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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 ;)

  4. #4
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    Hi,

    I would appreciate help regarding GBASE / GCROS. Can somebody explain what generator base curve and cross curve are (for what are they used)? And how should they be calculated?
    Are these parameters dependent on some other parameters and what parameters should be used in calculation (FRNT / BACK ... ) ?

    Thanks in advance,
    Tijana

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