Introduction of new a Primary and Secondary Reference Points (PP and SP) based on ISO 13666-2019


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The norm ISO13666-2019 introduces new reference points for the power-variation lens (lens with a variation of focal power without discontinuity). The first is the called the primary reference point [PP]. It’s the point on the front surface of the lens where the verification power is controlled. The second point is called the secondary reference point [SP]. It’s the point on the front surface where the variation power is controlled. The variation power is the difference between the focal power at the primary and secondary reference points.

Based on that, A&R would like to introduce these new reference points (PP and SP) with its own coordinates from the ER => ERPPIN/UP and ERSPIN/UP.

Check the attached document '20240911_Introduction_of_PP_and_SP.pdf' for more details.

20240911_Introduction_of_PP_and_SP.pdf

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