I Are posh varifocals a ripoff?

sophiecentaur

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Why should the 'posh' varifocal lenses cost so much more to produce than the budget lenses?
When you decide to use varifocal lenses you are offered a range of three or four different 'qualities'. There will be differences in hardness, finish and coatings but what is the difference in the way the surfaces are calculated and ground? I once had some entry level varifocals and the vertical sweet corridor was so narrow that I needed to move my neck all the time to get things in focus. A have also had pairs that are much much better but which cost vastly more. I am stuck with the expensive ones now, of course.
What beats me is that they are all produced individually - unlike the run of the mill, single prescription lenses which involve choosing from an existing range of pre-ground circular lenses, with combinations of spherical and cylindrical radii. But varifocals (I assume) need to be calculated and ground (moulded?) individually. What is it about the best ones that makes them expensive to produce? I feel that it's just a commercial ploy to get more money from the public (why am I surprised?).

I would love to know from anyone who has some knowledge of the market and the technology about how it all works. I bet there is some specialist knowledge out there.

The quality of dispensing and fitting is very variable; I have had a pair with the totally wrong inter pupil distance and also with the cylindrical component at the wrong angle. When I bounced the ones with the wrong IPD (which I identified at the fitting), the fitter asked "how can you tell"??
Terrible situation when you think that people are wearing these things all their waking hours. The public can be so accepting in some matters and specs are a major cost to some people. It makes me wonder why so many people just "don't get on with them". I suspect that they often just get given the wrong prescription.
 

gleem

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Summary: Why should the 'posh' varifocal lenses cost so much more to produce than the budget lenses?

I once had some entry level varifocals and the vertical sweet corridor was so narrow that I needed to move my neck all the time to get things in focus.
Same here. I could not read a line in a book without moving my head. Since then I have reverted to standard bifocal or trifocal lenses.
 
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Summary: Why should the 'posh' varifocal lenses cost so much more to produce than the budget lenses?

I once had some entry level varifocals and the vertical sweet corridor was so narrow that I needed to move my neck all the time to get things in focus.
My previous lenses were varifocals. That head bobbing and neck wiggling became so obnoxious that this pair are just straight bifocals. No neck wobbling, I test up and test down and use the better of the two.
 

sophiecentaur

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Same here. I could not read a line in a book without moving my head. Since then I have reverted to standard bifocal or trifocal lenses.
My previous lenses were varifocals. That head bobbing and neck wiggling became so obnoxious that this pair are just straight bifocals. No neck wobbling, I test up and test down and use the better of the two.
I remember, with the cheap ones, I had to look directly at people to see who they were. Strangers would look very disturbed when I looked at them 'full face'; they knew I was observing them. (Creepy guy!!!!) Now I can be normally furtive and not offend anyone.

I suspect that you both didn't go for the most expensive ones. Mine are really pretty good and I have quite a wide region where things are ok at all distances. My only gripe is that they were very pricey and I can't see any excuse.
The first ones I had gave me wild distortions initially. Looking at a rectangular table top made it look diamond shaped and, in general, perspective was a new experience. Within a day, my brain had re-calibrated and, even with a series different prescriptions, the geometry is just fine.
 

gleem

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I suspect that you both didn't go for the most expensive ones.

They didn't seem cheap at the time 20 years ago. Had no other issues than with reading lines longer than about 3 inches or trying to scan a page for a term. You know what was a killer. dropping something small and trying to find it. You had to be pretty close and looking at it directly to find it.
 

sophiecentaur

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They didn't seem cheap at the time 20 years ago.
Oh no.I didn't say they were cheap. They were just cheaper than the expensive ones. From what you say about poor field, they were not top of the range. Finding things is not an issue with mine. I have a problem with binoculars because the sweet spots don't always coincide with the axes of the two tubes and that can be annoying. But I am very fussy about acuity and I always demand that the prescription I end up with will take me right down to the bottom line of the chart and sharp.
But this chat, interesting though it is as always, doesn't get to my real question about what they actually do that's different about posh ones if it's just down to geometry.
 
