Basic Lens Styles: Single Vision, Flat Top, Bifocal, Trifocal, Round Seg, and Executive

[@jailoeil]

I am a french optician. I equiped a lot of children with round bifocal lenses. The most of the cases were because the children have disorders with their convergence. Often affected by convergence strabism (I'm sorry for my english translation if that is not correct). The goal is to avoid accommodation for the near vision. Even if we can place any bifocal lens, the round one has two advantages : It is the more discret, and because it is made undisctintly for a right or left lens (the lens manufacture use the same semi-finished lense and rotate for the axis , 10° anticlockwise for a right lens, and 10° clockwise for a left lens) we can use this kind of bifocal closer to the nose and upper (after an axis recalculation). The 38 mm round bifocal is probably the preferential for this use. Another point with round bifocal : it exists with very high additions for low sighted persons. They could see closer, then bigger, but monocularly. By the way, I really agree with you, the trifocal executive is absolutely the worst thing to wear. 😂 I hope that I answered to your interrogation. Best regards.

[@LaramyKOptical]

Wow! Thanks! 10+ years now and someone has finally answered the question. It took a small miracle and someone from another country to do it. I'll pin this comment to the top for others.

[@jailoeil]

@@LaramyKOptical I'm glad if I helped you to learn something. I'm in use to be at the other side. 😉

[@MẮTKÍNHTlTAN]

Thank you so share with us. Great video!

[@CheesepoofKat]

I was fitting a patient with a executive bifocal and it came back as a trifocal, and I had to tell them that I didn’t even know it existed, hahaha. My senior optician was like: we need to keep these.

[@Freefall347]

Not sure if you've received an answer on this, as the video is over a year old now, but where I work it is relatively common to fit children into a FT28 if they are having problems with overconverging at near. Basically the idea is the added power of the segment prevents the child from using their natural accommodation, which also prevents them from going cross-eyed and hopefully allow their eyes to develop enough strength to remain ortho. I would assume that a RD seg is used for a similar purpose, but perhaps is considered to be cosmetically superior. If that wasn't the question, then I'm not sure what the purpose could be either.

[@LaramyKOptical]

Thanks. It was more a question about why a round segment. It really is one of those persistent optical myth things. Mention segment and kid and someone will say round - but - nobody knows why or has actually used one in that application. John

[@nicoletataru]

Laramy-K thank you so much for all the videos, I did learn so many new things from you ! The guy from the video what is explaining it's brilliant, love you ! Thank you again, you guys are brilliant. Greetings from 🇬🇧

[@LaramyKOptical]

This is guy in video. THANKS! John

[@TariqFaheem-wz8xd]

Most Informative❤

[@leaniepienaar2889]

Thanks so much! Great fun watching this! 🤓

[@LaramyKOptical]

Thanks for watching!

[@enriquesanders]

Amazing video! What about no line bifocals? I have those and work great but I cannot find a lot of information about them online.

[@LaramyKOptical]

Sure several of them: kzbin.info/door/dfKXBLjBDbX2X2g0XuAbmwvideos

[@ВолодимирОлександрович-п2л]

Great lesson! Thanks!)

[@ackman3981]

Why do I hear "milliliter" instead of "millimeter" at about the 9:55 mark?

[@DonGabby007]

What should be the differences between a lined fused or rounded bifocal and an invisible blended bifocal. Assuming both Rx are Plano ADD+1.00

[@LaramyKOptical]

Not sure exactly what you are asking. Fused would be a glass lens. A blended was/is a round with the edge of the segment smoothed out - which creates a blur area.

[@DonGabby007]

@@LaramyKOptical I mean to ask, what would be the obvious difference between fused b/f and blended Invisible bifocal. I also compared plano ADD+3.50 in both lens types and could not find a difference.

[@LaramyKOptical]

@@DonGabby007 Anything fused should have no ledge or edge or transition area between the different sections of the lens. A blended bifocal will be a round seg with a noticeable blend/blur line. If you hold it up to light you should be able to see the pattern around the segment. Both are very old, very dated designs. Very, very rare to find in this part of the world.

[@nileshjoshi99]

R u there in India? Mumbai?

[@mohammedameen5937]

I am a big fan of u sir

[@LaramyKOptical]

Thanks!

