Best Formula for calculating lens thickness with Prism

[Tallboy]

En lieu of a lab surfacing software package, what is the best formula for calculating lens thickness for a Prism lens?

Especially one with little or no sph/cyl power?

[Kwill212]

Harry has the answers in this thread. I wonder if he ever finished writing the program? http://www.optiboard.com/forums/show...ckness-w-prism

Also chapter 16 of Systems goes into the how and why.

[Wes]

My Excel formula for Additional thickness for prism is: =ABS(((Min Blank/2)^2*Prism Amount)/(2000*(Index-1)))/2

This shows the additional Center Thickness, and would be added to whatever the blank thickness would be without prism.

[Tallboy]

Thanks guys. Yeah I was looking at my systems book but then I got busy. I will do the math later. Really appreciate it