BS: Scratches in Glasses Question???

Subject: BS: Scratches in Glasses Question???
From: Bobert
Date: 24 May 06 - 12:22 PM

Well, this certainly isn't as excitin' as a new revelation of wronmg doing by the Bushites but here goes...

Few days ago I was weed eatin' anmd got lots of weed guts on my glasses which I ain't sure is glass 'er plastic but maybe that ain't even relevant... So we had jus bought one of the 3M crubbers which is palstic and so I cleaned the weed gutys off the the 3M scrubber...

Bad idea 'cuase whatever these glasses is made of it left scratches in 'um and now lookin' thru 'um ain't no fun...

So my question is: Is there anyway to polish out scrathes in eye glasses??? The are the verilux or verivision or what ever with correction for both far and near sight...

Blind Bobert

Subject: RE: BS: Scratches in Glasses Question???
From: John MacKenzie
Date: 24 May 06 - 12:29 PM

Mmm not a good move there Bobert, obviously they're plastic. Rubbing gently with metal polish will remove some of the scratches, but I do mean gently, and with a circular motion and a lint free cloth. DuraGlit or Brasso is what I use for my watch 'glass', the wadding in DuraGlit is pretty soft.
Just be carefull, do it gently, and keep cleaning it off and checking that you're not being too rough.
It won't remove them totally unless they are very lightly marked, you'll just have to do the best you can.
You could 'lose' them and claim the insurance!
Giok

Subject: RE: BS: Scratches in Glasses Question???
From: TheBigPinkLad
Date: 24 May 06 - 12:49 PM

Go to an optician shop and ask them to buff the scratched lens. They're quite good at it and will usually do it gratis.

Subject: RE: BS: Scratches in Glasses Question???
From: gnomad
Date: 24 May 06 - 12:49 PM

Repolishing will remove any coating which you had, maybe UV protection, or anti-scratch, though the latter wouldn't seem to have worked anyway.

As they sound about unuseable as they stand, what is left to lose? A metal polish would be my first choice, and probably finish off using toothpaste. Above all keep checking on progress.

Might be worth checking with a local optical lab if you have one. They probably have the means of refinishing the lenses, and it ought to be cheaper than new ones.

Subject: RE: BS: Scratches in Glasses Question???
From: frogprince
Date: 24 May 06 - 12:52 PM

If you have a palm sander, use 80 grit on them, then 150, then 300, then 600, then 800. You might have to use some 1200, and finish with some automotive rubbing compound.

Subject: RE: BS: Scratches in Glasses Question???
From: Clinton Hammond
Date: 24 May 06 - 12:58 PM

Go get new glasses and never never never do that again!

Subject: RE: BS: Scratches in Glasses Question???
From: Rapparee
Date: 24 May 06 - 01:32 PM

Clinton's got the right idea. Or see if an optical shop can buff the scratches out. Don't try it yourself.

You could, by polishing them yourself, change the lenses to a different prescription, or make something that's barely tolerable completely intolerable.

Subject: RE: BS: Scratches in Glasses Question???
From: mack/misophist
Date: 24 May 06 - 02:46 PM

If state law permits, try to get lenses of tempered glass. Most states have outlawed it, though, because of the liability question. If it's not available, get the hardest thing that is, probably be a kind of acrylic.

Subject: RE: BS: Scratches in Glasses Question???
From: Liz the Squeak
Date: 24 May 06 - 03:38 PM

Or get yourself a pair of safety goggles that go over your eyeglasses and wear them whenever you play with the weed whacker again!

LTS

Subject: RE: BS: Scratches in Glasses Question???
From: Bunnahabhain
Date: 24 May 06 - 05:47 PM

I've done lots of polishing of fibre-optic connectors. I have some idea what I'm doing. Go and buy some new glasses, or lenses for the current pair. Get your prescription checked as you do, unless it's been done recently. No point getting new lenses if they're wrong.

