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MrPin

Glasses Made Of Glass?

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Is it possible to get glass spectacle lenses any more? :huh:

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Why would you want them?

Don't scratch so easy. Handy when you wipe them with a gritty glove, after a long motorcycle ride!

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Glass is still used for some very high index lenses, but plastic is cheaper and lighter so is used in most cases.

The original plastic lenses were crap. I think they are better and tougher now! I always used to insist on glass, but I'm not offered it any more. It's only a small prescription for driving. The last time I had "proper" glass must be 1980s.

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Is it possible to get glass spectacle lenses any more? :huh:

You can get them if you ask for them.

Glass should be cheaper than (decent) plastic, but it is a bit more niche these days so glass might be similar (or even more expensive) where you are. But glass is more likely to break, so even with a cheaper up front cost glass might cost more over the long term.

Glass is probably superior to plastic in every way apart from weight and durability. But weight and durability are probably the most important aspects for spectacles, so plastic nearly always wins for most people these days. If you've got a high prescription then the weight issue will really dominate, for low prescription the additional weight of glass won't be such an issue.

There is also the aesthetic - glass needs a proper frame.

Not sure I'd ride my motorbike with glass spectacles - driving okay though.

If you go to a proper old-fashioned opticians then they'll go through this sort of thing with you in your consultation - if they don't, bring it up!

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You can get them if you ask for them.

Glass should be cheaper than (decent) plastic, but it is a bit more niche these days so glass might be similar (or even more expensive) where you are. But glass is more likely to break, so even with a cheaper up front cost glass might cost more over the long term.

Glass is probably superior to plastic in every way apart from weight and durability. But weight and durability are probably the most important aspects for spectacles, so plastic nearly always wins for most people these days. If you've got a high prescription then the weight issue will really dominate, for low prescription the additional weight of glass won't be such an issue.

There is also the aesthetic - glass needs a proper frame.

Not sure I'd ride my motorbike with glass spectacles - driving okay though.

If you go to a proper old-fashioned opticians then they'll go through this sort of thing with you in your consultation - if they don't, bring it up!

Not at all. I had glass rimless ones for the Himmler look! :blink:

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Don't scratch so easy. Handy when you wipe them with a gritty glove, after a long motorcycle ride!

I found daily disposable contact lenses best for the motorcycle.

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Is it possible to get glass spectacle lenses any more? :huh:

Yes. I have them in mine.

Being blind as a bat I need high refractive index material otherwise the lenses are too thick, so that rules out plastic. Unfortunately it costs a fortune (we're talking the best part of a grand). However that's only for the special high index stuff, I imagine ordinary glass doesn't cost so much.

And it's true they don't scratch as easily as plastic, on the other hand they shatter a lot more easily...

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I actually posted a thread on this very topic/question not so long ago.....

The answer, as others have already said here, is yes - at special request and at extra cost.

That extra cost, on top of the whole rip off cost of having to use any sort of corrective lenses for ones vision, got me to the point of exploring what other options there are.

I then discovered the (now seemingly falling out of favour commercially?) non-surgical procedure of Conductive Keratoplasty (CK).

I say "non-surgical" because it involves no cutting/removing of any corneal tissue AND does not involve making any modification to the cornea over the surface where light enters the eye.

For someone like me, with mild (but irritating) long sight AND mild astigmatism too, I am told the treatment would be eminently suitable.

There is a question mark over the longevity of the treatment though. It is openly stated that the cure it provides (i.e restoring perfect specs free vision) diminishes with time, over several years. BUT the big question is whether that is because most people being treated are those whose vision/prescription deterioration has not yet settled down to fixed value - and their eyes are still going through the aging process.

IF the treatment is applied to someone whose vision is no longer deteriorating, and no longer needs to get ever stronger reading glasses, then they would be the best candidates - and the treatment would presumably last a sufficiently long time to so make real savings in the need for periodic replacement glasses (lost or broken, etc)

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I actually posted a thread on this very topic/question not so long ago.....

The answer, as others have already said here, is yes - at special request and at extra cost.

That extra cost, on top of the whole rip off cost of having to use any sort of corrective lenses for ones vision, got me to the point of exploring what other options there are.

I then discovered the (now seemingly falling out of favour commercially?) non-surgical procedure of Conductive Keratoplasty (CK).

I say "non-surgical" because it involves no cutting/removing of any corneal tissue AND does not involve making any modification to the cornea over the surface where light enters the eye.

For someone like me, with mild (but irritating) long sight AND mild astigmatism too, I am told the treatment would be eminently suitable.

There is a question mark over the longevity of the treatment though. It is openly stated that the cure it provides (i.e restoring perfect specs free vision) diminishes with time, over several years. BUT the big question is whether that is because most people being treated are those whose vision/prescription deterioration has not yet settled down to fixed value - and their eyes are still going through the aging process.

