Shamir Office O-PAL for distance use: over minusing Dist. RX

[sr20bet]

45 year old female patient currently using traditional progressive lenses. She spends approx. 10 hours a day engaged in near visual tasks for vocational reasons; 75% computer, 20% reading and 5% for distance (to view 25ft). Assuming that the distance rx is -6.00 OU with an ADD of +1.50 (in this case).

I would normall use a HOYA Tact lens for those that require full distance rx, however I am trying to experiment with lens designs that may provide a wider field of view at near and intermediate viewing distances. I'm considering using the Shamir Office OPAL. With the Shamir Office lens, a +1.50 add will yeild a dynamic power of 1.25 at the top. Thus, the distance rx would have an effective add of +0.25.

I'm considering over-minusing the distance rx. by 0.25 (-6.25) while using a +1.50 ADD (effective add reduced to a total of +1.25), however in theory the distance rx would have an effective add of zero (0) in hopes of aiding her requirement for distance vision in her vocational environment.

Have any on this forum taken this approach? thoughts? experiences? warnings?

Thank you in advance for all responses.

[waxend]

You should feed the Rx to the lab as Dst.-6.25ou Add 1.50. Your total power at near reference will be -4.75 ou. Now on the Office you need a minimum of 16mm above MRP for any benefit of a distance Rx, and 13mm below MRP for near. This will work, only if the patient is just gazing of the top distance portion, like in an "Office" environment. Now, will a 0.25 make that much of a difference? Also check with Shamirlens for add availabilities in their Office product, their regressive nature makes these adjustments tricky.

[Christosfer]

You should feed the Rx to the lab as Dst.-6.25ou Add 1.50. Your total power at near reference will be -4.75 ou. Now on the Office you need a minimum of 16mm above MRP for any benefit of a distance Rx, and 13mm below MRP for near. This will work, only if the patient is just gazing of the top distance portion, like in an "Office" environment. Now, will a 0.25 make that much of a difference? Also check with Shamirlens for add availabilities in their Office product, their regressive nature makes these adjustments tricky.

I think you have the measurements reversed, it's 16 below MRP and 13 above, but will go with 10. The adds are .75, 1.25, 1.75 (not available in poly forever), and 2.25.

[k12311997]

I think you have the measurements reversed, it's 16 below MRP and 13 above, but will go with 10. The adds are .75, 1.25, 1.75 (not available in poly forever), and 2.25.

you are right with the 16 and 13 but if you only allow 10 above MRP you will lose whatever distance you get.


sr20bet
I'm not looking at my litature right now I think with that Rx your looking at a max distance of 3 to 5 feet you couldn't get 25 feet out of that in any office lens that I'm aware of

[sr20bet]

you are right with the 16 and 13 but if you only allow 10 above MRP you will lose whatever distance you get.


sr20bet
I'm not looking at my litature right now I think with that Rx your looking at a max distance of 3 to 5 feet you couldn't get 25 feet out of that in any office lens that I'm aware of

Hoya Tact OPAL give full distance rx at the top (chin down), but the fov are not as wide.

[k12311997]

Hoya Tact OPAL give full distance rx at the top (chin down), but the fov are not as wide.

not familiar with the Tact thank you for the info. at work now I was a little short on distance a +1.50 add with the -1.25 Dynamic power yeilds optimum distance vision of 13.5 feet.

[sr20bet]

not familiar with the Tact thank you for the info. at work now I was a little short on distance a +1.50 add with the -1.25 Dynamic power yeilds optimum distance vision of 13.5 feet.

thanks for the feedback. appreciated.

[nicko]

Prio has a neat little program called the Shazam. You plug in the numbers and the program will give you the respective powers in dist, near and intermediate. You can let the program pick the lens and the "Prio add" automatically or you can choose to input manually. The program will apply to the Office lens as well because the regular Prio lens is the same.

If you wish to input the data yourself, the rule of thumb is to take half the add power and add a quarter for the "prio" add. You can change lens designs and regular add powers and see what the resulting lens will give you. Make note that it does not calculate anything, but only give you what the lens will be under the parameters you select.

For every change you make, it will change the other areas of the lens. For example you can start with a Prio (office) 1.25 and run it as automatic and look at what the powers are. Write them down and bump the add a quarter, recalculate and notice the difference. It should have less minus in the distance and more plus at near. By making an educated guess, you can customize to stretch the distance by sacrificing some of the near or conversly, try to get a true near sacrificing some distance. The intermediate (computer vision) should stay the same.

When ordering from the lab, fax the printable sheet or call it in. As far as I know, they haven't been able to adjust it for online ordering. Make sure the lab knows that you have done the calculations and order it as a single vision lens (do not give the add powers) and that way it won't get double calculated.

For more info, contact Prio directly.