Choosing Lens Material Based on Lens Power

[@PMX]

Another thing that I found out the hard way since my optician failed to mention it: how sensitive is the person to chromatic aberration. I got polycarbonate lenses made since they were thinner and lighter... but the seller failed to mention (pretty sure wasn't even aware) the high chromatic aberration issues when looking off-center on a poly lens with high diopters (-4 myopia with -2 astigmatism). Had to replace those glasses.

[@TheHi-T]

I recommend Trivex. I switched from polycarbonate. Immediately noticed a better optical performance while playing sports. Suppose to be more impact resistant. I have a high prescription. Not all online companies have Trivex & will not allow me to order polycarbonate. ZENNI gives me the option to order what lens index & material I want. Optical clarity is my priority. Other companies insist I pay more for thinner lenses that has a lower optical performance. (Abbe value). No thanks.

[@danhule]

yeah when i mention it to them they seem like im insane for even noticing it.

[@flyguy6504l]

I have the same problem with polycarbonate, I get cr39.

[@envio82]

Lmao. I nearly fell over laughing at that fake chart. (Using my husbands you tube account here. I’m actually the wife writing. ) Anyway I thought that chart was for real and just frantically hoped it would be avail in a drop down menu or something and I cracked up when I saw the paper crumbled and tossed aside. I promise these are my favorite optician videos on earth. Lol. Great videos!!!! I wish that chart did exist!!!!!!!!!!!,

[@luisgomez1211]

Laramy K, I'm an Optician, for many years...( + 25 ) still I'm trying to learn something, and I did, very good explained...thank you...

[@jeffreyzeidner8182]

Simple way to choose lens material. Not counting the odd materials and in between indexes cr then poly 1.67 and finally 1.74 each is very close to 10% thinner than the next index. Calculate the thickness of cr and go from there. You can show the difference to a customer by using a caliper.

[@rxbristol]

I wear large frame glasses with -4 diopter and while their isn't much difference between 1.67 and 1.74 in the thickness of the lens, there is a significant difference in weight. I always opt for the 1.74 lens.

[@LaramyKOptical]

As the saying goes: "Your results may vary." But --- Our weight comparison. Which is a test I did myself on a scale for weighing grains of powder shows 1.74 as being heavier than 1.67. 4.71 g vs. 4.35 grams. Your results may vary - but we have done similar tests in the past and the results are the same. It also follows the "higher density = more weight" rule of thumb.

[@rxbristol]

Fascinating. Now that I'm due for new specs, I'm more concerned than ever over the quality of the lenses being offered. Especially now that I've moved to a different city away from an optician that I trusted and could work miracles on frame adjustments.

[@Nekoandpiano]

Hello! Thank you for the information. Can i ask is it OK then to use 1.60 for -6.25 /-6.75 ? I had to pair of glasses now with prescription 1D lower. One with index 1.67 and one with 1.60. And I love 1.60 more because higher ABBE and I'm kind of sensetive to it since I work as a graphic designer with a lot of bright contrast objects. In local eyeglasses shop they told me like 1.60 would very bad for prescription above 6, but it's kind of not a lot above...Thick lenses bothers me less then chromatic abberations. Thank you!

[@LaramyKOptical]

short answer = yes stick with 1.60, choose as small a frame as possible and go with a really good AR. long answer = watch this video again and then the other 14 that we mention! John

[@Nekoandpiano]

@@LaramyKOptical Thank you!

[@redgreenbeambih]

Then go 1.74 lol with an A-Spheric lens

[@erickcartman7104]

Could you talk about edger settings (bevel, groove,polishing ) please ? Thanks

[@LaramyKOptical]

There is already a video on bevel placement, the next one coming out is High Curve and Step Bevel. Drop me an email through the OpticianWorks website and we can sort the other stuff --- mostly comes down to button pushing these days. John

[@rohan5150]

Ahh the dinner plate special. I love this term. Unfortunately, I as a lab tech, deal with optical dispensers that only want to make the sale and not want to discuss with the client why that huge frame with a polarized lens (ie, 74mm frame pd and 55 mm pd) is not ideal for their -8.25 -2.25 rx.

