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Thread: Lens calculations

  1. #1
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    Lens calculations

    Hi,

    I would like to be able to calculate the GBASEX as well as GCROSX in TIND for any kind of FRNT base.

    I used the calculation for thick lenses in order to compensate thickness but the radius I find in my calculations is not ok. I still have slight difference with the rx I required.
    I first start only with a minus sphere in order to do not have to recalculate the thickness each time.

    Do you have any idea ? is there some compensation to apply

    Thanks

    Aurélien

  2. #2
    Master OptiBoarder optical24/7's Avatar
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    Are you compensating for index of refraction? Show an example calculation you’re running.

  3. #3
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    Hello,

    I am using the formula V = V1 + V2 − V1.V2.e / N to calculate V2.
    But I read some posts in your forum and I found that I have to apply back compensation. Since I did it, my calculations seems correct ;)

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