Is it necessary to take an EQ when making one lens IF there is prescribed horizontial (in/out) prism? There are 4 opticians that all have different answers here so I would appreciate your answers. Thank you!
Is it necessary to take an EQ when making one lens IF there is prescribed horizontial (in/out) prism? There are 4 opticians that all have different answers here so I would appreciate your answers. Thank you!
Pardon my brainfart, but what, exactly are you asking?
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
When we re-order one progressive lens rather than a pair we take an EQ. We read at the PRP (prism reference point) from the existing lens (generally it is base down prism) and we notate the measure ment to le lab so we aren't creating a prism imbalance in the lenses. However my question is do we need to take that measurement if the doctor has prescribed prism in the pts rx.
Yes you do.
not be rude but can you explain why, if you don't mind. Reason being is one of our opticians argues that if the doctor has prescribed prism then that is what you will always read at the prp and nothing else (so if dr says 1 out it will only read 1 out at the prp never 1 out 1 dn)
Prescribed prism will pull the eyes in different directions, or assist in fusion. When you "take the EQ" (I've never heard it called that, btw) you say you read at the prp and send the measurements to the lab. You're reading intentionally ground yoked prism, done to make the lens thinner. Patients rarely are bothered by yoked prism. This isnt the same as prescribed prism, and if you don't want to induce vertical imbalance, you must send those measurements to the lab as well.
On to the next issue: is it a very small amount of horizontal prism, prescribed in only one eye? If it's a significant amount, you can split it between the eyes, and this will rid you of the need to "take the EQ" since you'd be replacing both lenses.
Hope this helps. If not, clarify for us.
Wes
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
yes, that was very helpful, I'm surprised that you haven't heard the term "take the EQ" before, maybe its a California thing?? Anyway, in the past we have had pts complain if they had just one progressive lens replaced and even though there is only a small amount of imbalance (if the EQ wasn't taken)it was enough that the pts could not tolorate. I understand about splitting the prism, thanks for that suggestion too. So, in your office when ordering just one progressive lens, do you measure the prp or EQ in the non replaced lens?
Absolutely. You measure the non replaced lens and the replaced lens. Suppose there was a minor imbalance in them to begin with, and you sent the measurements in for the replaced lens. You're now ORDERING an imbalance.
If you only measure one, measure the non replaced lens for a better match. That's the lazy way to go. I'd measure both. Reason is, if there were an imbalance, you may want to talk to the pt about it, and let them know to expect to notice a slight change. If it were very significant, they would have noticed immediately. As you noted, patients tend to be very intolerant of vertical imbalance.
Wes
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
One of your opticians is very wrong. Most progressives done by competent labs will do prism thinning with yoked prism. Yoked prism displaces light equally in the same direction, so rarely noticable in smaller amounts. Prescribed prism is used to alleviate diplopia, phorias, etc...
Wes
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
Well........................looks like you got yourself quite an issue!
What is the experience of these so called "opticians"?
You claim to be a "dispensing optician".
What do you think?
What screening process do you have for these so called opticians?
Why would you trust what we say....when you have these 4 so called opticians working for your practice?
Does anybody in that practice really know what they are doing, or are they all actors in one bogus BS play?
Why would you believe us?
Last edited by Fezz; 08-18-2009 at 08:28 PM. Reason: BOGUS BOGUS BOGUS BOGUS
Do you have any in office training?
Do you have anybody in that office who knows anything about ophthalmic dispensing?
I guess that it is just a "California thing"!
Now, now Fezz. Easy with the badmouthin of opticians.
They can't all be as good as you, or as perfect as I.
Chip
Chip, "Perfect people tend to be Crucified."
Three nails, please.
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
All in good fun guys...
Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA
“As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein
EQ = equi-(equal?) thinning = prism-thinning.
Yes, we must always determine if the lenses have been prism-thinned, regardless of the presence of prescibed horizontal prism, so that single lens replacements will not have vertical prism imbalance, or an incorrect amount of vertical prism when there is prescribed vertical prism.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Of course you need to match the prism thinning on a 1/2 pair of PAL lenses. But who came up with the EQ label? I can go with that...but, not a common term! Even in CA!
I brought this issue up at work and almost lost my head for it. Apparently, this office had been dispensing single progressive lens orders for "years without any problems." Guess how frequently people were walking around with vertical prism? (often)
However, when I posted about this on optiboard, a few people made a good point: prism thinning is determined by the add power so theoretically, if the add is the same in both lenses (which it usually is), the prism thinning will be the same.
This is where my understanding starts to fail me...it seemed to happen especially with post cataract patients, where the old script (in non-operated eye) was a significant correction (2D or so) and the new script for operated eye was virtually plano. Without fail, these jobs seemed to result in vertical imbalance. I understand the issue of deviating from the OC with unlike powers, but when looking at the PRP on a progressive, you're essentially looking at the OC, right?
Anyway, I was taught old skool style, I guess, always order both, then do an Rx change when the other eye is operated on. Seemed to eliminate a lot of remakes or "dispense and see if the pt notices" sort of situations.
A little harsh don't you think??? I ask because I value the opinion of other people that may have had more experience than I in the optical field. I did not ask to be bashed on, what a jerk. And yes, we have people that know what they are doing, however, certian issues arise that we as an office sometimes disagree on. So, rather than open MY mouth and sound like an idiot because I'm not 100% sure that MY answer is right I wanted other optical professionals opinions.
I have an article about "how to take an EQ" That is where the term comes from.
Thank you for the apology. It's hard to find other opticians in my area (ABO certified at least) to be able to bounce questions like this off of so I appreciate that Opti board is here so I can at least "talk" with other professionals and get opinions.
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