[@LaramyKOptical]

Yeah, like I always say... "A (good) optician must learn how to say, no." Yep really hard on the lab folks. But, but 1.74 fixes everything!

[@rohan5150]

@@LaramyKOptical True, but unfortunately it was 1.60

[@LaramyKOptical]

@@rohan5150 Oops... Kidding about 1.74 "fixing everything." It might be a little bit better better choice and it might make for a slightly thinner edge but the "dinner plate special" will never be a good choice regardless of material. John

[@charleshorseman55]

The fact that you can roll through dozens of lenses for testing tells me I am wildly overpaying for glasses lenses.

[@LaramyKOptical]

Well, we are a wholesale optical lab that MAKES lenses and those are all basic designs in single-vision with no special coatings added. Not sure you are connecting the dots quite right. Yeah - glasses are pretty expensive but what isn't? John

[@glshim13]

Make sure when you talk to the lab, the person you are talking to is the lab technician. Our office talked to a customer service agent who had no clue what "backside base curve" meant and thought it still meant the "front side". Needless to say the lens we received came in super curved and once we talked to the technician, he understood right away that something was off and got the lenses we needed.

[@LaramyKOptical]

That certainly depends on the lab. I can assure you that the customer service people at Laramy-K know their lenses and optics. I think you have something like 140 years of combined experience in the department. If you call in the afternoon chances are quite good you would end up talking with Janet the President, CEO and a founder of the lab. That is the difference between a corporate lab and an independent one like Laramy-K. John

[@katec.4361]

🤔 Why is 1.74 quirky stuff? How does it compare to 1.67?

[@LaramyKOptical]

1.74 is very prone to aberration where 1.67 is far less so. 1.74 also poses some problems when being surfaced. As mentioned in the video save the 1.74 for the really high stuff in SV finished uncut jobs.

[@User24x]

What thickness number is the Poly? 1.57? Edit: It's called the"index" of the lenses, not "thickness number" (I didn't know what it was called before).

[@LaramyKOptical]

The index of poly is 1.586. You will see it rounded up for marketing nonsense. It is NOT a high-index lens. It is often one of the thinnest/lightest combinations but certainly NOT the thinnest lens material available. The term "thickness number" is incorrect and not anything from optics.

[@User24x]

@@LaramyKOptical Thanks for the info

[@cosmoguarriellojr7822]

I want to get a few glasses I want thick lenses, one high index, one glass and one trivex, what numbers do I need for thick lenses? I also want to get big black frames at a size 61-18-150 or 60-18-150

[@LaramyKOptical]

I'm sorry but I have no idea what you are asking and can't figure out why any one would want thick lenses. If this is a joke I guess I missed the punchline - sorry.

[@cosmoguarriellojr7822]

@@LaramyKOptical I'm not joking

[@MrLim26]

in singapore i did my specs they told me the lens need like 10 working days becos its done by the labs and with my power its 1.60-1.67. luckily isn't too thick -Jonathan

[@Nick-_-452]

Hi John, I just wanted to drop you a line and say that as a consumer, I've found your videos incredibly helpful. I recently was diagnosed (+1.75/+2) to need intermediate glasses in my 30s and have found that there are many different intricacies as well as options for everything optics. As an engineer by day, I had to take it upon myself to learn what the best option for my needs was since most local stores had uneducated sales staff that told me all of the chromatic aberration was in my head and wasn't real. I've dealt with 8 different local and chain opticians in the last two weeks and only one of them was able to get me the Zeiss or Hoya SV lenses I was looking for and the coatings I wanted. Only two of them could tell me the exact lenses they could order and three were able to order trivex. I had no idea how much informational gaps there were in modern glasses shops and I have a newfound appreciation for the local optometrist that everyone seems to love as well as our friends at Laramy-K!

[@LaramyKOptical]

Did you mean to type, "...newfound appreciation for the great optician I found on Laramy-K KZbin." ??? ;-) John

[@ikarugaxx3749]

""uneducated sales staff that told me all of the chromatic aberration was in my head and wasn't real." The issue is, optician is a work demanding wits, which still pays very little monetarily. The results of this contradiction are there for everyone to see.

