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Thread: Ideal Back Curve vs. Index

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    Idea Ideal Back Curve vs. Index

    When we say -6D is the ideal spherical back curve, does that refer to a 1.53 index lens?

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    Ghost in the OptiMachine OptiBoard Silver Supporter Quince's Avatar
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    That would be for any index. I try to strive for a -4 to a -6 while keeping in mind the frame's natural curve.
    Have I told you today how much I hate poly?

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    Quote Originally Posted by ravenclaw View Post
    When we say -6D is the ideal spherical back curve, does that refer to a 1.53 index lens?
    A back curve of -6.00 would have no reference to index. A -6.00 is a -6.00 period. The only time you would need to reference index is to determine what tool to use to arrive (surface) at a specified back curve from a given front curve if using anything other than a 1.530 index. For more info on ideal back curves you need to reference the old AO tillier lens design. Some of the older members.....I believe Mr Baker was an ex AO guy, could point you in the right direction.

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    OptiWizard
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    This should answer most questions regarding ideal curves
    https://www.2020mag.com/ce/evolution-of-single-vision

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