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I suspect that you both didn't go for the most expensive ones.
Yes, you suspect correctly! Although I also did not go for the least expensive ones either. I usually feel that the best value avoids both extremes.
 

sophiecentaur

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Yes, you suspect correctly! Although I also did not go for the least expensive ones either. I usually feel that the best value avoids both extremes.
Unfortunately for me, the high cost actually produces better results and, as I wear them all the time, I at least get the benefits all of my waking hours.
But I want a member of the Opticians' Profession to give me a good answer. I may have to wait some while.
 
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the high cost actually produces better results
I was so aggravated by the annoying feel of the midrange version that I abandoned the product line entirely with no intention of going back. I will just use bifocals instead.
 

gleem

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Unfortunately for me, the high cost actually produces better results and, as I wear them all the time, I at least get the benefits all of my waking hours.
Doesn't this answer your question "are they worth it"? Could they be cheaper? I bet they could. I suppose you could try the medium priced one but is current satisfaction worth the possibility of inferior performance worth the money saved?

Oh no.I didn't say they were cheap. They were just cheaper than the expensive ones. From what you say about poor field, they were not top of the range.
In my first experience with progressive lenses, as they were once known, I was not given a choice of prices. As far as I know there was only one option except for various coatings.
 

sophiecentaur

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I will just use bifocals instead.
I tried bifocals when I was teaching but there was a real drawback. When wandering around the classroom, looking over the kids' shoulders, the long option meant that I couldn't read their work and the short option was so short that I had to lean right over them, making them uncomfortable. So varifocals were just right - just overpriced.

Doesn't this answer your question "are they worth it"? Could they be cheaper? I bet they could. I suppose you could try the medium priced one but is current satisfaction worth the possibility of inferior performance worth the money saved?
The best ones are pretty good - but that doesn't stop me from complaining, does it??? I won't go back to the slightly naff ones.
 

Andy Resnick

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Summary: Why should the 'posh' varifocal lenses cost so much more to produce than the budget lenses?
My most recent glasses (the ones on my face right now) are varifocals- I wanted to try them since I now need bifocals and won't be caught dead wearing 'old people' glasses. My (optical) prescription also corrects for astigmatism.

You are basically correct that varifocals (freeform lenses) are more difficult to manufacture, and cost only increases by addressing the fundamental trade-off of using a single element to perform the entire optical correction. Off-axis optical aberrations quickly grow to obscene levels are require fancy surface figures to even partially correct. Grinding/fine-figuring the element is more expensive than just casting a mold, and custom grinding/shaping more expensive still.


In the end, I'm not happy with my varifocals- my far-distance correction is 'pretty good', but not good enough for astrophotography. Similarly, the field of view that is sufficiently corrected is smaller than I would like. I'm going back to 'regular' glasses next time. Unfortunately I can't wear contact lenses anymore (because of my need for bifocals.... grumble, grumble)
 

Dr Transport

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I agree with Andy, I had varifocals years ago and went back to regular glasses. I have astigmatism correction and only need them for up-close (reading and computer) work. For the most part I wear my glasses all the time and look over the top for distance and raise my head slightly for computer work.

Getting old is a b****, my prescription went form +1.5 to +2.75 in a year, I said something to my wife about it and she said my eyes were tired. I responded, it's like that in the morning when I get up, can't be too tired. At this rate, I'll be legally blind up close in about 5 years. My distance vision is still 20/20 and up until about 2 years ago it was better than 20/20 (maybe that's why I was such a good marksman in the service, I could see whings well at distance).
 

sophiecentaur

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My most recent glasses (the ones on my face right now) are varifocals- I wanted to try them since I now need bifocals and won't be caught dead wearing 'old people' glasses. My (optical) prescription also corrects for astigmatism.

You are basically correct that varifocals (freeform lenses) are more difficult to manufacture, and cost only increases by addressing the fundamental trade-off of using a single element to perform the entire optical correction. Off-axis optical aberrations quickly grow to obscene levels are require fancy surface figures to even partially correct. Grinding/fine-figuring the element is more expensive than just casting a mold, and custom grinding/shaping more expensive still.