[@MrLim26]

Hi Mr John i am very curious that some lens needed pre-orders especially some lenses aren't to be instock some also needed to wait estimated 2weeks can i have some explaination of this? thank you Jonathan i am from singapore

[@surendersingal2192]

Thank you sir, I admire your patience n gentle teaching technique. Your coverage is quite lot. Thank you sir.

[@dekjules32]

Thanks for your great content. Question - what would cause a significant, sudden, seemingly permanent change in vision from one day to the next with no trauma involved? Appreciate any insight you or an viewers can provide.

[@LaramyKOptical]

1,000,000 miles outside my wheelhouse... The 2nd Golden Rule of Opticianry is, "Never, ever, never diagnose." We leave that to the medical people. ;-) John

[@MartinNeep]

You used the word ‘significant’ which is concerning. Don’t take any chances! Get yourself a same day appointment with an optometrist, or failing that… go to the ED!

[@Killedbyncf]

Yea but now it's at the point (with lens B/O's) the big essilor labs are just telling us they don't know and to try to submit the order and see what happens, no dates, no eta's, also with safety frames! and they have them mostly, but they don't have the corresponding side shields so they can't send the safety frame. I do CSR at a BIG lab. It sucks telling the account that we don't know until about a day or 2 after they submit, especially insurance jobs.

[@LaramyKOptical]

Well, thanks Nate! There you go folks - straight from a BO CSR - Use Laramy-K!

[@adrianlira1821]

I've been out of the business for a while. This video was very helpful, and I can use it on my current job. Thanks

[@ikarugaxx3749]

I never leave such comments on KZbin or elsewhere, but, really, you are doing amazing work for all who want and can to benefit. I don't know why they pay opticians half or one-third the pay one gets employing his wits to do something else, that's the root of the problem of what we stumble upon when we go to buy our glasses & lenses.

[@LaramyKOptical]

Thank you so much for the kind words. I wish I could say differently but it is mostly the opticians and the few opticianry schools who are at fault for the low wages. They think/teach that by pretending to be in "healthcare" they will somehow elevate their status while ignoring the fact they are in business and if they thought that way they might actually get ahead. One of the reasons WE are teaching the consumers as much as the newbie opticians.

[@richardzamora9956]

Please cover glass as a lens material also.

[@LaramyKOptical]

You wouldn't choose glass by power for any reason. [Unless you are talking about a 1.8 high-index double grind sort of thing.] You would choose glass because someone has always worn it and likes it or they have a specific reason for wearing it like working around a specific chemical or they require the clarity of the optics. Glass was what we wore for a few hundred years - nothing wrong with it. It is (very) heavy and can get thick quite quickly as power goes up. Trivex and 1.6 will provide nearly as good optics with much less weight. 99% of the time glass will be one of those things that the customer will ask you about - not the other way around. On top of that (at least here in the US) very few labs even offer it anymore since demand is so low and raw blanks are getting scarce. John

[@richardzamora9956]

@@LaramyKOptical Thank you for your response John. The thing is that I sold a AR coated glass FT-28 yesterday to an older patient. From ocular history the patient cannot wear polycarbonate due to the low ABBE value. Where I work we only carry CR-39, Poly, and Glass. Since, poly was ruled out the two options left were CR-39 and glass. I explained the pros and cons of both materials. The patient decided on glass due to superior optics, superb scratch resistance, etc. There is an experienced optican that overheard the patients speaking about the glass material and he gasped at the fact that I sold the patient glass and began to ask the my patient if she wore glass before, etc. Basically causing doubt in the material. Though I value his opinion that plastic should of been the choice material he did not need to interfere in what we (patient and me) agreed upon. Do you think I made the wrong move? Also, what the optician did was not professional at all. If he wanted to coach me or voice an opinion he could of pulled me to side and spoken to me. Thanks again John.

