How Do I Dispense A High +6.00 Add !
HI THERE
I recently came across a patient in my training who had very unsightly glasses. She told me she was +1.00 in both eyes and had an ADD in her Bi-focals of +6.00 !!!!!
How would one go about dispensing some cosmetically appealing lenses for this patient?
what about high add executive lenses (fusing two separate lenses into a power bifocal correction)
+6.00 does seem like a low vision problem. what materials and other methods would anyone else suggest? hmm
I know both Younger and X-Cel make a ST-28 in that high of an add in CR-39. There aren't alot of options in choice of material (glass or cr-39) as far as I'm aware of. There are one or two available in the ST-35 or 7x28 in that high add. What is this patient currently wearing? And do they look that bad?
The least expensive way and no much less appealing cosmeticly is a Franklin bifocal (split and do not fuse two lenses, If you fuse them glare from seg. line will be intolerable). Other alternatives are specialty made items which take forever and cost a bunch.
Note: With this much difference you might concider adding some thickness to distance in order to get the demarcation line from being quite so prominant.
Chip
well i came across her and the bifocal seg bit just looked 'ODD' in the fact that it stuck out and was very unsightly. How would be the best way to dispense this prescription if she came into your practices?
Unless you can get a fused glass lens, or a progressive (which she won't be able to see trough even if you get it) the seg is gonna stick out a lot, or if you play games with base curve and thickness in a Franklin, you might be able to get the seg tangent or near tangent centrally and have a pretty good edge (distance overhang, peripherally).
Chip
Of course, you could get one of the specialist labs to cement a small 18 or 22 round wafer of +6.00 to a single vision lens, I've done a few like this with prism and the cosmetic appearance is just fine
Thanks Ziggy, I had forgotten about these, probably because I don't know anyone in a lab that can grind a wafer. The old beer drinking derilicts in out house lab back in the '60's had no trouble doing this. I do remember that if done in glass it can be cemented with Canadian Balsam and removed after soaking in Xylenes.
Chip:cheers:
I think there is a better way.
A +6.00 spectacle magnifier should not be put in a bifocal in the first place. Sure, make a pair up to +3.50 TF for general purpose use. But when the person really needs to see to read, they need to have a half-eye set up.
That's the way it's really done in low vision.
Not only that, but she'd need some prism, up to 6^ BI to help her convergence. The working distance of a +6.00 is 16cm (6 inches)! Try converging your eyes to that distance for 30 seconds without a headache! And you can't have that prism in the distance portion of a multifocal, of course.
Bad idea in the first place. You can relax and "fuggedaboudit".
Just wanted to agree with drk. A +6.00 add is not a great idea and is not the way it is usually done in the world of Low vision. Readers with BI prism are much better or a magnifier.
Bummer that the prescribing doc didn't go this route, now it is your problem to deal with. :hammer:
Hi Chip, when you referred (above) to Ziggy, were you talking to me?Originally Posted by chip anderson
I only ask because that was my late father's name and it just made me jump to see it in writing!
Two pairs of single vision lenses?
Not sure if you are referring to me and drk's posts but the answer is no if you are. One pair of bifocals with a high-normal add (like a +3.00), and a handheld magnifier would be a common recommendation. High plus readers with BI prism would be available for longer periods of near vision tasks such as reading the Bible (common one) or newspaper.
nope - that was my response showing a posibility for dispensing the said script..
lets think about why the script is rescribed, and what working distance we are talking about.. I might even go so far as to say a half eye would be a good idea - in the mix
I thought there is a way to make a prism in the segmented bifocals.
The person will have BI in NV only!
I think it cost a fortune!
Lenny, read my first post on Franklin Bifocals, you can do all the above with or without prism. Prism can be in bottom only, both, diffent both portions, even in different directions. Not expensive, should require no more lab time than 2 single-vision jobs. Should take about an hour and half of your time on your first job of this type. Your cost should be exactly as much as two pairs of single vison lenses with possibly an add on for prism. NO distortion as present in any type of fused bifocal.
Chip
Lenny,
There are two ways to get that prism in the NV only on standard segmented bifocals. The one that is typically used is to decenter the seg during surfacing to create the prism in the segment only. Doing this the lab would calculate the decentration needed to create the prism, as drk noted up to 6^ BI in this case. If a patient had a pd of 63/60 and you had this Rx and was wanted 6^BI in your seg only, the resultant pd for surfacing would be 63/43 (seg decentered 8.5mm each eye). The problem with this is when edged you pretty much cut off half of the seg since it is decentered so much. I really don't think this would be a good solution. The other solution using a traditional segmented bifocal for getting prism in the seg only on is what Clive spoke of in a cemented seg. Just grind the prism into the seg being cemented, keeping the full use of the seg unlike the other option. I think that I would agree with a number of the other posters thought that a traditional flat top bifocal isn't the best solution. Suprised we haven't seen Jacqui add to the conversation, with talks of Franklin Bi's, by chip etc I would think she would have an idea or comment.
(I'm not an expert on surfacing so if I was way off on my explanation to Lenny's question above, someone please correct me.)
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