If those scraches in your glasses are of any size at all, it will be nigh on impossible to remove them at home. Trying to get down to a acceptable optical finish with the abrasives and tools designed for the job is quite hard, even with some practice, and that's on a circle one two-hundredth of an inch across ( 125 microns). Doing so with improptu stuff, on a much larger area could be a fun job. I'm not saying don't try, but regard it as a project, to gain a spare pair or glasses, not fixing your only pair.

Subject: RE: BS: Scratches in Glasses Question???
From: Bee-dubya-ell
Date: 24 May 06 - 06:15 PM

Bobert lies! Here's what really happened...

Bobert was, as he claims, cutting weeds with his new string trimmer. Now, as we all know, string trimmers cut with a monofilament line similar to fishing line. That line is held in a spool on the end of the trimmer shaft and a spoolful is good for about an hour's work before it runs out and needs to be refilled. So, after about an hour's cutting the trimmer ran out of line and Bobert took it into his workshop to refill the spool.

When he took the spool apart, there was about a foot of line left inside it. "Hmmm..." said Bobert when he saw the length of line, "I have an idea!" Now, Bobert had been having trouble with his glasses slipping down while he was working and they had almost fallen off once or twice, so he decided to tie the monofilament scrap to the earpieces so that if his glasses should fall off they would just dangle around his neck instead of falling to the ground and getting chewed up by the trimmer.

Well, somehow, in the process of replacing the string in the trimmer's spool and fashioning the safety lanyard for his glasses Bobert managed to tie the wrong piece of string to the left earpiece of his glasses. That is not a real easy thing for most people to do, but it was simple enough for Bobert. Needless to say, when Bobert cranked the trimmer back up it snatched his glasses from his head and spun them through the weeds at about 1600 RPM which resulted in the scratched lenses.

It also gave Bobert a mild case of whiplash which he was going to bring up next week as soon as he could either come up with a suitably colorful story for how he got the injury or figure out a way to blame it on the Republicans.

Subject: RE: BS: Scratches in Glasses Question???
From: Bobert
Date: 24 May 06 - 06:48 PM

Well, you can sho nuff put a damper on a good story, Beezer... An' I had a dandy worked up fir the whiplash... An' believe it or not, the Repubs weren't goin' to be in it...

But, alas, now you'll never get to hear it since you pulled my covers...

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 24 May 06 - 07:52 PM

If you needed the glasses to see the weeds, then you're not letting the weeds grow long enough. IMO.

Hell, winter's comin' in six months. That'll kill 'em off soon enough.

Subject: RE: BS: Scratches in Glasses Question???
From: The Fooles Troupe
Date: 24 May 06 - 08:12 PM

Sounds like you weren't playing with just the Weed Whacker Wobert!

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 24 May 06 - 08:25 PM

Uh, Bobert, did you, uh, well, uh--look, exactly what kinda weed we talkin' about here?

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 24 May 06 - 09:16 PM

Bobert, some good advice above, and some nonsense. 1. Go to lens crafters (or whatever) and ask whether they can polish out the scratches. Where you bought them is the best place.
2. If no can do, ask if new lenses can be fitted- you might save some if the frames are still in production.
3. Buy a new pair (but have your eyes re-checked first by your opthalmologist to see if your prescription needs an update). Buy the protective goggles recommended by Liz.
ALL of the above already posted and good advice. I was lucky to have an optician working in a lab where I was employed. All eyeglasses benefit from periodic professional cleaning and slight re-polish (if not those stupid coated things).

NEVER try it yourself unless you have had training.

Subject: RE: BS: Scratches in Glasses Question???
From: wysiwyg
Date: 24 May 06 - 09:16 PM

There is actually a product sold for just the purpose of filling in fine scratches. But I would check with the optician FIRST.

