Why Do Progressive Lenses Have Distortion at The Sides?
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- čas přidán 28. 06. 2024
- A tough question to answer simply, but one an optician should be able to explain. Let's dig into the optics of progressive lens design to see if we can come up with a good explanation as to why there must be peripheral distortion (aberration) in any progressive lens.
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Fundamental of Progressive Lens Design by Darrel Meister
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Just got my first pair of progressive lenses and was looking for an explanation of how they worked and what they should look like. Your video was excellent and answered all my questions! Thank you for doing this; it's invaluable info to have accessible for all of us, professionals and laymen alike!
I’ve been waiting for this “simplified” explanation for so long, thank you John
hi everyone ,if anyone else is searching for i hate progressive lenses try Scarlazzina Exemplary Genie (do a search on google ) ? It is a good one off guide for finding the secret for natural eyesight improvement minus the hard work. Ive heard some awesome things about it and my work buddy at last got great success with it.
I realize I am kinda off topic but do anybody know a good site to watch newly released series online?
@Emerson Chaim Meh try Flixportal. you can find it through google :) -cairo
@Cairo Joel Thanks, signed up and it seems like a nice service :D I really appreciate it!
@Emerson Chaim You are welcome =)
Always wondered, why there is distortion, and you gave the best and clearest explanation possible :-)
I'm here again, learning...thank you...
You ARE A LEGEND! Much love from London, uk!!
Much love back!
CRICKEY!!! This was a great video and we use it to explain distortion to our patients. Thanks for an amazing video John!
Excellent explanation, John!
Thanks! That is one of my all time favorites. Funny - most of my all time favorites were the hardest ones to do. Keith, the K in Laramy-K, the physics guy, deserves as much or more credit for making these work than I do. I have a little optician brain and we go back and forth, and back and forth, and back and forth until it is both scientifically/mathematically correct yet presented at the optician level of understanding. John
Great video !
I loved this explanation, especially the play-doh example. I once had a shower thought that play-doh would be a good way to explain lens design to my staff and this video proves I was not completely wrong about that.
Great minds think alike!
You provide information very efficiently and you are great to listen to.
Thank you for the content
Thank you for a plato explanation. I feel I get it now
Thanks for great information 🌹❤
This is a good video. I needed to listen to it.
Love your videos
what a beautiful explanation. this is art. everyone who comes to progressives always wants to know why cant we have progressives all the way from edge to edge and top to bottom with out those medial and lateral geographic distortion areas, or why do we have them there in the first place. well ladies and gentlemen this video is the answer right here.
Thanks! That is among my all time favorites. I just kick myself every time I watch it for not placing the green play-doh cylinder on both sides. I also know I could never go back and do better so I leave well enough alone. John
Brilliantly explained!
Thanks - that is among my favorites that we have ever done. John
@@LaramyKOptical I'm here as my new progressives have a massive amount of distortion in the intermediate zone which my current ones do not. I reckon a different lab or model within the lab as the differences are shocking. I don't know the old lenses type but the new one is Shamir Sprectum Plus. I have spent over three months and two sets of them and still can't adapt to them ☹️. The height of the new lenses to fit the frame is a fair bit more and so is the thickness of the lenses at the edges if that matters any?
@@skylineuk1485 Yep - sounds like you don't like the design of the new lens. It is possible (90% of the time) using the Progressive Lens ID (available online) to figure out what that old lens was. Probably want to get as close to that design as you can. Bigger frame = thicker lens but that shouldn't matter if lens is set correctly - assuming no power changes or minimal power changes.
@@LaramyKOptical Thank you!
I’ve had dizziness for a while now wonder if it’s my progressive lenses ?
Harlan Ellison taught me it is actually, "You can't EAT your cake and HAVE IT too," which make so much more sense. Even when I was five, I knew you could have your cake...and then eat it, which confuses the entire point of the saying. (But you can't EAT your cake, and then HAVE IT too...because you ate it.)
@Chandler Castiel Better pro tip: Flixzone is a complete scam used to steal your credit card number. Don't believe me? There is an entire thread on reddit about it. The pattern is the post the above comment, and then if someone replies to it, a second comment (from a different account name) automatically pops up saying they have used it and it is safe. IT IS NOT. Both accounts will be blank and have been created in the last few days.
This is really helpful information. Thank you. Makes me think that in some lenses the cylinder was never meant to provide any vision correction, it is just a form of filler.