IF the treatment is applied to someone whose vision is no longer deteriorating, and no longer needs to get ever stronger reading glasses, then they would be the best candidates - and the treatment would presumably last a sufficiently long time to so make real savings in the need for periodic replacement glasses (lost or broken, etc)

Hmm.

CK is still a drastic procedure for the eye - it might not be ablating away layers of cornea but it doesn't mean that it isn't having a significant effect on the eye. IIRC there are permanent effects even if the effect on refractive error isn't permanent. It is probably safe enough but there aren't any 60 year olds who had the procedure 40 years ago yet*...

It doesn't really have that good results - post-op 90% have vision 6/12 or better - not that good really (6/10 is about the driving standard, but of course you can still use correction to get to that - but what is the point if you still need the spectacles...). And it isn't even a stable result - so as the eyes drift back to where they were before you'll find that none of your glasses work particularly well.

Also, like photorefractive surgery there is an effect on vision - starbursts/halo etc. When you have the post-op tests they'll measure eye performance with the lights turned up high - this gives you a nice small pupil so better vision anyway, but also the smaller pupil receives less light through the peripheral cornea (the bit that you just mucked about with) so you only see through the central bit of the cornea (not mucked about with). When you go out and about in the dark later you'll have a nice large pupil and will be using the peripheral cornea... Quite a few people find the effects annoying. They can be a bit of a problem with night driving, as well.

[to be fair, these days they often do measure post-op performance with a in low light / low contrast - but even so, the 'hey this is great' test is always done in brightly lit conditions].

And CK seems to favour over-correcting for presbyopia - where you set the furthest focus distance to the middle distance. I find that anyone puts up with this very surprising indeed - and again, for things like driving you'll need (or should use) glasses with this, eliminating some of the benefit.

They also do CK with monovision - where they correct one eye for distance and the other for near. IMO anyone who regards the results as acceptable are suffering from cognitive dissonance (only my opinion, and I've not had it done myself so what do I know...).

If you are mildly long sighted and middle-aged I guess it can only harm your wallet... I'd probably not have it done, but there are worse things you can do to your eyes**.

If you're looking at alternatives, also investigate orthokeratology. It works okay for mild long-sightedness and isn't permanent. Like CK it is more likely to harm your wallet than your eyes. Once upon a time some people were quite keen on this - photorefractive surgery more-or-less killed it's market, though. Again, I'd probably not bother**.

*eg, we're now seeing the long term effects of radial keratotomy done in the 1980s.

**don't pay too much attention to this - I'm notoriously anti- 'surgical' correction for mild refractive error (well, if you knew me you'd know I was notorious). I push the 'hotel room fire' test - where if you can't make your own way out of an unfamiliar building in an emergency without your glasses then you would likely be a good candidate for photorefractive surgery. I'm also very suspicious of any procedure pushed at early presbyopia, particularly with mild hyperopia - these people are very easy to sell to. Anyway, do a bit of research and make up your own mind.

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Hmm.

CK is still a drastic procedure for the eye - it might not be ablating away layers of cornea but it doesn't mean that it isn't having a significant effect on the eye. IIRC there are permanent effects even if the effect on refractive error isn't permanent. It is probably safe enough but there aren't any 60 year olds who had the procedure 40 years ago yet*...

It doesn't really have that good results - post-op 90% have vision 6/12 or better - not that good really (6/10 is about the driving standard, but of course you can still use correction to get to that - but what is the point if you still need the spectacles...). And it isn't even a stable result - so as the eyes drift back to where they were before you'll find that none of your glasses work particularly well.

Also, like photorefractive surgery there is an effect on vision - starbursts/halo etc. When you have the post-op tests they'll measure eye performance with the lights turned up high - this gives you a nice small pupil so better vision anyway, but also the smaller pupil receives less light through the peripheral cornea (the bit that you just mucked about with) so you only see through the central bit of the cornea (not mucked about with). When you go out and about in the dark later you'll have a nice large pupil and will be using the peripheral cornea... Quite a few people find the effects annoying. They can be a bit of a problem with night driving, as well.

[to be fair, these days they often do measure post-op performance with a in low light / low contrast - but even so, the 'hey this is great' test is always done in brightly lit conditions].

And CK seems to favour over-correcting for presbyopia - where you set the furthest focus distance to the middle distance. I find that anyone puts up with this very surprising indeed - and again, for things like driving you'll need (or should use) glasses with this, eliminating some of the benefit.

They also do CK with monovision - where they correct one eye for distance and the other for near. IMO anyone who regards the results as acceptable are suffering from cognitive dissonance (only my opinion, and I've not had it done myself so what do I know...).

If you are mildly long sighted and middle-aged I guess it can only harm your wallet... I'd probably not have it done, but there are worse things you can do to your eyes**.

If you're looking at alternatives, also investigate orthokeratology. It works okay for mild long-sightedness and isn't permanent. Like CK it is more likely to harm your wallet than your eyes. Once upon a time some people were quite keen on this - photorefractive surgery more-or-less killed it's market, though. Again, I'd probably not bother**.