~S~

Subject: RE: BS: Scratches in Glasses Question???
From: bobad
Date: 24 May 06 - 09:27 PM

Bobert, a little advice for the next time you are compelled to whack weeds, simply wash the residue off your specs with soap and water, better yet wear a protective face shield and avoid this siuation entirely, or even better, do as I do and have your wife perform the murderous weed deed.

Subject: RE: BS: Scratches in Glasses Question???
From: Rapparee
Date: 24 May 06 - 09:55 PM

The toughest lenses available in the US, as far as I know, are made from polycarbonate. You don't need UV coating with them, and scratch resistance is a waste of money. It's that same material used in lab and safety glasses. I wear them as my regular glasses and recommend them.

Subject: RE: BS: Scratches in Glasses Question???
From: catspaw49
Date: 24 May 06 - 10:13 PM

Susan brings up Lens Doctor....I think it may be worth a try as you have absolutely nothing to lose at this point! ALSO HERE..where we all saw it first along with 531,936 other stupid ass ideas.....Although I did get a fine copy of 101 Polka Hits by Myron Kopetz and the Nose Flute Kings.

Spaw

Subject: RE: BS: Scratches in Glasses Question???
From: catspaw49
Date: 24 May 06 - 10:14 PM

BTW.....You're an idiot. Khandu is off the hook.

Spaw

Subject: RE: BS: Scratches in Glasses Question???
From: wysiwyg
Date: 24 May 06 - 10:15 PM

Yeah, Lens Doctor, that's the one.

If you have polycarb AND a coating, maybe all you scratched was the coating. ASK THE OPTICIAN before doing anyting, OK?

~S~

Subject: RE: BS: Scratches in Glasses Question???
From: wysiwyg
Date: 24 May 06 - 10:21 PM

PS, I assume P-Vine is reading this to you, Blind Bobert. Turn your face sideways so she can give you a kiss on the cheek from me, and then FALL DOWN ON YOUR KNEES AND WORSHIP HER for she is truly a saint.

(P-Vine, in case you don't know, all-caps is shouting, so give it to him REAL GOOD!)

~Susan

Subject: RE: BS: Scratches in Glasses Question???
From: Bobert
Date: 24 May 06 - 10:56 PM

Hey, first of all, the P-Vine has allready read me the riot act about not cleanin one's glasses witha 3M pad...

Second of all, yer welcome, khannydu, fir gettin' yer butt out of first palce as the world's largest idiot... Notm oo sure how that happened as I weigh in at 'bout 170...

But, most importantly, hey, if nutyhin' works to fix the glasses I can now blame them fir my crappy typin'....

That's my most recent story and, as per usual, I'll stick with it as long as it holds water...

Blind Bobert

Subject: RE: BS: Scratches in Glasses Question???
From: JohnInKansas
Date: 24 May 06 - 11:45 PM

The advice to get the advice of an optician is probably best. To remove the scratches you must remove part of the lens material, and it's unlikely you'll be able to do that without changing the shape of the lens surface, which will change the way the lens focuses and will make everything out of focus instead of just foggy.

If your optical supplier can remove the scratches, and if it can be done inexpensively, then you know what to do.

If the frames are in good shape, an optical shop should be able to fit new lenses to them, whether they're "out of style" or the latest thing. It's worth considering whether the frames will remain in good shape until you're due to replace the new lenses when you make the decision whether to get only lens replacements.

If it's been more than a few months since you had your prescription checked, an update examination is probably in order before purchasing a new set of glasses.

It's unlikely, although not impossible, that using the weedwhacker actually caused your scratches. It's much more likely that the scratches are from your "cleaning" after "whacking." Of course it's essential that you clean properly after you've whacked, but the emphasis must be on "properly." All of the plastics used for lenses now are "scratchable." The polycarbonate are much more resistant, but not immune, to scratches.

Any abrasive cleanser is dangerous to use on lenses. Many common household cleansers will actually "dissolve" the surface lens material and can cause fogging. Even "wiping off the dust" without moistening the lens may eventually cause enough small scratches to "fog" the lenses.