In my case, I have scleral lenses on the way. I asked for those contacts to provide only midrange support. Then I will have glasses over the contacts for distance. The scleral lenses are new for me. But the glasses over midrange contacts aren't. I have gotten used to keeping my glasses on a strap (Cabelz) so I can take them off temporarily and be hands free. Enter the idea of progressives. I am hoping that the minimal transition between negative (-1.0) and positive (+1 or as small as possible) power will minimize the peripheral cylinder distortion. What do you think?
Sorry, way too much going on here for me to answer. Sounds like you have a contact lens person to work with, hopefully you can find an optician to help you 1:1. John
Thank you sir
Do you have any lesson fir Digital progressive lens, thank you so much fir all your informative classes.
czcams.com/video/je0cq8zV54Y/video.html
Really helpful John, thanks. It definitely is a all about the C word isn't it ? - COMPROMISE...
Larry
My prescription changed. Im now at 2t add. I cant stand the blurry peripheral vision. My balance is off. Horrible. Im thinking of going back to trifocals. Whats your thoughts on trifocals. I would rather see better than than worry about looks at this point.
Thank you so much
If you have had a true traditional lined trifocal before - sure go back to them. If not then I'd lean heavily towards a traditional bi-focal with the lightest add you can tolerate. That should give you what you need to get around. After that go with different single-vision pairs for different needs. Progressives are great but they aren't for everyone. John
What a great explanation 👍
LOVE these videos! I'm starting Optician school in January 2020 and I look forward to incorporating more of your videos into my studying/learning!
Join www.OpticianWorks.com.
@@LaramyKOptical I did take a look at the site! Clear and informative! I'm from SK Canada though so I am taking the program through NAIT :) Still going to visit the CZcams channel for more info though!
@@foodistheloveofmylife Lots and lots of Canadian opticianry students use the site. In fact a few of the instructors use the videos in their classrooms. John
@@foodistheloveofmylife Well, if you like the videos --- when you get stuck on a concept in the NAIT program you might find OpticianWorks will be the answer. Optics is optics and opticianry is opticianry...
For work in an office on a computer, how do office progressives compare to good old bifocals with near and intermediate only?
If that is what you are using now just stick with them. Better and much, much cheaper too.
I want to know ..why near vision in a panorama design are getting curved while following downside?
What are your opinions on trifocals? I’ve worn progressives for years and recently my vision changed; my prescription worsened. I tried the the varilux brand progressives and was close to impossible to see through. Now I’m in a trifocal and can’t see through them comfortably either! What can I do, get three
Pair of glasses?
YES! You will find an intermediate pair will get you through a heck of a lot indoors. Distance only outdoors... Then any task specific distances. Like we say over, over and over, "...maybe progressives aren't the answer for everything."
@@LaramyKOptical thanks for the reply. so trifocals aren’t the answer either!?
@@l.c.1633 Probably not the "perfect" answer. A little tricky to find and a little tricky to fit too. Certainly worth a try if you can find someone willing to work with you on it. Should be able to do a "test" pair for not a lot out of pocket.
I was prescribed progressive lens 3 weeks ago after decades of wearing single lens for distance which I only wear to drive or activities like zoo trips or hiking. My eyes are very different, one far and one near so to read or do inside work I must take my glasses off to see.
The problem comes when shopping, for example, since I need my glasses to see which aisle but take them off to read labels. That I can handle, but I do landscaping. Tree work I easier with my glasses until I do close up work. Taking glasses off and on is frustrating at work. But I can't get used to the tunnel vision. I need all peripheral vision I can get. When I tree is coming down, watching for deer on the road at night, or my evil rooster sneaking up to attack, progressive just aren't working.
What should I do? Go back to just single lens and readers for sewing? I also quilt. Do they still make those little half glasses you can peek over the top of?
Do what I do! Old fashioned lined bifocal with a slightly weak add. Nothing in the way of great distance vision with good peripheral and intermediate/near when you need it. With one eye near/one eye distance you might need to play around with add powers a little. Find a good independent optician with some patience and you should make out great. OH and yes SV "readers" for sewing/quilting.