[@SrinivasanK77]

My prescription: Right eye Sphere: +0.75 Cylinder: 0.00 Axis: 000 NV: +2.00 Left eye Sphere: +1.50 Cylinder: -0.75 Axis: 065 NV: +2.75 What would be my reading glass numbers? I wanted to have a progressive lens (at outside) and reading glass (at home). Please help.

[@LaramyKOptical]

kzbin.info/www/bejne/fXeagoGoid1_ebM

[@luisgomez1211]

Mr. Laramy, I'm here again learning from you...thank you...

[@LaramyKOptical]

Always glad to have you stop by.

[@goodwill6767]

I am still researching lense options in preparation for my eye appointment in less than a week so I have some idea what questions to ask. I'll be so glad when all is settled and done. You say that for those who opt against progressives can choose flat top bifocals with a separate pair for intermediate tasks. Opticians seem to have varying opinions about the future of lined trifocals with some saying that will soon be non-existent and others saying there will always be a small market for them. Who knows what to believe until it happens? If the progressives don't work for me and I opt for lines I thought maybe I should get used to not being able to get trifocals anymore due to increasing unavailability and get lined bifocals and a separate pair for intermediate. But there are just so many things I do at work that need all three distances. My question is whether you find that people who abandon lined trifocals and return to bifocals find they miss the intermediate zone they had before they changed. Thanks.

[@FranktheDachshund]

I asked my eye doc if I could get the bifocal on the upper part of the lens, the moron told me no.... So let me ask you a new question, can I get the main body as intermediate, top far, bottom close?

[@LaramyKOptical]

Only if you can find someone willing to do something 100% custom like this: kzbin.info/www/bejne/nHuUhJtrftdqo5I Otherwise it has to be distance - intermediate - near or near - intermediate - distance. You can't place them in another order. Or at least I can't think of a way to to do it unless custom.

[@fredparsons5134]

I tried to have top reader bifocal made too and didn’t have any luck. It would be great for people who are working above their head level so the y don’t have to bend their neck back to see through a bottom bifocal. Like working underneath a car on a lift.

[@goodwill6767]

I got lined trifocals last year because I started having difficulty with intermediate vision. I have actually found them very useful and helpful. But according to this they are getting rare. I'm now concerned they may become unavailable. How will I accommodate intermediate vision without being forced into progressives?

[@LaramyKOptical]

Should they reach the extinct point (not likely in the next 30 years) then you would use single vision intermediates.

[@goodwill6767]

@@LaramyKOptical Thank you for your reply. But single vision intermediates don't seem like they would help in the case of someone performing tasks requiring near, intermediate, and distance vision in quick succession.

[@LaramyKOptical]

@@goodwill6767 You might be quite surprised at how flexible a bifocal can be when you play with the add power a little. In our world today it isn't all that often we need distance, intermediate and FULL near every day all day. If you find the right optician they should be able to come up with something that meets your needs. Or at least give it a heck of a good try... But I also doubt the world will run out of tri-focals any time soon.

[@goodwill6767]

@@LaramyKOptical Thank You. That does provide some consolation, especially about playing with the add power in the bifocal. In my public school music teaching job I must be able to read papers at close distance, musical scores at intermediate, and watch how students are using their fingers/voices at far distance. For my church organist job I change to occupational intermediates and it works fine for that, though it is a little difficult to watch what the ushers are doing in the back of the church so can get cues I need. I would jump on the progressive lens band wagon if they offered wider reading distance and no side distortion. This is why I have avoided them in favor of lines. It also seems like progressives would not accommodate reading something much deeper than a line of text if the keep progressing downwards. Hopefully the industry will either sympathize with those of us with these issues or make improvements that accommodate them. In any case I will continue to exam and study your excellent and informative videos. You provide so much information that I suspect the general public never thinks about. Many thanks for your responses.

[@feelinglikevinyl781]

Thank you for this video. You opened my eyes to the good old bifocal lens that I'm so happy with. I struggled for years with progressives and their "land of optical garbage". Thank you for encouraging me to give bifocals a try!

[@azca.]

Saint-like

[@LaramyKOptical]

I have been called many things but saint doesn't come up very often. ;-)