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3 Cards in this Set
- Front
- Back
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Define nominal surface power |
This is the (uncompensated) surface power which would be worked if the lens were to be considered to be infinitely thin. |
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Define compensated surface power |
This is the actual (reduced) power which needs to be worked taking the thickness of the lens into account. It's is always more NEGATIVE than the nominal value. |
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Define vertex power allowance |
This is the difference between the compensated and nominal surface powers. It is ALWAYS A NEGATIVE VALUE. |