[@LaramyKOptical]

@@richardzamora9956 You absolutely positively did nothing wrong at all. If glass is an option on your lens material menu and you choose to use it there is nothing wrong with it. The lab should assure it is properly tested for impact resistance and that is the end of it. Again - we all wore glass for a few hundred years. Most high-end proprietary sunglasses offer a glass option. I sold glass lenses to customers that had worn it and loved it - one fellow was in a HUGE 60+ eye with a progressive. He also ordered multiple pairs every other year - good customer, good money. In the future I wouldn't look down at CR-39 since it is another material that we all wore for 40 years when there was no other option besides glass. It isn't optically bad just thick and a bit heavy. So yeah tell your co-worker to mind their own business (in a nice way). And when those glasses lenses come it - put them in the lensmeter and see for yourself how much cleaner/sharper the lines and reticle is when compared to a plastic lens. Amazing! John

[@richardzamora9956]

@@LaramyKOptical Thank you John. Yes CR-39 is great but you can't beat glasses visual acuity!

[@charleshorseman55]

Is the assumption that there is no actual gain in thickness or clarity between standard cr39 and high-index for -4? Or is there a deficit in clarity? Thanks!

[@LaramyKOptical]

No, that isn't the assumption at all. Thickness change is negligible over poly and up certainly not down at the CR-39 end of the scale. Clarity comes down to many factors including Abbe which we have a video on.

[@R.C.Bullar]

Fantastic video! Really helped me. Cheers!

[@jsmariani4180]

This is good stuff. I would like to see a video comparing spherical to aspheric lenses in different materials.

[@LaramyKOptical]

I'm not sure why you would want to see that? If thickness is an issue you would always go with an aspheric over a spheric. Any power can benefit from an aspheric front base curve design. I don't know of any advantages to a spheric lens unless using SV to create wanted prism.

[@Quilter1977]

I normally use single vision, but I'm getting bifocals for sewing with, and trying to decide between CR-39 and 1.6. I'm -8 -1.5 170 and -6.25 - 1.5 30, I normally get 1.67, but I want the best possible optics for this, as long as they don't get truly ridiculous. The frame is 49-15-46-130, acetate, and I don't know my PD but I'm guessing 61. I'm mostly petite but my head width isn't, so it's a nightmare finding frames.

[@LaramyKOptical]

Nothing wrong with 1.67 or the 1.60. CR-39 would be terrible with those powers.

[@Quilter1977]

@@LaramyKOptical I have an old pair of glasses in CR-39, as a matter of fact! I have a circadian rhythm disorder which makes me supersensitive to blue light, I need to block it entirely for three hours before bed to stay on a 24 hour day. This means a bright orange tint, it's nothing like those silly "blue blocking filters" which we all know are rubbish, and they couldn't get it right in high index on previous occasions. They're in metal frames, 49-16-135, but they're nine years old when frames were shallow, so the B measurement is only about 26. Anyway, the visual acuity is fine, as far as I can tell with that tint on. But I don't try to do sewing with them on, I wind down for bed, so it's just reading and watching TV. They get to about 6-7mm thick on the outer left side, and don't stick out of the frame much mostly. These will have a B of 36, which I realise will increase the thickness at top and bottom. Anyway, thank you, good to know. I think I'll go for the 1.6. I'm mainly just worried about losing more visual ability. I haven't been able to read a paper book in years (I have severe ME/CFS, my muscles don't work well) and already have four spotlights on my sewing desk.

[@ivoshterev]

Mr. Seegers, thank you for your videos. What are you thoughts on "anti-fatigue" lenses? I was recommended such Shamir "Relax" lenses by my eye doctor. I am 36 years old, near-sided (-2.5), but also have an ADD of +1.00, and still using single vision lenses, spending most of my day on the computer doing accounting work. One one hand, I am happy that progressives are not yet necessary for me, but are "anti-fatigue" lenses worth it or just another marketing "gimmick"? Thank you.

[@LaramyKOptical]

My opinion and my opinion only. You always hold out as long as you can with nothing. As long as you can do your work then leave the add power and anti-fatigue stuff alone. It's like religion and politics. Some people believe in anti-fatigue while others believe that providing additional plus or reduced minus early is harmful and causes premature dependence. IMO skip it until you need it. John

[@ivoshterev]

@@LaramyKOptical Thank you for the advice!

[@redgreenbeambih]

Absolutely not go with the Anti Fatigue for sure especially now with CVS Computer Vision Syndrome a +1.00 is kinda high for a 36 yr old already too like your not even 50 yrs old yet! Always listen to your Dr and not an Optician lol!

