So we have this customer that wears 7X28 trifocals. She gets an exam and her RX changes by a -0.25, previously was -0.25.
She states that her vision is much better with old correction. With the new glasses she has to look through the intermediate to see distance clearly. Could the -0.25 really bother her that much?
The only thing that I noticed was the placement of the OC, with her old glasses it was around 10mm above seg line, and with new one's about 2mm above.
Please help,
Thank you,
Joa
Should be an Optiboard rule, when posing questions to give the complete RX.
DittoOriginally Posted by gemstone
It depends on how far away the object is when she says the distance vision is clearer. There's a problem with the Rx if traffic signs are clearer through the intermediate, but might be normal at two to three meters.
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.
You mentioned to difference in the OC's of the lens. Is there a difference in where the patient's pupil is located between the lens? It won't answer the question about the -.25 difference, but you have me curious.
William Walker
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Or was there vertical prism in her old pair? By default, most labs will place the OC no more than two or three mm above the seg, unless there is a ludicrously low seg height. I can't imagine a good reason for placing the OC so high.
DragonlensmanWV N.A.O.L.
"There is nothing patriotic about hating your government or pretending you can hate your government but love your country."
There are people who are very sensitive to -0.25. I would over-refract her and see how she likes it
FYI - I can guarantee you if this was a post about PALs, someone would be blaming the PAL. If it was a post about poly, someone would be blaming the material
"She states that her vision is much better with old correction. With the new glasses she has to look through the intermediate to see distance clearly. Could the -0.25 really bother her that much?"
Pretty much got to be a .75 difference between the distance and the intermediate. This appears to be a hit and run post anyway.
Yeah, maybe they should get some new 7X28 360s. Not in poly of course. :D
DragonlensmanWV N.A.O.L.
"There is nothing patriotic about hating your government or pretending you can hate your government but love your country."
If you want help please provide the new prescription and the old one too. Measure the old lenses and check the prescription on the intermediate. Some trifocals has for intermediate 1/2 of the add and others 1/3 of the add. By the way, measure new glasses too and also measure the intermediate.
Material would make a difference, there is a difference in OC of 8mm this can cause the the effects of abbe to be more evident in the lens leading to a reduced visual acuity. Of course can't tell without knowing the abbe of the material if the lens is within an acceptable tolerance. As for a progessive if the lens had what would be considered the OC surfaced 8mm lower the effect would be evident at the PRP.
With the basic info present the only thing to explore is as mentioned any prescribed prism that ay be missing from the new pair. Having the OC 10mm from the seg line of a trifocal is pretty extreme, 2-3mm seems within the norm, but again without more data this is just the best possible guess with the facts presented.
Hi to All. I am new to the group, but have reference this website several times over this year. I love it and enjoy all the feedback. Yes, without an RX, and an add, how do we know what the intermediate power is adding. Also, They have mentioned where the OC was places above the line, but not where the pupil lies, as compared to the lines, or OC. I would say the patient is definitely exaggerating. And again as another mentioned, of course she would see better at 3-6 feet out of intermediate, with a -0.25 change to distance, because it has slightly lessened her intermediate (granted the Add power is unchanged). Anyway, very happy with you all and your input. -RJ Smart, owner's kid, 26 year old (9 year) ABO from Cali!
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Sorry for the repetative, parrot nature of my post. Just wanted to make my FIRST!!!
Remake to the old rx and call it a day.
Welcome to the board!
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