Note that "safety glasses" or safety lenses in standard style frames usually are made of the same polycarbonate that you can (and in my opinion should) insist on having in your "everyday" glasses, and are no more resistant to scratching or fogging than ordinary lenses. The "safety" part of it is that they'll resist breaking when hit by large flying objects. When doing anything that might scratch your regular lens, you should probably also use a throwaway pair of "safety goggles" to protect even your "safety lenses" when there's a "scratch hazard."

John

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 25 May 06 - 02:32 AM

Polycarbonate lenses are thinner and lighter than glass, and the poly is very strong, thus ideal for resisting impact. The best for active kids. People prefer poly glasses for their thin look and shapes that keep up with changing styles. Also, if one has a strong prescription, their light weight makes for easier wearing.

Glass is MUCH more resistant to scratching and is preferable for the careless person who cleans his lenses with paper towels and dishwasher liquid or has a tendency to put his glasses on stone or tile counter tops, etc. Glass lenses provide the clearest vision, and are preferable for those doing close, precision work.

Now Bobert is a problem. He sounds like a lens-scratcher, so glass will keep its clarity longer. On the other hand, he obviously needs the safety of polycarbonate since he engages in dangerous activities.

Lens polishing by an optician may remove cloudiness and the very fine scratches, but of course no more than that. I referred earlier to professional cleaning and repolish.

Coating adds some resistance to polycarbonate, but will never meet the scratch resistance of glass.

Subject: RE: BS: Scratches in Glasses Question???
From: JennieG
Date: 25 May 06 - 03:12 AM

Happened to me last year Bobert.....the scratched lens that is, not the manner in which it happened! I went to the optician, had my eyes tested again (wasn't quite due for it but what the heck) and got new specs. Nice ones with fine dark blue frames (coz they didn't have dark green).

I have now learnt not to drop my glasses on concrete steps.

Cheers
JennieG

Subject: RE: BS: Scratches in Glasses Question???
From: The Fooles Troupe
Date: 25 May 06 - 04:43 AM

Remember Bobert, to clean properly after whacking, next time... :-)

Subject: RE: BS: Scratches in Glasses Question???
From: Bobert
Date: 25 May 06 - 08:46 AM

Ahhhhhhh, thank's fooles-t.... Some lesson ya' got to keep relearnin'...

Subject: RE: BS: Scratches in Glasses Question???
From: JohnInKansas
Date: 25 May 06 - 10:02 AM

Q -

It's rather difficult now to get "real glass" in eyeglasses in the US. I belive it still can be done, and glass has advantages for some people. Except in "optical aids" such as loupes and such, most lenses that are easily available probably will be plastic.

Several kinds of plastics are used, mainly because the plastics can be easily molded instead of spending hours grinding and polishing as with glass.

I haven't kept up on any recent changes in new plastics for lenses, but I believe a common material for plastics was in the polymethylmethacrylate family. The name may be off a bit, but these materials have high refractive index, great clarity, and allow making very lightweight lenses, especially when a large amount of correction is needed. They are, however, relatively soft, and usually are offered with scratch-resistant coatings. The last time I tried them, the anti-scratch coatings helped some, but they were still not as resistant to scratching, with the coatings, as the harder materials were without one. (That was several years ago (actually "decades" ago) so newer coatings may be available now.)

The polycarbonate lenses often are slightly heavier for the same amount of correction, but have good hardness and "toughness," so this material is generally used for "safety" glasses. If properly processessed, the polycarbonate lenses are quite hard, and scratch-resistant coatings are not generally needed or of any benefit. Unless something's changed since I last dug into the details, it would be rare to find an anti-scratch coating offered with polycarbonate lenses.

