I would venture to use the distance PD,
anybody feel differently?
maybe midway between DPD and NPD.....?
I would venture to use the distance PD,
anybody feel differently?
maybe midway between DPD and NPD.....?
I would say ok depending on the seg height.
"Coimhéad fearg fhear na foighde"
You are talking about seg height and then discuss PD. My guess is you want PD....:)
Measure how far the intermediate is and set that on your CRP. For example, 30 inches would be 76.2 cm. 36 inches would be 91.44 cm. To convert inches to centimeters 1 inch = 2.54 cm so simply multiply the number of inches by 2.54 and you would have your number to set on the CRP.
Diane
Anything worth doing is worth doing well.
Good God ! And these people dispense and they can't communicate an intelligible idea ? What is it that you would be venturing to use the distance PD for ? Are you asking for the proper PD to set the near to when you mount the lenses into the frame ? Or are you asking what the seg height should be based on the PD ?
Either way you need to go back to school and should not be dispensing.
Diane , what kind of help are you giving by guessing what this person is even trying to ask ? Lets get back to basics and fundamentals here .
Teach the person to think and communicate first, you can't second guess this stuff .
No wonder half of you are not licensed ,,,, there is no intelligence here to license.
Originally Posted by idispense
Have a beer buddy!!
assuming you drank the beer.....
please excuse the misprint. I am asking which pd to block with given the lower segment is not for reading rather for intermediate.
FYI......I am licensed
Where is the dislike button. My personality is to try to help someone. There may not be any for you. So sorry that you are in an ivory tower.
Diane
Anything worth doing is worth doing well.
thanks!
I understood Jonah completely, as did Diane...his question was a valid one...
"Coimhéad fearg fhear na foighde"
Put the PD at 1mm more narrow than distance PD (each eye). Put the seg. ht. at bottom iris like you would on the intermediate of a 7/28. Unless you have determined some special conciderations.
Chip
thanks!
I do the same as I do on SV computer glasses, I turn the dial on my Pupilometer half way between infinity and reading. Take PD.Have a beer buddy!!
assuming you drank the beer.....
please excuse the misprint. I am asking which pd to block with given the lower segment is not for reading rather for intermediate.
FYI......I am licensed
In the cases where I only have distance and reading, I just split the difference, usually 1 mm less than distance PD in low powers. 2 mm less in higher powers.
No Ivory tower here Diane , but that was the poorest wording of any question I have seen recently .
What do you have to do to get licensed in New York ? How long is the course ? How many fitting hours are required?
wow!
My apologies to all. I do appreciate the desire of everyone to help and assist.
On a serious note though what does it take to be licensed in New York ? Ours was 2 years in college plus 1000 hours in the field and a prescribed number of fittings. What is the requirements in your licensed states ?
Aside from the classes, there are 2 semesters of dispensing. Dispensing ( at least the way I was taught ) includes being able to converse with patients/customers in a friendly manner.
So here's my question:
Do you actually have a successful dispensary? I cannot imagine how anyone can listen to you as a professional.
in any case .....you're forgiven
Here's the formula needed to determine the near PD.
NPD = DPD - DPD/1+W(1/s - F/1000)
W is the work distance in mm, s is the stop distance (the distance from the eye's center of rotation to the corneal plane, plus the vertex distance, typically 14mm and 13mm, respectively), and F is the lens power.
Here's a nice shortcut if the work distance is 40cm or less.
If stop distance equals 27mm, the near multiplier (x DPD) for a work distance of
40cm is .937
35cm is .928
30cm is .925
25cm is .903
20cm is .881
More decentration (for plus power) or less decentration (for minus power) may be necessary if there is sufficent power on the horizontal meridian.
Hope this helps,
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.
Aside from the classes, there are 2 semesters of dispensing. Dispensing ( at least the way I was taught ) includes being able to converse with patients/customers in a friendly manner.
So here's my question:
Do you actually have a successful dispensary? I cannot imagine how anyone can listen to you as a professional.
in any case .....you're forgiven
How many classes are there and over what length of time ? What subjects do you cover ?
I'll accept your jab as being quite fair :
"I cannot imagine how anyone can listen to you as a professional."
It seems fair to accept this from you as I purposely gave you some shock value to make you think about how poorly worded the question was .
Yes other opticians can fill in the blanks and figure out what you should have said.
Other members figuring out what I meant to ask does in fact indicate the validity of the question. YES, you are correct in your grammer check but then again your line"And these people dispense and they can't communicate an intelligible idea" does not quite reveal the english professor in you!
Back to work.
You know, in all fairness you did cross the 2 lines totally! seg height is totally different from PD & really I can reread it all day, but I can only take a guess that you were talking about PD because your title says seg ht.
EX.
PD 64/60 intermediate 62 pd.
Height fit as a normal st28, at lower lid margin, ummm, generally 3ish below.
nytol
sominex
Eyechic: Bifocal segs are normally at the lower lid unless the patient has been miss-fitted for years and gotten use to lower height. Intermediate (as in trifocals) segs are usually set at the bottom of the pupil.
You will find that people that have the intermediate set at lower lid or lower, have to hold reading material so low that they are getting help holding the book from Victoria's Secret.
Chip
yes trifocals are fit at the bottom of the pupil, but he's not using a trifocal, he's using a st28. It a matter of opinion as to why we fit the trifocals at the bottom of the pupil to begin with. I don't think we fit trifocals high, at the bottom of the pupil simply because it's an intermediate Rx. I think we fit the trifocals at the bottom of the pupil so that everything naturally falls into place. Fitting a trifocal at the lower edge of pupil will naturally throw the full reading at the lower lid margin.
I would not fit a st28 at the bottom of the pupil just because it's an intermediate RX. The only reason I'd fit a st28 higher like that would be because, like you said, that's more what he was use to.
"You will find that people that have the intermediate set at lower lid or lower, have to hold reading material so low that they are getting help holding the book from Victoria's Secret." Quote from Chip
Yes, in a trifocal, it does throw reading too low. But there is no reading in this lens in question. Your talking about holding a book. Holding a book is 40 cm, not intermediate. Forget about the book, he's not trying to help anyone read a book with the lens in question. He's trying to get the bottom portion of the lens to focus on the computer, interm, luke warm...zone.
It's all good, we're just not on the same page I guess.
wowwwwww ...... someone needs some optical anger management courses ... serious unnecessary amounts of hostility man.
"what i need is a strong drink and a peer group." ... Douglas Adams - Hitchikers Guide to the Galaxy
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