*eg, we're now seeing the long term effects of radial keratotomy done in the 1980s.

**don't pay too much attention to this - I'm notoriously anti- 'surgical' correction for mild refractive error (well, if you knew me you'd know I was notorious). I push the 'hotel room fire' test - where if you can't make your own way out of an unfamiliar building in an emergency without your glasses then you would likely be a good candidate for photorefractive surgery. I'm also very suspicious of any procedure pushed at early presbyopia, particularly with mild hyperopia - these people are very easy to sell to. Anyway, do a bit of research and make up your own mind.

Thanks indeed for this!

I'm fully aware that CK is not, and to be fair is not claimed to be, anywhere near as effective/accurate as the 'surgical' LASIK type treatments.

BUT....I was not aware of CK also carrying a risk of LASIK type side effects such as starburst/halos! I assumed that these would, except for extreme minority, would be absent - precisely because to no cutting of tissue is involved and also because the corneal surface covering the light path is not interfered with.

Do you have any links referring to said side effects?

Also you seem to imply that the treatment (steepening of the corneal curvature) is actually physically non-permanent (i.e the cornea gradually reverts to its original 'defective' shape) - and not just because the patients prescription continues to worsen post treatment (i.e the eye/lens has not finished the aging process)

The cost of CK has now come down dramatically, from what I can see (pun intended!). To the point where IF the treatment longevity was at least 5 years then it would probably equate to the amount I would spend on specs/contacts/etc - and even IF it were still a wee bit more expensive it would still mean being spec/contacts free.

What I find personally irritating is not so much the need to wear specs for close work/reading but that my distance vision is degraded more by the astigmatism. IF there were no astigmatism I could get by with just cheapie reader specs from the high street chemist for sub-arms length distances. My vision might not be perfect (i.e. stars in the night sky would not appear as nice pin sharp points of light) but I would be able to read a number plate as per driving test standards.

So my looking at CK as an option is more a lifestyle choice rather than a 'need'.

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BUT....I was not aware of CK also carrying a risk of LASIK type side effects such as starburst/halos! I assumed that these would, except for extreme minority, would be absent - precisely because to no cutting of tissue is involved and also because the corneal surface covering the light path is not interfered with.

Do you have any links referring to said side effects?

You'd expect some effects just because the cornea now has a complex curvature - you can only increase the curvature in the central bit by flattening out the bits to the periphery - so with a wide open pupil you get well focussed light from the middle and poorly focussed light from the periphery - which you'll see as halo.

You'll see references to these effects in things like http://www.refractec.com/docs/pdf/CKforPresby.1year.Stahl.pdf, http://www.researchgate.net/profile/Marguerite_Mcdonald2/publication/8267701_Treatment_of_presbyopia_with_conductive_keratoplasty_six-month_results_of_the_1-year_United_States_FDA_clinical_trial/links/09e4150c244af7d4da000000.pdf

Also you seem to imply that the treatment (steepening of the corneal curvature) is actually physically non-permanent (i.e the cornea gradually reverts to its original 'defective' shape) - and not just because the patients prescription continues to worsen post treatment (i.e the eye/lens has not finished the aging process)

There is a slow return towards the pre-op state over years.

The cost of CK has now come down dramatically, from what I can see (pun intended!). To the point where IF the treatment longevity was at least 5 years then it would probably equate to the amount I would spend on specs/contacts/etc - and even IF it were still a wee bit more expensive it would still mean being spec/contacts free.

What I find personally irritating is not so much the need to wear specs for close work/reading but that my distance vision is degraded more by the astigmatism. IF there were no astigmatism I could get by with just cheapie reader specs from the high street chemist for sub-arms length distances. My vision might not be perfect (i.e. stars in the night sky would not appear as nice pin sharp points of light) but I would be able to read a number plate as per driving test standards.

So my looking at CK as an option is more a lifestyle choice rather than a 'need'.

OK. As I said I'm generally anti this sort of thing, but that is just me.

Very much a personal thing - nothing is perfectly safe, contacts have risks (maybe the risk from contacts is greater than any risks from CK) and there are even risks from glasses (eg, gets a bit fogged up and you miss something, say).

So long as you don't expect it to cure your presbyopia and you go in with your eyes open...

(but I would avoid monovision)

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Had PRK 21 & 22 year's ago for short sightedness (prescription = -2.5, -3.5).

Final prescription = 0, -0.5 has remained fairly stable but now, at 53, starting to need glasses for some close up work.

I also wear glasses for driving, just to give me a slight correction of the -0.5.

Generally, being out and about and in the office, I get on fine without glasses.

Whichever technique is used, I think there is a fundamental issue re the practicalities of carrying out the operation. For access/simplicity, the operation has to be carried on the front of the eye, whereas the majority of the defect (too long an eyeball in the case of short sightedness) has arisen from excess growth at the back of the eye (or so I believe).

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