Measuring a mm with a caliper is just not accurate...measure 20cm where you should see a change because beeing wrong can amplify with size.

@LaramyKOptical

2 жыл бұрын

Error may amplify with size I'll give you that. Certainly not a bad idea to try 20mm. But - assuming my calipers are accurate then measuring a mm with them is accurate. Your way of thinking would mean that the calipers accuracy increases with the size of the object being measured. A mm is still a mm. But - again - measuring 10, 15, 20 would not be a bad idea at all! Thanks

@omidel.

2 жыл бұрын

@@LaramyKOptical i often find rullers with 1-2 mm error at the top end ...I love your videos sir(I learned a lot from them). Thank you

@olicook4153

2 жыл бұрын

I think his way of thinking is exactly the same as any engineers. If your measuring something the vernier jaws can fit around and can be used how they are intended then they are as accurate as the calibration label suggests. But if your offering them up to a ruler to check 1mm is accurate, it is only as accurate as your eyesight. If your rule was .025mm out, would you really notice by offering up the verniers like that? If you measure 20mm, that .025 per mm is now a full .5mm. That’s easily distinguishable. The margin of human error for aligning the jaws etc is now taken out of the equation. I don’t think he was suggesting that a calibrated measuring device doesn’t measure smaller measurements as accurately as larger ones. It’s us humans who can’t. Infact, cheap digital verniers tend to have bigger issues when going into larger measurements as they can loose track of there own scale if you open them too quickly etc. so as it was clearly suggested, the way your using them would be a lot more accurate for it’s intended purpose if done at 10/20mm. But I guess, if your allowed a give or take of 1mm in the prescription without having issues then unless the glasses are of normal size, as long as the ruler looks ok, it’ll do 👍

@LaramyKOptical

2 жыл бұрын

@@olicook4153 Agree 100%! I wish I had thought of that and suggested a 10mm and a 20mm test. The way the opening statement was worded threw me off - but I did agree with it. Of course unless a shop is old enough to have had a pattern edger they probably don't have calipers around anyway. Thanks for the follow up. And I'll pin this thread at the top of this. John

I was a metal fabricator for years. I am finding this so interesting. I love it when you brought out the calipers

Hello Laramy, here I'm again...thank you...

Hint, opticians work almost exclusively in the metric system

I am trying to study optometry. I did not expect a comedy break in the beginning. I died laughing, I paid no attention to the rest of the video. I had to watch the video over to understand what was being said. I am not in school optometry, however I am learning for my own benefit to understand.

Start by purchasing a high quality rule. (We don’t call them rulers). Starrett and Mitutoyo are excellent brands.

@LaramyKOptical

7 ай бұрын

Good advice!

After getting 4 different results from 4 different people (I was one of the 4) in measuring my PD at home, I decided to try a different method. The measurements varied from 64 to 69, and I considered this unacceptable. Here's what I came up with. I took an 8 1/2 by 11 piece of card stock and went around the edge marking 64 thru 69 mm distances. I then punched small holes with a leather punch at these various distances. Next step was to look at an object across the room and see which set of holes gave me unrestricted vision. Not perfect of course, but I felt more confident doing it this way over the PD ruler. It also revealed that it made a difference where you were looking, up close vs far away. I certainly see the advantage of using the pupilometer, but I wanted to go online for a change and needed my PD. Love your channel. Wish I'd discovered it sooner. Curious what your opinion is of my 'method'.

@LaramyKOptical

Жыл бұрын

Sorry - But the one thing that a PD stick is never used for is taking a PD. The last optician to do that died twenty years ago. For measuring PDs we have the pupilometer and now the electronic measuring devices like OptiKam Pad. Both very accurate and compensate for gaze and convergence. Unless you have very strong lens powers (or wearing a progressive) a mm one way or the other isn't going to matter much. If you feel comfortable with your method - GO FOR IT! Sounds a bit complicated to me - but I'm wrong about so many things. (Can't help but notice you have a binocular measurement there.)

@LaramyKOptical

Жыл бұрын

kzread.info/dash/bejne/pa5lybCJcrDRiKg.html

@donaldschlag8277

Жыл бұрын

@@LaramyKOptical Even more impressed with your website after such a quick reply. I had already watched that video a couple of times and considered getting a pupilometer. The problem was that that would cancel out most of the cost savings of going online. Also, I would still be depending on someone else doing the measurement. I meant to mention that I realized it was a binocular measurement. I wouldn't be surprised to end up getting a pupilometer anyway.

@LaramyKOptical

Жыл бұрын

@@donaldschlag8277 Since you have watched a bunch of videos you have already heard this but I'll repeat myself. If you have high powers and/or progressives you can't shop online. If you have low powers in single-vision you can shop online and then a difference of a few millimeters one way or the other isn't going to make any difference at all. See the three part video series on Verification - Final Inspection.

@danielch6662

Жыл бұрын

@@donaldschlag8277 it's likely parallax errors that you're seeing. If your assistant is up to it, just explain the problem. I was a school drop out who never went to university, but fortunately for me my sister is a phd. She understood immediately. 😁 Otherwise, you need to take charge of the measurement yourself. First off, you need to place something between your eyes for the ruler to rest on while the measurement is being made. This ensures the ruler doesn't slip and move around. I use a piece of plasticine. An optician wouldn't do this to a customer, but hey it's my own face. If you don't have that handy, take a hankerchief, soak it in tap water, and squeeze it dry. You want it slightly damp but not dripping wet. Your assistant must be directly in front of one of your eyes when lining up the 0. Make sure they close one of their own eyes. Use their free hand if they have to. Then you help hold the ruler as they move to your other eye and read the measurement with THEIR SAME EYE. Ensure that they are properly lined up. You could do this yourself with a mirror, using the appropriate eye one after the other. But I'm -6.75 and -6.50, and I can't read the ruler without my glasses. And needless to say, the measurement should be made with your glasses off. But contacts should be fine.

How about when checking a pd on a finished wrap sunglass? Is it correct to keep the ruler flat across the bridge and not bend the ruler to the front curve on the sunglass while checking a pd measurement?

@LaramyKOptical

2 жыл бұрын

mm rules are never used to get a PD. If you were forced to try for some reason you wouldn't have the customer wearing a frame of any kind.

@danielch6662

Жыл бұрын

@@LaramyKOptical I think Alexis might perhaps be measuring the PD of the frame instead of the person wearing it, in which case it should obviously be DBL + A as you stated in the boxing video. Though, why would anyone want that. Maybe those are prescription sunglasses?

@LaramyKOptical

Жыл бұрын

@@danielch6662 Great catch - yeah with the benefit of hindsight maybe that is what she meant. (DOH). If the subject is of interest to you watch the video High Curve Step Bevel in the edger. PD/Frame PD comes up there.

Can u please answer my question? My husband is interested in getting licensed. Is he able to buy books, self study and go and just register for the ABO & NCLE test without working at an optical?

@LaramyKOptical

2 жыл бұрын

opticianworks.com/about-opticians/

ᑭяỖｍｏ?? ?

But you have missed out the most important part, all your measuments will be wrong as you have not told the px to look in each of your eyes when measuring

@LaramyKOptical

2 жыл бұрын

No, didn't miss anything since the one thing we never ever use a PD stick for is taking PDs. That is what the pupilometer or electronic measuring device is for. We just covered that in the video two weeks ago.

Your pd will be too narrrow