Ok so to start with the Rx
OD +2.75, 4.5 BI prisim
OS +2.75, 4.0 BU prisim
But the doctor also wrote "ground-in prisim only"
We did 2 pairs of glasses, and the doctor says we did 1 right and the other isn't ground in - it's decentralized. I was under the impression that so long as it's done correctly (which from my reading of the Rx and our lab's as well after double checking it) that it ammounts to the same thing. Am I missing something? I feel like I am.
Bart Smith, continuing to be awesome since 1982 so that you don't have to.
Love is a duet, each voice complementing each other and making them sound better than they would alone, each voice at times stepping back and letting the other shine. We've got a pretty good duet going Tina.
On April 28th, I'll be marrying my best friend. I can't wait!
That amount of prism will look much better ground in, optically and aesthetically.
It's "decentered", not "decentralized", but "induced" is better.
Please ask the doctor to describe to you the method by which he concludes that the prism in the one pair is induced and not ground, and share it with us.
Could this be something like feed yourself with your right hand or feed yourself with your left hand. What would be the diffrence as long as you could feed yourself? After all it is the end result we are looking for isnt it.
But yes, depending on the size of the frame and the amount of prism and the PD some jobs will look much nicer if the prism was ground.
Obviously, edge thickness may be an issue; but that's true whenever you use a finished lens of more than trivial plus power. But the question was about "grinding prism", not about using a surfaced vs. a finished lens. One could surface a lens to the appropriate thickness, with no prism, and then induce prism by decentration, and end up with exactly the same edge thickness as with a lens on which prism had been ground.
A rose by any other name still smells as sweet.
My guess is that one pair had a greater minimum thickness, strongly suggesting, but not assuring that the lens was decentered to induce the Rx prism.Originally Posted by shanbaum
opticianbart- a +2.75 should almost always be surfaced to achieve an optimal minimal thickness, prism or not, and/or if the surface design is aspheric/atoric (with Rx prism).
Last edited by Robert Martellaro; 07-13-2012 at 01:19 PM.
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.
Apparently the Dr. comes from the school of "it's the optician's fault" I've since been given a slightly different Rx in the left eye. Apparently the Dr. told them we'd made it wrong and then given them a new Rx sheet, but they didn't bring it in because they assumed we already had it.
Bart Smith, continuing to be awesome since 1982 so that you don't have to.
Love is a duet, each voice complementing each other and making them sound better than they would alone, each voice at times stepping back and letting the other shine. We've got a pretty good duet going Tina.
On April 28th, I'll be marrying my best friend. I can't wait!
Kind of reminds me of an old EENT man who used to say: "I'm not a prism man, can't you do it with decentration." I might add that he was the best eye muscle surgeon ever.
Chip
I LOVE IT!
They made wrong and by the way give them a totally different RX while they changing the lenses at their expense!
That deserves two binocularly placed pies, doncha think!!!!!
Eyes wide open
Was there any reason given for not splitting the prism for cosmetic reasons?
2.87 base down and in @321 degrees OD and 2.87 base up and in @ 141 degrees OS looks a lot better than:
4.5 BI prism OD
4.0 BU prism OS
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
Usually no, but it is wise to consult with the prescriber. There are times when splitting it is not the wisest course of action for certian conditions.
Chip
No reason was given. However the frame in use is small enough that there isn't too much thickness - especially after using poly.
I've run into a few cases where Doctors have written "do not split prisim" before, what kind of conditions make it so the prisim shouldn't be split?
Bart Smith, continuing to be awesome since 1982 so that you don't have to.
Love is a duet, each voice complementing each other and making them sound better than they would alone, each voice at times stepping back and letting the other shine. We've got a pretty good duet going Tina.
On April 28th, I'll be marrying my best friend. I can't wait!
I don't know what conditions should not be split. I do know some very skilled OMD's that do and can find out if you really want to know. However from an opticians standpoint, those that should not be split are those that the prescriber says: "Do not split prism."
Chip
I would like to know the reasoning for when you can, or shouldn't split prisms.
I love the "it's the optician's fault" mentality...not too long ago we made a pair of glasses for a patient that included prism. A few days after we dispensed them the patient returned angry with a page long hand-written letter from his ophthalmologist (which included some very amusing spelling errors) accusing us of making the glasses incorrectly because....wait for it....the eye size in the new frame was 1 mm different than is previous frame. Needless to say there weren't any frame measurement specifications on the written prescription provided to us initially. Love it!
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