[@Nekoandpiano]

Add is a serious thing. And really should be decided with Dr. After mesuaring your existing accomodation recourses.

[@LaramyKOptical]

@@Nekoandpiano No, an add is NOT a serious thing at all. Vision is subjective. You don't need a "doctor" to slide a reading card along a meter long stick.

[@Chicken1111]

First off, I want to thank you for your channel. I feel much more confident as an optician thanks to you. I have amazing mentors at my job, but you answer more of the “WHY do we do it this way” questions I have. I had a patient previously do a CR39 lens with a (~+2.00) rx wanting to thin out her lens and make it lighter. I ended up putting her in a 1.67, which was the lowest high index her insurance’s lab would do. I told her doing a 1.74 would be wasting her money. I later asked one of the doctors, not my mentors, if it truly would’ve made that much of a difference in a 1.74. He said “well, if she’s willing to pay for the 1.74, why didn’t you let her?!” Which felt a little predatory. Thank you, thank you, THANK YOU!

[@LaramyKOptical]

You are welcome. 1.74 would have been a terrible choice for any number of reasons. You 100% did the right thing. If thickness hadn't been mentioned with that power 1.60 or even Trivex would have been fine choices also.

[@Chicken1111]

@@LaramyKOpticalI currently work at a semi independent shop, her specific insurance used an outside lab. I was hoping for a 1.60, but her insurance plan and/or the lab doesn’t provide that option. I didn’t check for Trivex- that would’ve been a great option… I’ll keep that in mind!

[@jenniferpesina8927]

my pet peeve is solutions or options only being presented for myopia and not hyperopia for +4 diopter and higher

[@LaramyKOptical]

Feel free to drop me an email through the OpticianWorks website. Maybe we can help? Several of the videos go into great detail on how you get the thinnest possible in +.

[@pow-hypeentertainment9131]

Where can I get certified online as a optical technician

[@briapaige]

I was under the impression Trivex was thinner than poly… what is the benefit to Trivex and when should it be used?

[@LaramyKOptical]

Several other videos cover that and you have the OpticianWorks.com program too.

[@briapaige]

@@LaramyKOptical thank you so much! Just got it yesterday! I’m looking forward to learning more

[@opchick0597]

Thank you for another great video.

[@danielpandele4278]

Hi!I wear prism with toric lenses in both eyes, OS -0.50 cyl axis 90 2DP BU, OD -1.25 cyl axis 115 2DP BD, my PD in small 58 mm(adult 34 years medium to big head), and i noticed that my vision is very dependent on the position of the glasses(the OC height is a problem).My question is, will free form lenses improve this inconvinient?And should i stick to standard CR39 or try 1.6?thank, hope that you don't find my questions stupid:)

[@LaramyKOptical]

I'm going to kick this one over to Janet at the lab. Give it a few and we'll get back to you. My quick thoughts are: An accurate OC height isn't hard to get and I'd go with Trivex or 1.6 over CR-39 any day. Let's see what Janet says...

[@pandeledaniel3855]

Thank you!Can't wait to hear your opinion(or Janet) if should i get freeform or not🙂🙃😉

[@janetbenjamin7090]

@@pandeledaniel3855, before I chime in here, is there a sphere power in your RX, or is it R) Pl (or 00) -.50 axis 90 L) Pl -1.25 axis 115 with your prescribed prism?

[@pandeledaniel3855]

@@janetbenjamin7090 Hi,no sphere, just cylinder left eye -0.50 axis 90 degree and 2 diopter of prism base up, right eye just cylinder -1.25 axis 115 and 2 diopter of prism base down!If you provide me your email i can send you the prescription from the eye doctor🙂

[@ngNudraconis]

Thank you so much.