Since most eyeglass sellers use lens blanks from one or the other mass manufacturers, and since a trade-name can be ™ or © while the material name is already probably ®, many of the eyeglass sellers don't appear to know the chemical name/class of what they're using. They just use the sales literature that the lens manufacturer gives them, including the "lens name™" that the mfr tells them to. For the user, if an eyeglass provider offers an anti-scratch coating, it's probably safe to assume their material is a soft one; and I go look for a seller who doesn't suggest that it's needed - who probably is using polycarbonate. It can be hard for most consumers to determine what actually is being used though.

Especially in eyeglasses, it often is a compromise between the best durability and best optical properties. The available optical plastics are supposedly good enough optically that I'm told that some very good camera lenses now use mostly plastic lens elements.

John

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 25 May 06 - 10:22 AM

"That's my most recent story and, as per usual, I'll stick with it as long as it holds water..."

At your age you can hold water? Right. Tell us another one . . .

Subject: RE: BS: Scratches in Glasses Question???
From: John MacKenzie
Date: 25 May 06 - 11:36 AM

You can get HRI quartz lenses in glass. If you are a rich recording star, with another CD to make.
I suggest
'A Scratchin' and A Whackin'
for the next title.
Or maybe 'Making a Spectacle of Himself in the Weeds'.

Giok

Subject: RE: BS: Scratches in Glasses Question???
From: Ebbie
Date: 25 May 06 - 03:07 PM

"when Bobert cranked the trimmer back up it snatched his glasses from his head and spun them through the weeds at about 1600 RPM which resulted in the scratched lenses. "BeeDub

What an image! LOL

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 25 May 06 - 05:54 PM

Right, John, a lot of eyeglass shops sell only plastic, and don't have an optician trained to do glass properly, but your opthamologist will direct you. Most people don't need them. When I was working I was chained to a microscope and other instruments of torture, and I was rebuilding (or trying to) watches as a hobby, so stuck with glass. We had some polycarbonate glasses without correction we used when we went to the shops where there was a chance of flying fragments, etc.   

Don't sucker for the latest frame styles for plastic eyewear which can be very expensive and give the shop uberprofit on uberstyle. Übercool! This is perhaps the main reason the fitter doesn't like to talk glass. Be sure to specify impact-resistant polycarbonate; some of the other plastics now being used are even more scratch-prone.

Subject: RE: BS: Scratches in Glasses Question???
From: Amos
Date: 25 May 06 - 11:26 PM

Ya mighta known that this would be a topic of wide spread and intense interest indeed, most of us bein' of an age and all...

A

Subject: RE: BS: Scratches in Glasses Question???
From: The Fooles Troupe
Date: 26 May 06 - 08:17 AM

... and if you take the insects out of the glasses before draining them, they won't get scratched either...

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 26 May 06 - 11:40 AM

Bobert's world thru the glasses--post weed whacking.

. . . with the lenses fixed . . . .

Subject: RE: BS: Scratches in Glasses Question???
From: JohnInKansas
Date: 26 May 06 - 01:07 PM

So Peace, you're saying it doesn't make much difference?

John

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 26 May 06 - 01:10 PM

I luv him, butchaknow . . . . Blues singers--whatcha gonna do?

Subject: RE: BS: Scratches in Glasses Question???
From: Donuel
Date: 27 May 06 - 12:15 PM

Been there done that.
Lenscrafters will refuse to polish lenses.
They will clean them but will not polish.
The only solution I have found after many hours of tedious polising labor is to buy glass lenses in the first place.

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 27 May 06 - 08:53 PM

The answer is to get new eyes.

