How To Use The Lensmeter - Vertical Imbalance Or Prism?

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How To Use The Lensmeter - Vertical Imbalance Or Prism?

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7 жыл бұрын

Learn how to recognize vertical imbalance using the lensmeter. This lesson includes reading the lens sphere power, cylinder power, axis. The video lesson will demonstrate how to recognize and read the prism of vertical imbalance vs. prism between two mounted single vision lenses. Learn More: opticianworks....
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This week, we learn how to recognize vertical imbalance using the lensmeter. This lesson includes reading the lens sphere power, cylinder power, axis. The video lesson will demonstrate how to recognize and read the prism of vertical imbalance between two mounted single vision lenses. When one optical center of a mounted eyeglass lens is placed higher or lower than the other it will create vertical imbalance and prism. Verification of lenses is part of the job of any optician. Opticians use the lensometer to verify prism in eyeglass lenses. Opticians use the lensmeter to read prism in eyeglass lenses. The verification process is also known as lens final inspection or glasses final inspection. The Learn the Lensmeter kits are available for OpticianWorks Total Access members to check out. Instructions for requesting yours are in the OpticianWorks lesson on using the lensmeter (focimeter, vertometer). Each kit contains various types of lenses, frame fronts and assignments, to give you the ability to gain some practical experience. Learn More: opticianworks....

This video lesson is sponsored by Laramy-K Optical
Laramy-K Optical is a digital uncut and coating lab unlike any other. The only exclusively uncut lab in the country; we provide our customers with independent, high-end alternatives to corporate brands. Through craftsmanship, technology, and independent, innovative vendors like Younger, IOT, A&R, and Quantum Innovations we offer our customers the Integrity portfolio of freeform lenses and coatings. Made in the USA, the Integrity brand is not a generic house-brand, but is the absolute best available, designed to give the wearer that “wow!” experience.
In addition to the digital line, we still offer conventional surfacing, including glass. Maintaining traditional equipment gives our customers vastly more flexibility in their dispensing, particularly when it comes to more difficult prescriptions.
Learn More: www.laramyk.com

Пікірлер: 44

@Dustin_Platt Ай бұрын

What if the patient doesn't have an "average" OC. How would you go about a strabismus like hypertropia on a lensmeter for example?

@drwillfranklin1 3 жыл бұрын

Thank you for the refresher sir.

@iokuok2 6 жыл бұрын

"Send it back to the lab! " Thank you Thank you, John Seegers for profoundly stating the all too simple case for quality control!

@LaramyKOptical 6 жыл бұрын

;-)

@toddpa-c3826 6 жыл бұрын

Great Videos John !! However not to sure how I feel about the cut and dry statement of sending it back to the lab, especially if they are actually correct and legal. I totally understand the angle you are coming from with this visually, however Over the past decade, it has saddens me to witness 1st hand the amount of “Professional s “ out there that Choose NOT to work at the “TOP of their licenses” Sure its different for each person on their journey, however it amazes me at the sheer number of opticians that obtain licensure and then choose to not keep up on the newest technology or how to apply it in their practices effectively to benefit their patients as well as make them happy by getting their glasses or contacts to them as soon as possible, while building a profitable practice that actually utilizes (and just as important Understands) all if the newest technology that our labs such as yours offers. Its amazing where we have come just since the late 90s with equipment. I know your busy with all your projects regarding helping newbies pass their ABO- but if you ever would consider brining us into understand your equipment and how it can benefit both our patients as well our practices...

@darkcalling9211 2 ай бұрын

so vertical imbalance is present when the proposed fitting heights/OC height and PDs are binocular. But if a single vision lens was done monocular and one eye is higher/ lower than the other and you see what is present in the video, you'd dot OC and measure OC height and verify that it matches height ordered, yea?

@LaramyKOptical 2 ай бұрын

Please see the 3 part series on Verification & Final Inspection. Thanks

@geselles 5 жыл бұрын

Can you go over how to use the prism compensation knob. Thank you for your videos. They are great!

@LaramyKOptical 5 жыл бұрын

It's in the works now. Hopefully by the end of the year. John

@Lmtdtw731 6 жыл бұрын

Hi John, Love your website and your videos, thank you! I am puzzled though about why you are wearing green gloves while using the lensometer. I know it’s irrelevant to this video lesson but “curious minds”. lol

@LaramyKOptical 6 жыл бұрын

That is my helper that I work with on these difficult shoots that require multiple camera angles. John

@bidhunaraj5308 5 жыл бұрын

Helpfull video...👍 Please show how to find near vision power in sphero cylinder lens using lensometer ..............