[@Jusdutari]

Hello, I wasn’t informed properly when I made a purchase of lenses and I bought a pair with a High Index of 1.74, my prescription is -5.25/-4.75. Will that have vision disadvantages (less quality) against going with a lower index? Thank you

[@LaramyKOptical]

That is serious overkill for those lens powers. Depending on the quality of the lens and non-glare coating you may find the 1.74 more prone to aberration than the lower index. Vision is subjective and a matter of perception so no way to say "yes" or "no." Only "yes" poor choice of material for power. John

[@Jusdutari]

@@LaramyKOptical Thanks John. As you said, sometimes (rarely) I do notice the aberrations and I will discussed with my Optician, they do have “in my perception” a good AR coating by “HB Optical Labs” called “DURAR Ultra UV”. Now in your opinion, I want my lenses to be thinner than CR39(my previous had it), what index would you recommended me they have 1.60/1.67/1.7? Thank you again.

[@LaramyKOptical]

Watch the other videos about the importance of frame choice and then either a 1.60 or 1.67. With a smaller frame and just a 5.25 I'd lean towards 1.60. You'll save some money for sure!

[@ikarugaxx3749]

They took more money that it was legitimate from you, that's what they did.

[@Fireneedsair]

Hi there. Would it be possible to make a -6 glass lense hi index, ie: as thin as 1.67? Thank you

[@LaramyKOptical]

There are hi-index glass lenses in a 1.8 I believe. But that would be serious overkill for a -6 and a 1.8 is going to have some optical issues. I doubt you would find much thickness difference between a well made 1.67 or 1.74 and a hi-index glass in that power. But if you have to have glass for some reason it can be done.

[@Fireneedsair]

@@LaramyKOptical isn’t a 1.67 glass lense considered a “hi index” lense? Thank you

[@Fireneedsair]

@@LaramyKOptical a few more questions. Can a glass lens be made into a round shape to fit a frame? And can a glass lens be made bifocal/progressive? Thank you

[@LaramyKOptical]

@@Fireneedsair To be perfectly honest I don't even know what index glass lenses are available in. They are so rare. BUT! A glass lens can be made in any shape. Glass lenses are available in most lens styles including progressives. We may be able to connect with you someone depending on where you live. Better to email me through the OpticianWorks website. John

[@Fireneedsair]

@@LaramyKOptical thank you! I'll email you asap

[@melissayouell8629]

Thank u john

[@nemesis851_]

Thanks John!

[@Denisio185]

Thanks!

[@markperez9912]

I want to learn more how to be an optician sir laramy i hope you will teach me more

[@MrBsantini]

This video is like a WWW wayback machine: It’s a peak into the exact thinking of a 1990’s optician

[@NINJA_INVESTORS]

He takes too long to get to the point. Good info though

[@LaramyKOptical]

I'll let him know. John

[@shrek22]

It's 2022, and he's against online sales. What a lunatic.

[@LaramyKOptical]

Where on Earth did you get the idea I'm against online sales? I take offense with that since I am one of a handful of opticians that does NOT bad mouth online sales at all. I do recommend that people see an optician when they have high powers or need a progressive. I also have no issues with helping brick and mortar stores fight against online - that is something very different. We don't do that by assumptions or bad-mouthing we do it by offering something better. Online eyeglass sales have been around almost 25 years now - you'd have to be a bit daft to not recognize it. Heck, low powers - single vision I've encouraged people to shop online.

[@cni2i]

@@LaramyKOptical Good for you John! Online sale of eyewear is a definite "hit or miss" situation. Great if it's a hit, but a BIG headache if it's a miss. There's a lot more than the sale of a pair of eyeglasses...it's the connection and trust that is developed between the patient and the optician. Sure there are those people out there that value convenience and price over precision and individualized eye care, and that's what online sales are for. But there's a reason why patients still come see their opticians in person.

[@HRTsAFyre]

I never heard say that. But he's right progressive lenses should be measured in person. My issue is my insurance plan doesn't have glasses to choose from after my prescription is written. I bought my last pairs online and had no issues. They went out if business. My new vision plan has their own online store. I'm not happy with my new progressive glasses and knowing I wad getting progressive lenses with astigmatism the optometrist didn't even get my PD on the script. I had to go back, then what about the height of the pupil? Ugggh I would gladly have this gentleman fill my script. I challenge him to use my old rimless frames with the nut and bolt mount . That company even sent me a screwdriver to tighten them in case they got loose. One bolt finally got a tiny bit loose after 6+ years