Well, almost. I had the lens of one eyeball replaced yesterday, the other one will be junked and replaced this fall. Cateract surgery. Didn't want to mention it here until I felt that I would recover.
The doctor said it will take a couple of days to adjust, and to wear an eye cover at night for 2-3 days, and to take the drops he prescribed for a couple of weeks, and to come in in a couple of weeks to see if he made any mistakes, and to quit crying over junking the expensive trifocals he had prescribed only six months before. They gave me some green goggles to wear home and wear for a day or two outside. There will be follow-up tests later.
I am test-driving the new lens now and quite a difference. I have cut the brightness on the tv and monitor screens in the house. The other eye is following along like a wounded duck. It will be late fall before I get the other lens replaced. The replacements seem to be much better than they were a few years ago and there is almost no recovery time now- My wife had it done 3-4 years ago, and she had to use a patch for a few days.
The old model natural lens in my other eye (worse than 20-40)) is not only fuzzy, but the focus is different. He said let the new lens do the leading. After a week or so try out the different reading glasses I have collected- the least correction that helps with the vision in the untreated eye. He said it may be a few days before I get used to reading with the new lens.

Looks like I made the right decision, though. My eyes are getting tired so I had better stop until tomorow.

Spyware is popping up its cookie Guard notice, it seems like every few seconds. What is Mudcat trying to do?

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 27 May 06 - 09:00 PM

Just checked and it is IE, trying to set up valueclick.com and adviva.net. No idea what these are.

Subject: RE: BS: Scratches in Glasses Question???
From: wysiwyg
Date: 27 May 06 - 09:51 PM

Bobird has gone strangely silent......

~S~

Subject: RE: BS: Scratches in Glasses Question???
From: Bobert
Date: 27 May 06 - 11:16 PM

Okay, I used the P-Vine's silver polish tonight and now I'm less blinder than I was but better than before... Gonna have to buy some lenses, thou....

BTW, WySuzie, "Strangely silent" beats strangely vocal which is my usual M.O....

Jus' too buzy to keep up wid everythin'...

Blind Bobert

Subject: RE: BS: Scratches in Glasses Question???
From: John MacKenzie
Date: 28 May 06 - 04:57 AM

You could write a song called 'There ain't no more White Canes on the Brazos', and change your name to 'Tappin' Along the Sidewalk Bob'
Giok
(I'm in trouble now!)

Subject: RE: BS: Scratches in Glasses Question???
From: The Fooles Troupe
Date: 28 May 06 - 07:22 AM

And remember Bobert, no more whacking in future with your glasses on, or something similar was the moral...

oh, sorry, you don't want morals...



No, wait a minute....

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 29 May 06 - 08:01 PM

Recovering from lens replacement not quite as easy as I thought. Some slight soreness or what feels like slight pressure. Some sensitivity to bright light- should disappear in 4-5 days as the eye gets used to the addition. Also peripheral vision will improve back to normal in a day or two. Two sets of eyedrops, one antibiotic. Haven't driven yet. They say not to get any new readers until the final OK is given. I have appointments with the technical staff for tests starting about ten days from now.   

The cateract operation is paid for by the Province but waits are long . They only paid a small portion of the cost of prescription glasses. Don't know just what other eye problems beyond cateracts are helped by the lens replacement.

Subject: RE: BS: Scratches in Glasses Question???
From: GUEST,jOhn
Date: 30 May 06 - 07:34 AM

I got my glasses from Specsavers, they are rubbish, i payed 10 pound more fore special non scratch glass, but it still sctratched, i reckon i was ripped off, fiddling basterds.

Subject: RE: BS: Scratches in Glasses Question???
From: Helen
Date: 30 May 06 - 05:11 PM

Q, there's a short story by Daphne du Maurier called The Blue Lenses about a woman who wakes up in hospital after getting eye surgery. It's sort of a fantasy story. But very relevant to your current circumstances. Worth a read, and a giggle, when you are up to it.

Helen

Subject: RE: BS: Scratches in Glasses Question???
From: The Fooles Troupe
Date: 30 May 06 - 07:50 PM

Bobert,

Have you ever thought about getting some Rose Coloured Glasses?

Subject: RE: BS: Scratches in Glasses Question???
From: Bobert
Date: 08 Jun 06 - 08:13 PM

Well, yeah, rose colored glasses was big in tghe late 60's... I had a pair but...

...firget that!!!