In the end, I'm not happy with my varifocals- my far-distance correction is 'pretty good', but not good enough for astrophotography. Similarly, the field of view that is sufficiently corrected is smaller than I would like. I'm going back to 'regular' glasses next time. Unfortunately I can't wear contact lenses anymore (because of my need for bifocals.... grumble, grumble)
The second link was very informative and makes sense too. Thanks it was what I was looking for. It does bring up the question of how the dispensing optician (the woman who puts your chosen frames on your nose and takes a few perfunctory measurements) can give the manufacturer enough information to get the lens that's best suited to your eyes / face. It strikes me that they need to know where your pupil is relative to the lens and how it actually moves as you scan a scene; it will move at least 10mm from side to side around the radius of your eyeball. That must affect the width of the corridor. They seem not to do anything about that - not even measuring the distance from pupil to lens. That can vary from person to person, according to face and chosen frame. "Near enough for Jazz" is ok when you're spending, say £30 but the top lenses cost £100+ (plus coatings etc.). A few seconds of extra measurement is not too much to ask. I will be choosing some new specs at the weekend as my left eye is getting worse so I will have to get ready to be ripped off yet again.

I actually get on with the best quality specs quite well (when they are 'right) and it's a shame that yours aren't satisfactory. I found that putting my eye at a repeatable place for focus on a telescope with varifocals can be difficult. I tried an additional fixed focus pair for telescope use but that clashes with the need to look at equipment close up. Perhaps a reading prescription would be best all round; after all, there's no reason to have a scope presenting an image at infinity. An image at reading distance would be fine (as long as you can still identify the main stars in the sky, for alignment.

Yes; old gimmer's bifocals are a no no!!

Maybe hi res 3D printing could be the answer before too long.
 

PAllen

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In the end, I'm not happy with my varifocals- my far-distance correction is 'pretty good', but not good enough for astrophotography. Similarly, the field of view that is sufficiently corrected is smaller than I would like. I'm going back to 'regular' glasses next time. Unfortunately I can't wear contact lenses anymore (because of my need for bifocals.... grumble, grumble)
There is another way, that allows contact usage. I am well along in years, and adopted the following strategy once my near correction stabilized around +2.5/2.75. I invested in super top of the line varifocals neutral on top, and with stable reading correction towards bottom. These NEVER need to change, so a high one time price is fine. Then, variations in prescription over a few years are all in the contact lens. The varifocals are over 15 years old and still fine. If you can't stand any varifocals, then use bifocals or trifocals instead. Point is, for all outdoor activities, all driving, etc. I use contacts as I always did. Indoors only, I put on the over contact correction. I find only indoors do I need frequent shift from near to far focus.
 

PAllen

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There is another way, that allows contact usage. I am well along in years, and adopted the following strategy once my near correction stabilized around +2.5/2.75. I invested in super top of the line varifocals neutral on top, and with stable reading correction towards bottom. These NEVER need to change, so a high one time price is fine. Then, variations in prescription over a few years are all in the contact lens. The varifocals are over 15 years old and still fine. If you can't stand any varifocals, then use bifocals or trifocals instead. Point is, for all outdoor activities, all driving, etc. I use contacts as I always did. Indoors only, I put on the over contact correction. I find only indoors do I need frequent shift from near to far focus.
I guess it helps if you are not a cell phone addict - then you will always need shift to close focus. I often go one one to two weeks without turning on my cell, having it with me only for emergency outcalls.
 

sophiecentaur

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I often go one one to two weeks without turning on my cell, having it with me only for emergency outcalls.
Does that mean that there is no one who might like your help in an 'emergency' of theirs?
 

PAllen

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Does that mean that there is no one who might like your help in an 'emergency' of theirs?
I instruct everyone to contact by email or landline, which are checked regularly, but not while I am hiking, looking at exhibits, etc. I simply do not want to be connected when I am outside [until 2 years ago, I refused to take my cell phone on solo hikes, but finally my wife wore me down on this point; but she still accepts that she can't call me unless it is prearranged, because my phone will be off]. So someone may need to wait some hours before I get a message. So be it. Of course, if there is any prearranged expectation of need to coordinate, or known urgent issue potentially developing, then I'll keep my phone on.
 

sophiecentaur

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@PAllen
Wow - that's organisation for you. I could never manage to impose such rules on my family. Sometimes they 'just need me'. I could never foresee when that could happen.