Yes, just go to lined bi or tri-focals. The trees really don't care that they can see you're no longer 18, I promise it will be OK. ;-) The problem I see (har har) is that opticians (at least the ones I have seen) just assume that everyone is vain and wants progressives. I have to wonder, were you even ASKED if you wanted one over the other? Told the advantages/downsides of each and given a choice? My guess is no. Progressives seem to be a win of marketing to vanity over actual excellence in vision correction. Anyway, I've tried progressives twice, rather far apart in time, once at the urging of the optometrist and once much later just to try again. Each time I was clawing them off my face and begging for the lined lenses back. If your priority, like mine, is actually SEEING pretty much like normal and not having to swivel your head to read a line on a computer screen at normal distance when your eyes track outside the microscopic point of focus and the text starts to smear, or to have to swivel your head to read street signs while driving (MUCH more problematic), get lined bifocals. Plus, they're much cheaper. And about the quilting, fellow quilter here! :) My sewing machine is behind me as I sit at my computer. I had glasses made with my computer distance up top, and my reader distance in the bottom. Perfect. Having a couple of pairs of purpose-built glasses (one for outside, one for computer/sewing) is also more affordable if you aren't buying progressives, which as we know from the video, don't do anything WELL. I want my glasses to really WORK, not just be...eh, good enough, you know?
John do you do optical CE speech? Please let me know, I’m Susan.
Is the varilux X series the best?
NO! The best is any free-form designed lens that is fit properly, matched to your needs and run by a company that knows their equipment. A Varilux whatever is just another lens and may well be one out of 10,000 run that shift. Brand names and marketing BS don't matter. John
I've only watched 2 of your videos. I'm a consumer, not a professional. I would love to know if you think there is any optical advantage to contact lenses over progressives. For intermediate and distance vision I get a much clearer sense of peripheral vision with them, but I suspect you're going to say that otherwise they're inferior. Thanks in advance for any thoughts you may have. Best, Bill
Goodness no! If contacts work well for you then they are the way to go. Really no substitute for many sports. Thing is eventually you will have to carry some drug-store cheaters around but heck that's not so bad. Now, don't get me started on "bi-focal" contacts... that is another thing all together and "inferior" is a nice way of putting it. John
@@LaramyKOptical Oh!. Actually I should have said I was talking about "multi-focal" contacts. So I'm back to thinking about glasses. There's an independent optometrist that I like who is set up at the local Costco. A couple of years ago Costco set up their own manufacturing facility. If I skip progressives, do you think I'm OK getting 3 pairs of glasses from there? One for distance, one for reading, and one bifocal? He's got no axe to grind on having me buy at Costco.
Just reread my own response and wanted to clarify that you've talked me out of getting progressives at all. I'm a very active 72 year old, but I don't need to worry about looking old fashioned with bifocals, and I think I can adjust to having 2 pair of glasses with me most of the time. For those times when it's annoying, then I can fall back on the bifocals. I do have an astigmatism. But my prescription is still
relatively mild. So first, do the 3 pairs make sense? And for at least the single vision glasses, am I OK with the moderate Costco prices if I've got a good optometrist writing the prescription. He's not crazy about progressives wears bifocals himself. So your videos have explained to me why he's not crazy about the progressives. Sorry to be so long-winded. You're a great guy.
@@MagicSamaritan I'd never admit to it on some kind of public forum like CZcams or anything but (for many reasons) I too wear an old fashioned lined bi-focal. I just like the distinct zones and the wide distance vision. Of course I also have something like 5 pairs of intermediate-near around the house.
@@LaramyKOptical Any thoughts about getting single vision glasses from Costco?
Sir why did Daryl uses plus cylinder lens to blend ?
I wouldn't call it a plus cylinder lens. I would call it plus cylinder filler. That is still all based on positive base curves and minus back curves for both sphere and cylinder. And remember all that is conceptual not an actual lens design.
I just had cataract surgery so my prescription went from a -7.5 to a +2.5 and I just received new prescription computer glasses. I was hoping that because my prescription is much simpler now the progressive lenses wouldn't be so distorted. I was very wrong! These new ones have an extremely limited field of view - even more than my older -7.5 glasses. What I don't understand is why the $35 progressive reading glasses I bought from Amazon are dramatically better for field of view?! I find myself using them more than my $200 prescription glasses.
Lucky you! if the power is +2.50 in each eye you can go over-the counter for everything. Just buy one of those multi-packs from Costco with different powers and play around to find the perfect one for all the different things you do. If you do one thing that you love for extended periods of time then consider having a really nice pair made up in that power. John
Im a big fan of you
Thanks, so much, Mehdi!
I am 52 age . I use progressive lenses . Spend 6 hours daily on screen & two hours reading . Should I go for separate single number lense to reduce Fatigue?
I can't make that decision for you certainly not without a lot more information - BUT - if a single vision pair or pairs is an option you can't go wrong! Much more comfortable for the long haul... John
I've worn glass bifocals (plain and Photogrey extra) for decades. Glass bifocals do not have that "ledge". I was surprised when I ordered a tinted non-glass pair to discover the ledge. I was told, like in your video, that ot was impossible to not have a ledge in a bifocal. Why is there no ledge in glass, but always in plastic?