First of all, nuthin' that nayone suggested worked... I tried silver polish, Brasso, minerial; spirits, acetone and just plain rubbin' but them lenses was nmessed up so...

... las' Thursday I took my seriously messed up glasses to some optical place in Harrisonburg, Va. and they made me new lenses, which I got today, an' I am back to beiong a memeber of the "sighted" population...

Hooray...

See how welkl I type an' speel, now???

Boberz

Subject: RE: BS: Scratches in Glasses Question???
From: number 6
Date: 08 Jun 06 - 09:11 PM

"nuthin' that nayone suggested worked" ... didja take the advice given in this thread about going out and getting new glasses?

sIx

Subject: RE: BS: Scratches in Glasses Question???
From: Al
Date: 09 Jun 06 - 01:38 AM

The reason polycarbonate lenses are highly impact resistant is that they will bend rather than break. And, they are very soft and scratch easily. All polycarbonate lenses come with a scratch resistant coating on the front. A scouring pad will scratch any type of lens. Scratches cannot be polished out without destroying the optics. Just get new lenses.
Al

Subject: RE: BS: Scratches in Glasses Question???
From: Al
Date: 09 Jun 06 - 12:47 PM

To clarify my previous post, all ophthalmic polycarbonate lenses come standard with a scratch resistant coating. Non Rx lenses probably do not.

Subject: RE: BS: Scratches in Glasses Question???
From: GUEST,Rufus
Date: 09 Jun 06 - 12:53 PM

Leave em scratched Bob. Maybe even go over them a couple more times so youre even more out of touch wit realety.

Subject: RE: BS: Scratches in Glasses Question???
From: Bobert
Date: 09 Jun 06 - 01:45 PM

LOL, Rufe...

Actually, I would love to get away from some of my realities which at present have me stretched a tad on the thin side.... But, gotta make a livin'...

Subject: RE: BS: Scratches in Glasses Question???
From: JohnInKansas
Date: 09 Jun 06 - 02:21 PM

Al -

Your experience with carbonate lenses differs from mine.

The majority of plastic lenses sold in my area are acrylic, NOT carbonate. They are very light weight and have good clarity, but they are softer and scratch rather easily. They nearly always should have a scratch resistant coating, which quite often is a thin layer of polycarbonate.

Optical polycarbonate is quite hard and is reasonably scratch resistant. Without going to "exotic" materials, there are no coatings that will improve the scratch resistance of a good quality carbonate lens, and if a seller is offering a "scratch resistant" coating he's probably selling acrylic lenses and not carbonate. (The few "exotic" coatings available are - or were recently - rather expensive, and give only marginal improvement in scratch resistance.) Good carbonate lenses don't need an additional scratch resistant coating for most users.

(If you get an anti-glare or uv coating on carbonate lenses, the coating may not be really tough, and an anti-scratch coating to protect some other coating might be recommended, even with carbonate lenses; but it should not be separately indicated on the bill.)

For most users, the carbonate lenses will be noticably heavier than acrylics, although not quite as heavy as "real glass."

Carbonate lenses are used in "safety glasses" and "safety lenses" can be very heavy, compared to ordinary glasses. To be considered "safety glasses" in the US they must bear the appropriate certification etched on the edge of the lens. If the cert markings aren't there, even good carbonate lenses should not be expected to provide eye protection if you're doing something where it's needed.