I love your contacts + reading varifocals solution. Ideal for someone who can cope with contacts.
 

PAllen

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Wow - that's organisation for you. I could never manage to impose such rules on my family. Sometimes they 'just need me'. I could never foresee when that could happen.

I love your contacts + reading varifocals solution. Ideal for someone who can cope with contacts.
Well my wife is similar in philosophy, just a little less extreme. We know of no one who got cell phones later than we did. Neither of us routinely give out our cell #, and if we do, we say you’ll go directly to voicemail if you call it at a random time. We have cell plans optimal for our philosophy - we each pay about $10 a month for all charges related to our cells.

As for my wife “needing me” rather than wanting me, that’s a bit of a joke - she was a well established professional in the same field as me, owning and managing her own property, with degrees in math and economics, when we met.
 

Tom.G

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my prescription went form +1.5 to +2.75 in a year, I said something to my wife about it and she said my eyes were tired. I responded, it's like that in the morning when I get up, can't be too tired. At this rate, I'll be legally blind up close in about 5 years. My distance vision is still 20/20
For those that aren't aware of the reason behind this.
Focusing is done with muscles that change the curvature of the lens. The lenses get stiff with age and won't bend for close focusing... hence the need for 'Reading Glasses', which are sold over-the-counter here in the USA with no prescription needed.

Addendum:
I tried Varifocals, once. There was no place in the lenses, or distances, that I could see as well as I did with trifocals. I do have a somewhat unusual prescription though, astigmatism varies dramatically with pupil opening. This makes the needed astigmatism correction different for daytime and and nighttime. The compromise was make the distance grind for nighttime use so I could locate the oncoming traffic better. The intermediate grind is corrected for daytime use, when there are enough other distance cues for me to figure out how far away that oncoming truck is.
 
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sophiecentaur

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We know of no one who got cell phones later than we did.
Do you have a plain 'phone or a smart phone? It would be a shame if you have a smart phone but if you miss out on the thrills and spills of PF when you are on the move. I could be writing this on a sunny mountain top or out at sea, for instance. Double whammy!
There was no place in the lenses, or distances, that I could see as well as I did with trifocals.
I would wonder about the quality of the freeform grinding (the main point of my OP), the width of the 'corridor' and the fitting of the lenses to your face so that the sweet spots coincide. I have had at least one pair where the lenses were centred wrong.

You are probably right about correcting strong astigmatism being an added problem in designing the lenses. Personally, I found the transition between the two regions of bifocals was at least as objectionable as any nasties of the best of my varifocals.

The brain is truly wonderful in totally correcting for lunatic geometrical distortions that varifocals introduce.
 

PAllen

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Do you have a plain 'phone or a smart phone? It would be a shame if you have a smart phone but if you miss out on the thrills and spills of PF when you are on the move. I could be writing this on a sunny mountain top or out at sea, for instance. Double whammy!
We have moderate priced android smart phones. I only went to a smart phone in the last year.
 

PAllen

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I agree with Andy, I had varifocals years ago and went back to regular glasses. I have astigmatism correction and only need them for up-close (reading and computer) work. For the most part I wear my glasses all the time and look over the top for distance and raise my head slightly for computer work.

Getting old is a b****, my prescription went form +1.5 to +2.75 in a year, I said something to my wife about it and she said my eyes were tired. I responded, it's like that in the morning when I get up, can't be too tired. At this rate, I'll be legally blind up close in about 5 years. My distance vision is still 20/20 and up until about 2 years ago it was better than 20/20 (maybe that's why I was such a good marksman in the service, I could see whings well at distance).
Actually, your near correction will probably not change anymore. You’ve reached the point where you are doing no near focusing anymore, so there is nothing to get worse.
 

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