A plastic bifocal area gets its power from increased curvature, hence a ledge. A glass bifocal area gets it power from increased material index literally melted into the blank, hence, no ledge.
@@LaramyKOptical Thank you so much for clearing the mystery. I prefer the elegant glass solution over the industrial one. The bummer for me is recent cataract surgery from a lifelong -5+. My eyes are now both -2.25, cyl +0.50 & +0.75 with add +2.25. That equals a plano bifocal or a progressive with muddy areas. Or distance only. I mentioned the possibility of a short corridor progressive to my optician and was told it was an old technology that I wouldn't like.
@@akahina I'd say keep watching some of the other videos on progressives. I'm not sure why a short-corridor would be desirable - in fact that would increase the likelihood of distortion or "muddy areas." That plano bifocal wouldn't be plano since it would provide the mild cylinder corrections of .50 and .75. Heck - how is your near vision when you take your glasses off?
@@LaramyKOptical My vision is fine from about 18" to my fingertips.
I wonder if this still stands with the new tech of zeiss progressive lenses
Ain't no magic pixie dust! A progressive lens will always have problems.
It is just not clear why someone doesn’t make a progressive that leaves the whole top (distance) area in focus and makes the necessary adjustments (cylinder) BELOW.
Why does the entire lens have to be messed up leaving maybe just a few degrees of clear vision in the middle?! That deficiency creates danger for any kind of travel from walking to driving.
Because the Chinese suppliers are Lazy and Profit oriented. Got to feed that CCP Glut!
Eye doctors are trying to turn as much profit as possible, At the cost of YOUR Eyes in some cases.
Day two of progressives.
To what extent does your brain compensate over time? Will I always feel a bit drunk and sick? Will I always notice things bending?
Also, I'm a tall person and seem to have to lean my head over to get focus for counter height tasks or looking down when standing or walking. This seems bad for posture.
Two days of fairly constant wear should overcome any issues. Drunk, sick, bending objects, excessive head movement are all red-flag items in my book. I'd have them mark-up the lenses and ask to see them on and look where things line up. It all begins with the question, "Relaxed, level headed, looking straight ahead are things clear in the distance?" If they are things usually fall into place. If they are not then you have a problem. Being "very tall" can create issues. Like I keep saying ---- progressives are not the answer to everything.
did u keep them?
I'm going through the same crap and the Eye place laughs it off.
I'm not understanding the whole cylinder thing. 🤷🏻♀️
Why didn't anyone tell me this before I bit into the thought they were "better" than line in bifocals? This is what everyone said. I hated bifocals, not because of the line but because I couldn't get use to them. So, just got my progressives, and feel drunk. I only have a small spot to read. Who reads by moving their heads vs their eyes. I will probably just get a distance pair and a reading pair in the future. Big waste of money!
You have the wrong optician? ;-) John
Lay it at the victims feet, eh?@@LaramyKOptical
@@LaramyKOpticalis having to pair glasses one for distance and one for reading better then the trouble of progressive lens especially if you have Menieres which can cause vertigo?
3 places that you can find that
I always thought it WAS an easy answer; because a progressive lens is not edge to edge...the rx is not in the whole lens. I usually draw a picture to explain the lack of rx on the outside edges of the lens. Is this not correct?
Yes, but the question is, "WHY is it not edge to edge?" That's what this video tries to answer.
I've got Porche SUV, that I can take on a racetrack - or off road - no compromises.
"...no compromises." LMAO
How are lens such as Nikon, Zeiss, or Seiko able to get wider progressive corridor?
You answered your own question. "wider" Not wide, not across the lens just a little wider. It doesn't matter the brand name or the marketing BS. The free-form software will push the corridor width out to as wide as it can go FOR A GIVEN LENS POWER. Depending on the design (what distance the lens favors) the free-form software will adjust the corridor shape FOR A GIVEN LENS POWER. The more you ask of a progressive the narrow the corridor width will be. John
I didn't ask for cake. I expected the optician to understand what I need based on what I want most out of glasses. I didn't ask for progressive, it was recommended for first time prescription wearer. So to vanity, compromise, you should add, opticians bias and failure to understand.
We have another video where we keep repeating over and over... "Maybe, just maybe, progressives aren't the answer to everything." And, "Just because they are very expensive doesn't mean they are something special."
@@LaramyKOptical clearly you ate dedicated
Haha, what an accent!!!!!
