Unlike Victoria's Secret, this is more technical.

Oakley labs seem to have a formula to alter a spectacle Rx so that when they make it in a "wrap" frame, there is less prism induced and less distortion of optics. I would like to know what formulae they use, so I can create the same effect when I do wrap lenses (heaven help my optical lab).

If I recall my optics correctly, there is a formula that derives induction of power by tilting on a horizontal or vertical axis (like with too much pantoscopic tilt) that is something like: change in sphere = Fsin(squared)theta/2, and cylinder is: blah, blah, blah. (I know these are not the actual equations, and I can look them up. My question is theoretical, more than needing to have the formulas just yet.)

I would assume that since the formulae can compute change of power in the horizontal meridian with lens tilting on a vertical axis (frame wrapping, I contend), the general concept would be to combine the spherocylindrical change with the orginal spherocylindrical Rx power to give a new Rx. (I would have to make an assumption as to how much angular lens tilting there is with an 8 base frame, as well, but it could be derived empirically with a protractor, but I'm guessing about 15 degrees.)

I think that there would be some prism induction as well, and I've tried tilting trial lenses of various power in the same direction as a wrap frame, and I seem to get results that are independent of type or degree of power. It seems as though any lens tilted temporally, like in a wrap frame, displaces objects temporally, like a base in prism would. I would assume that there is some formula for this based on lens thickness and degree of rotation, and not power, which makes sense, because even plano wrap lenses from sunglass companies can give this effect, and that "prism correction" is what Oakley touts even in their plano eyewear. I would assume it's on the magnitude of 1-2 pd total.

Do you brains have anything on this? I'd appreciate your general thoughts, and any formulas that may be echoing in your heads.

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