@LaramyKOptical 5 жыл бұрын

Reading a bifocal has it's own video. Near powers in progressives you read off the laser etchings not in the lensmeter. John

@anthonyz1556 5 жыл бұрын

Hi John, Your videos are so helpful as references when a problem comes up. Quick question though. If I take dot up the pupil on each side of the demo and the patient's OC height differs dramatically, would you recommend submitting the order as is (for example OC height is OD 24, OS 27) or is it better to split the difference? (OU 25.5)? Much appreciated!

@LaramyKOptical 5 жыл бұрын

Hmmmm. great question. Assuming we are talking about OC heights not progressive fitting heights. Assuming we have enough power that it matters. Assuming you can just look at the person and easily see the difference. I would take it as I see it and go with 24/27. Try to keep OC shift in the vertical around 0 - 5mm. John

@Leilaskips Жыл бұрын

Which eye do I have to start? The strongest power!

@LaramyKOptical Жыл бұрын

You'll find an entire series here: kzfaq.info/love/dfKXBLjBDbX2X2g0XuAbmwvideos

@LaramyKOptical Жыл бұрын

Or far better OpticianWorks.com

@javierlope733 2 жыл бұрын

Hello I just started a new job I have been struggling checking the rx on progressive lenses and sv. We use digital lenses most the time and I have been unable to properly check the rx correctly. I hat I am doing wrong? I am not to sure the exact location of the PCD, how do i setup that piece on the lensmeter

@LaramyKOptical 2 жыл бұрын

Several other videos on lensmeter use and you have 3 on verification/final inspection. Email me through the website - I think I have a progressive specific sheet. It isn't anything special but it might help. And if your lenses are digital or free-form then you can't really check them using a lensmeter. You can get close, sort of, but to really tell you need a dual lens mapper which is what they are using at the lab. Within reason you have to trust the lab and your gut. John

@allyn9269 5 жыл бұрын

Hi John, I have a question. We we're told by our Prof's that in order to find the Vertical prism in the Lensmeter, we have to start reading the lens with the strongest power in the 90° meridian. What does *strongest power" mean in this case? Is it the power with the highest number? Or the power with the higest plus? Like for Ex: Given the Rx OD -2.25-1.37×079 OS +4.00-2.00×076 Which lens is the strongest base on this Rx? Thanks

@LaramyKOptical 5 жыл бұрын

Ling Ling, You need to do either the % rule or the power in oblique meridian formula to determine the power at 90. I cover both in detail in the early videos. You can't tell by looking. In this case you could probably get away with the % rule using 10 degrees away and 15 degrees from what you need. How to determine the power in the meridian should come before attempting prism questions. So go back and start the video series from the beginning. John

@toddpa-c3826 5 жыл бұрын

Os correct ?

@eddiekent1997 3 жыл бұрын

Marking a plus or minus lens right or left for prism using the lensmeter.

@LaramyKOptical 3 жыл бұрын

kzfaq.info/get/bejne/oq6Tg7CSrsWnqGg.html

@veggiesub7224 2 жыл бұрын

great video

@skieye1 7 жыл бұрын

Nice job John. You da man!

@LaramyKOptical 7 жыл бұрын

Thanks again!

@endersgame7277 5 жыл бұрын

Am i right in this statement, no matter if the lens is + or - , when i look in the lensometer if the prism is base down when im reading at the OC then the sphere and astigmatism line will cross below the center of the reticule? Similarly base up would be above the reticue?

@LaramyKOptical 5 жыл бұрын

Pierre, Sorry I have been thinking about this all day and can't really think of a way of answering it. If you are reading something at the OC then you will not have any shift in the target position. I'd grab a +2.00 and a -2.00 sphere and play around with them until you get the answer you are looking for. I'd have done that but I'm not sure exactly what the question is. John

@MsTracyBennett 5 жыл бұрын

"I hope it obvious, but vertical imbalance is only present in mounted pairs." LOL!!! Exactly!

@anonymoussoul3256 Жыл бұрын

Sir if we rotate our lens at every angle power will be same to our eyes.... Lens power is spherical-3. 00 cyl-1. 00 nd axis 10

@LaramyKOptical Жыл бұрын

Not if it has cylinder only if it a sphere alone. 5 other videos on how to use the lensmeter and OpticianWorks.com.