John

Subject: RE: BS: Scratches in Glasses Question???
From: Al
Date: 10 Jun 06 - 12:04 AM

Regular glasses lenses are made of a material marketed as CR-39. I'm not sure if that means acrylic or not. They are more scratch resistant and less shatter proof than polycarbonate. They are frequently coated for more scratch resistance on both sides of the lens. The optics of polycarbonate are inferior to CR-39 especially away from the optical center, and especially so in strong lenses. Polycarbonate lens blanks come from the manufacturer coated on the front surface for scratch resistance. The back surface of the blank is machined by the optical lab, and therefore has no coating. I could be wrong on the coating thing, but this is my understanding based on 26 years in the optometry business.
Al

Subject: RE: BS: Scratches in Glasses Question???
From: Q (Frank Staplin)
Date: 10 Jun 06 - 12:33 AM

CR-39 is allyldiglycol carbonate, according to the patent (4594288).
"Lenses of allyl-N-ethylene glycol carbonate having enhanced resistance to scratching or abrasion can be formed by preparing a substrate of a polymer or copolymer of allyl-N-ethylene glycol carbonate, the substrate being at least partially polymerized. A thin film of a copolymer of allyl-N-ethylene glycol carbonate and of an allyl monomer is formed by overmolding on the substrate and polymerized."
(Well, didn't you want to know?)

Acrylic eyeglasses seem to be made mostly in China. Many colors and designs, reading glasses, etc. Lenscrafters 'FeatherWates' seem to be made of acrylic. Couldn't find anything authoritative on types or use in prescription glasses.

Subject: RE: BS: Scratches in Glasses Question???
From: JohnInKansas
Date: 10 Jun 06 - 01:22 AM

Al -

I guess I should be glad to find that I'm not too old to learn a bit of new stuff.

As Q reports, Product Information: PPG CR39 reveals that CR39 is a "CR-39 allyl diglycol carbonate monomer," so previous information I received from suppliers, that it was an acrylic, was incorrect. This brief page is careful to distinguish this carbonate from polycarbonate that is, I think, what suppliers I've talked to who refer to their lenses as "carbonate" or "polycarbonate" are talking about.

"Lenses from CR-39 monomer give less chromatic aberration as measured by Abbe number than polycarbonate lenses."

At the left of the page there's a link to "other materials" that may be of interest. The "Product Bulletins" are all .pdf, but the MSDS sheets are html. There are several references to "polycarbonate" being an inferior material, but nothing to say what "polycarbonate" actually is. Apparently PPG doesn't sell it.

Possibly also of peripheral interest: PPG Optical Products History gets a short (107 KB) history, indicating that PPG is the patent holder for CR-39, and it's been around since 1940. This is well before the appearance of "polycarbonates" so far as I know, but I haven't been able to confirm that.

In addition to the misinformation on their "acrylic" lenses, I have to suspect that the competitors who offered polycarbonate lenses were similarly uninformed. I haven't found any good properties on optical polycarbonates, but advertising seems to indicate that it's customary to always apply a hard coating, when the lens blanks are produced, so since the vendors don't get to charge extra for it they didn't know it was there(?).

More research to do...., but the CR39 "name" was really helpful getting to better info than I was able to find the last time I searched.

John

Subject: RE: BS: Scratches in Glasses Question???
From: DougR
Date: 10 Jun 06 - 02:43 PM

Don't rub your eyes, Bobert. You COULD scratch your eyeballs too! Go to the nearest Wallgreen's (or whatever) drugstore and buy a pair of Dr. Dean Edell's glasses. You probably can replace your currently scratched glasses with a good pair of $14.95 variety.

DougR

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 10 Jun 06 - 02:49 PM

Did you hear about the optometrist who fell into his lens grinder and made a spectacle of himself?

Subject: RE: BS: Scratches in Glasses Question???
From: Al
Date: 10 Jun 06 - 05:12 PM

yes.

Subject: RE: BS: Scratches in Glasses Question???
From: Peace
Date: 10 Jun 06 - 05:14 PM

OK. Did you hear about the tree surgeon who fell twenty feet from one of his patients?

Subject: RE: BS: Scratches in Glasses Question???
From: bobad
Date: 10 Jun 06 - 06:44 PM

How about the butcher who backed into his meat grinder and got a little behind in his orders.

Subject: RE: BS: Scratches in Glasses Question???
From: The Fooles Troupe
Date: 10 Jun 06 - 06:48 PM

At least now, all his probelms are behind him.