Questions about horizontal prism and PAL's....

[fortheloveofframes]

I remember taking a class regarding this subject. I have a pt the has 4 diopters of BO prism and my doc rx'd a progressive and I don't know why but I have just been dreading her specs coming in because I just am not sure how that much prism with a progressive is going to work out. ANY HINTS? Comments or suggestions??:hammer:

[Wes]

If you've already ordered them this may not help... but if you have a remake, it will.

In System for Ophthalmic Dispensing, Brooks & Borish recommend compensating your pd measurement by roughly a third of a mm toward the apex for every diopter of prism. Depending on vertex dist and the pts ocular anatomy it can range from .25 to .33 per diopter. I would adjust the pd on this by 1 mm less than measured per eye. Also, always use a high abbe material when working with prism. Never use poly with over three diopters of prism.
This is specifically recommend for progressives so that the eye tracks down the corridor but useful in all lenses, especially aspherics with large quantities of prism.

[Wes]

http://www.optiboard.com/forums/show...se-Out-per-eye
Read this, esp the posts by Harry Chiling, Robert Martellaro and Lensgrinder.
Good luck.

[fortheloveofframes]

Thank you so much for the help. They should be coming in today.

If you've already ordered them this may not help... but if you have a remake, it will.

In System for Ophthalmic Dispensing, Brooks & Borish recommend compensating your pd measurement by roughly a third of a mm toward the apex for every diopter of prism. Depending on vertex dist and the pts ocular anatomy it can range from .25 to .33 per diopter. I would adjust the pd on this by 1 mm less than measured per eye. Also, always use a high abbe material when working with prism. Never use poly with over three diopters of prism.
This is specifically recommend for progressives so that the eye tracks down the corridor but useful in all lenses, especially aspherics with large quantities of prism.

[Craig]

One of my largest clients is a -4.00 with 6D BO OU in a +2.25 add and he has no problems. We use 1.67 because we do drill-mounts for him most of the time. He did order 3 more www.superfocus.com yesterday; he already has one pair. He likes having complete lens optics as compared to what he is wearing for some tasks.

I make sure we get them fit perfectly for him and what advantage would he gain by moving the pd's? He will try anything and he just broke a pair we need to re-do anyway.