As a customer....i think your honesty is refreshing because the multifocal is CRAP. Too bad the optometrists arent as honest.
However i understand their dilemma. customers need help seeing clearly...however there isnt a product that can fix nearsightedness and presbyopia so one can see clearly....so in an effort to help their customers they wont reslly say....your old now..so i dont think you can fix that, Too bad.
Well "crap" might be a little harsh... lots and lots of folks wearing them with good results. But not for everyone. John
@@LaramyKOptical Thank you for the reply. I have a problem with the distortion because I play golf frequently and believe me...it impacts my game....I am now trying single focus for distance during golf, and still are keeping my multi focus for other tasks. Is it common to use a different lense with different demands with multifocus and distance?. I am having a problem accommodating my changing eyes and their ability to make me see clearly enough to drive, etc. Your correct about compromise in the world of optics.
@@chooselife903 czcams.com/video/uR5L0aUejVc/video.html
There is no “distortion” in most progressive lenses
For goodness sake give it a rest Barry. If the term was good enough for Darryl it was good enough for me.
Porsche makes SUVs that are sports cars.....poor analogy on your part.
(Your play-doh is not helpful at all, btw). So, I'm confused. Are you perpetuating the fallacy pushed by the eyeglass industry or are you saying otherwise?
9:45 You say "the ledge has to be there," referring to executive trifocals. You say the optical aberration has to be there for progressive lenses. And yet.........I can buy, and have bought, and currently own, "off-the-shelf" progressive reading glasses exactly like executive (Franklin) trifocals with temple-to-nose correction, with NO ledge, NO corridor, NO optical aberration, NO distortion. If I am reading fine print, I look through the bottom portion of the lens (2.00 magnification) the whole way left to right, without having to move my head to stay in the asinine corridor because there is no corridor. If something is a bit further away, I may raise my eyes a bit and I get 1.75 magnification the whole way across left to right, if I am looking at my computer screen, I look through the center of the lens (1.50) left to right the whole way across, etc., etc., 1.25, 1.00. .75 up to the top of the lens for distance where there is virtually no magnification. No headache, no dizziness, no disorientation, no need to adapt to them.
At least two companies have sold these. "ICU" used to market these as "Omni-Focus" and Foster Grant still sells them as "Multi-Focus" progressive reading glasses. The magnification strength is constant left to right (nose to temple) for the full width of the lens, with the gradation occurring in parallel fashion from the bottom of the lens to the top. They can be ordered online for $35 in strengths from 1.25 on up. Occasionally they can be found in drugstores, Target, Walmart, etc.
So, can you/will you make progressive reading glasses like I have now - full left to right (nose to temple as you call it), with gradations similar to executive lenses, without ledges, without corridors, without peripheral optical aberration/distortion?
Thanks.
Yes.
do your "off the shelf" PAL glasses come with cyl and axis correction?
@@kellz6266 I don't know. Your question sounds like you're an optician as it's a technical question - should I care? I googled sphere, cyl, and axis which didn't provide much enlightenment.
A bigger question I have is, are you saying that glasses such as I describe can actually be ordered? I have other issues going on with my eyes (nothing to do with anything glasses will address) so have seen at least five different types of ophthalmologists with various specialties, all of whom are capable of writing a script for glasses of course. None has ever even heard of the glasses I have. Same with every optician store I've been to as most seem to be just sales people pushing overpriced frames (most of which are controlled by the EssilorLuxottica monopoly) with standard progressive lenses, or default to pushing bifocals when I tell them progressives make me dizzy. They could provide a real service if they took an interest in addressing a person's needs - and expand their market!
Presumably my OTS glasses don't have that correction. All I know is I can see perfectly fine at any distance for reading, computer work, and various project work to about four or five feet, fully left to right and right to left. I do not need them for distance correction, although I can keep them on, for example, if driving (good for reading the dash gauges). As presbyopia has progressed over the years, I have simply increased the power of my OTS glasses. That said, it would be nice to have higher quality lenses, coatings, or other features.
Vanity is so selfish. Those who are over 40 now have to have blind spots in our glasses or be the outsiders. smh Sticking with my lined bifocals anyway.
Less and less people (by number of viewers and dates) is watching this shit.
What a great explanation 👍
John do you do optical CE speech? Please let me know, I’m Susan.
Assuming you mean ABO-CE's then no. If you are inviting me to speak at a conference in Hawaii all expenses paid with first-class airfare then yes. Email me please through the OpticianWorks website.
What a great explanation 👍
What a great explanation 👍