 am »

I was told by my optician that in very hot weather (30 degree+) they don't react properly.

So OK in UK then LOL

anmo · « **Reply #5 on:** May 01, 2007, 08:58:52 am »

Quote from: Colin Bishop on April 30, 2007, 08:50:32 pm

NB: Don't wear normal sunglasses when driving in the Alps etc. As soon as you go into a tunnel....

Isn't that rather like reminding people to drive through these tunnels on the right side of the road? I've driven through more Alpine tunnels than a few on this forum have had hot dinners, and they don't exactly take you by surprise. All I've ever done is to pull the glasses down my nose for the short ones, and take them off for biggies like the 17k Vorarlberg one. You see, you don't need sunglasses in a tunnel.....

Colin Bishop · « **Reply #6 on:** May 01, 2007, 10:09:39 am »

Anmo - you may be hawk eyed but a lot of us actually need glasses to see properly. If we take them off in the tunnel. or even take them off at all when driving......

anmo · « **Reply #7 on:** May 01, 2007, 10:38:01 am »

Colin, it was your choice of words, namely 'normal sunglasses' that confused me. Silly old me for thinking that you meant, well, normal sunglasses.....

DickyD · « **Reply #8 on:** May 01, 2007, 11:00:22 am »

BarryM · « **Reply #9 on:** May 01, 2007, 11:51:32 am »

The MAIB refernce was not to the speed of change but to the fact that even after the lenses have fully cleared, they still obstruct the passage of light by a significant amount. Thus, used at night or in any condition of poor light, they will not give vision as good as provided by plain lenses for spectacle wearers. Has anybody ever seen a warning to this effect in adverts for photochromic lenses?

Barry M

HS93 (RIP) · « **Reply #10 on:** May 01, 2007, 12:00:58 pm »

this answers most questions

http://www.college-optometrists.org/index.aspx/pcms/site.Public_Related_Links.Spectacles.Photochromic_lenses/

http://www.eye-care.org.uk/item_view.php?item_id=118&content_id=5

Peter

DickyD · « **Reply #11 on:** May 01, 2007, 12:07:46 pm »

Amazing 11 replies about a pair of glasses !! ::)

anmo · « **Reply #12 on:** May 01, 2007, 12:21:42 pm »

Quote from: DickyD on May 01, 2007, 12:07:46 pm

Amazing 11 replies about a pair of glasses !! ::)

Given the age of many users of this forum, we could probably have a similarly lengthy discourse on hearing aids, walking sticks, Stannah stairlifts, or even Zimmer frames.

Colin Bishop · « **Reply #13 on:** May 01, 2007, 12:39:49 pm »

Quote

Silly old me for thinking that you meant, well, normal sunglasses.....

Yeah, silly old you! Normal as opposed to photochromic! :)

I'm told Zimmer frames make great TX aerials - you can earth them.

BarryM · « **Reply #14 on:** May 01, 2007, 12:42:08 pm »

Quote from: HS93 on May 01, 2007, 12:00:58 pm

this answers most questions

http://www.college-optometrists.org/index.aspx/pcms/site.Public_Related_Links.Spectacles.Photochromic_lenses/

http://www.eye-care.org.uk/item_view.php?item_id=118&content_id=5

Peter

But they don't put it in their ads......

anmo · « **Reply #15 on:** May 01, 2007, 12:45:45 pm »

Quote from: Colin Bishop on May 01, 2007, 12:39:49 pm

Quote
Silly old me for thinking that you meant, well, normal sunglasses.....

Yeah, silly old you! Normal as opposed to photochromic! :)

I'm told Zimmer frames make great TX aerials - you can earth them.

"Have you taken your pills Mr Bishop? We'll go out for a nice walk later, I SAID, WE'LL GO OUT FOR A NICE WALK LATER !!!!"

Colin Bishop · « **Reply #16 on:** May 01, 2007, 12:49:44 pm »

PARDON!

BarryM · « **Reply #17 on:** May 01, 2007, 12:58:13 pm »

Now, now Boys! Play nicely or Matron will be along with the rubber hose again - and you know what happened last time!

Colin Bishop · « **Reply #18 on:** May 01, 2007, 01:01:03 pm »

Quote

Now, now Boys! Play nicely or Matron will be along with the rubber hose again - and you know what happened last time!

Yes, I nicked the syringe and hose to get the water out of the bottom of my boat.

BarryM · « **Reply #19 on:** May 01, 2007, 01:03:19 pm »

That will get you an extra hour locked in the broom cupboard!

sheerline · « **Reply #20 on:** May 01, 2007, 01:12:10 pm »

I used to wear sunglasses whilst working on the airfield as the reflection from the vast concrete areas became unbearable and could result in headaches. I tried all types including reactive types. I also used to wear them whilst model flying but found that continual use actually impaired my eyes ability to deal with natural sunlight, resulting in a need to wear them more and more. I made a concious effort to avoid wearing them at all and found my eyes reverted to normal tolerance of natural sunlight. The only time I ever wear sunglasses now is when exposed to highly reflective surfaces.

anmo · « **Reply #21 on:** May 01, 2007, 01:16:28 pm »

Quote from: BarryM on May 01, 2007, 01:03:19 pm

That will get you an extra hour locked in the broom cupboard!

Along with Boris Becker.

DickyD · « **Reply #22 on:** May 01, 2007, 03:59:06 pm »

Quote from: sheerline on May 01, 2007, 01:12:10 pm

I used to wear sunglasses whilst working on the airfield as the reflection from the vast concrete areas became unbearable and could result in headaches. I tried all types including reactive types. I also used to wear them whilst model flying but found that continual use actually impaired my eyes ability to deal with natural sunlight, resulting in a need to wear them more and more. I made a concious effort to avoid wearing them at all and found my eyes reverted to normal tolerance of natural sunlight. The only time I ever wear sunglasses now is when exposed to highly reflective surfaces.

Best not look directly at the heads of 90% of this forum then

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Author Topic: Photochromatic lenses (Read 8080 times)

catengineman