@anonymoussoul3256 Жыл бұрын

@@LaramyKOptical sir actually on rotating lens 90. I see the image is blurr.. Is it ok????

@LaramyKOptical Жыл бұрын

@@anonymoussoul3256 You are watching the wrong video! Search KZfaq for Laramy-K Optical and then find the other 5 videos on the lensmeter. You are missing ALL the foundation work. You are watching the last in the series first. You are somewhere between 5 hours and a few weeks away from really understanding how to use the lensmeter. Slow down, reset your starting point and begin again.

@Tanjaamazon Жыл бұрын

Can't with my bad knees

@carolynhollinger1352 4 жыл бұрын

Hi John, question for you on reading prism. The answer may be similar to what you told Allyn but I will ask anyway at the risk of sounding like a ding dong. I am currently reading lenses with a BO of 3.50 in a progressive and it is showing WAY out there on the rings. It's -4.00 sphere with -1.00 cyl and an add power of 2.00. Is this common for a progressive with prism to read outside the field of vision in the lensometer?

@LaramyKOptical 4 жыл бұрын

NO! For reading prism on a progressive it is straightforward. WYSIWYG. Place the lens in the lensmeter at the PRP with PCD at 0/90 or neutral and read what you got. If the job calls for 3.5 BO that is what you should have nothing beyond that. John

@rake48llll85 5 жыл бұрын

could you do a video using a prism compensator?

@LaramyKOptical 5 жыл бұрын

I cover the PCD in the video on the lensmeter and progressives. I have never used it (or prism rings) for anything other than bringing the target into place when working with progressives. Using the PCD or rings for neutralizing high prism is outside my area of expertise. When I get out to the lab again some day I'll try to have John show me how it is done so I can try to do a lesson on it. In the meantime you might want to look for a wholesale optical lab in your area. You might luck out and find an old-timer willing to show you. John

@toddpa-c3826 5 жыл бұрын

I know you would never move the table in the past to check for vertical imbalance since it defeats the purpose to calculate it - HOWEVER unlike the last - when fitting hts where the same - how or does this play into effect for checking PALs with 3mm differences in HTS in PALs ? Many times I see these digital measurements and I question myself....... Finally same goes now for SV - but utilizing Mono OC HTs could you help me understand that you could actually move the table and then measure (if i am correct in saying that ) because if fact by ordering mono OC Hts in SV your actually inducing prism from the doctors original RX..... during my time with refraction - our phorotopter always was straight on the pt in the exam room so why when people are esp using digital hts - 1- are they not already inducing prism And changing the Mds rx by placing them sometimes 3 or 4 mmm apart ? I have had pts have issues with this , and remade them equal or matched the location of the old pair equally - however when i am checking them now - i dot and measure the OC ht vs what is ordered because if not i see the prism we induced from following the order . So i check measuring the hts individually and move my table to center each way. As i told my opticians - I never saw a phoropter in the exam chair refract by making one eye higher and one lower like they are trying to do in the finished glasses - if the pt needed that - he would just slip in a prism wedge when th was refracting and never had us actually induce prism by placement. Hope that makes sense !! Appreciate all u do !

@LaramyKOptical 5 жыл бұрын

I think the short answer is - if the job was ordered with two different oc heights then you would figure that the targets would center in two different places, dot them up and the center dot should match the oc height requested. If they do all is good to go. Kind of seems like you might be overthinking this one a little? John

@matthewbalas5610 4 жыл бұрын

I have come across a few times when I pull a stock lens. Let's say a plano -1.00 x 180 and the oc will not be perfectly centered in the reticle. Sometimes it will show like 1/4 prism in any direction depending on the axis I need it at. So if I have a plano -1.00 x 180 lens, it should just read plano at the 180. But because the lensmeter reads 1/4 or 1/3 prism, do you think it is really actually there or that the lens manufacturer just passed it because it's not enough prism to make a difference?

@LaramyKOptical 4 жыл бұрын

Did you catch Tracy's comment below: "I hope it obvious, but vertical imbalance is only present in mounted pairs." LOL!!! Exactly! You can't have vertical imbalance in a loose SV. It is your job to move that lens to the OC. Do low power and no power lenses have OCs that appear "off" yes! There simply isn't enough power there to focus the light. You can move a 0.00 -1.00 around until the cows come home and it won't make much difference. That is basically my lens power and I just get a good solid lock on my axis and shoot for the middle. John