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    Ask and ye shall receive. 11107 As Barry...

    Ask and ye shall receive.

    11107


    As Barry noted, there are really two applications of vertex distances:

    1. Compensating the prescription powers for the difference between the fitted and...
  2. Just some food for thought, or maybe playing...

    Just some food for thought, or maybe playing devil's advocate... While it may be technically correct that removing the Z87 markings from the frame precludes the need to install Z87 safety lenses,...
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    It isn't possible to measure the base curve...

    It isn't possible to measure the base curve accurately, although you could probably at least get in the ballpark. So, you couldn't use the measurement to do lens calculations, but the measurement...
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    Hi Robert, At 19 mm and higher, the corridor...

    Hi Robert,


    At 19 mm and higher, the corridor length remains the same. The near reference point distance is 18 mm and the corridor length to 85% of the add power is 14 mm.


    Individual 2...
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    A typical LCD computer monitor produces a...

    A typical LCD computer monitor produces a brightness of about 250 cd/m2. The sky at midday produces a brightness of 8,000 cd/m2, or 32 times as bright. The disk of the sun can be thousands of times...
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    ZEISS Individual has a variable corridor length...

    ZEISS Individual has a variable corridor length based on the fitting height, down to a height of 13 mm. You can also order the Individual 2N (Near), which has a slightly shorter corridor length than...
  7. The width of the intermediate zone is primarily...

    The width of the intermediate zone is primarily constrained by 1) the corridor length and 2) the add power. If the wearer has had an increase in add power, you can expect the intermediate zone to be...
  8. You guys might find the attached troubleshooting...

    You guys might find the attached troubleshooting guide handy.

    Best regards,
    Darryl
  9. No, you would just adjust the dominator for the...

    No, you would just adjust the dominator for the shorter testing distance. The numerator would stay the same. If you want to convert the whole thing to the more common notation using 20 feet in the...
  10. At half the distance, the letters are effectively...

    At half the distance, the letters are effectively twice as large for a given line of visual acuity, so the visual acuity would be half as good (you would double the Snellen denominator). So the...
  11. What is her prescription? Best regards, Darryl

    What is her prescription?

    Best regards,
    Darryl
  12. We don't currently publish any specific claims...

    We don't currently publish any specific claims against Crizal AR coatings.

    Best regards,
    Darryl
  13. The limitation of specialty bifocal styles in...

    The limitation of specialty bifocal styles in Transitions lens materials is due mainly to economics: There is very low demand for products like round seg bifocals, so it may not be cost-effective to...
  14. I'm afraid that you've been misinformed. PureCoat...

    I'm afraid that you've been misinformed. PureCoat PLUS utilizes a new top coating formulation that delivers longer lasting cleanability over the life of the prescription.

    PureCoat PLUS also...
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    On a completely unnecessary side note, while...

    On a completely unnecessary side note, while Ray-Ban sunglasses were obviously developed originally by Bausch & Lomb, the sunglasses initially offered by Randolph Engineering were developed...
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    MakeOptics has done a nice job describing the...

    MakeOptics has done a nice job describing the technical nuances involved. The bifocal segment acts like a small plus lens affixed to the distance lens so, above the segment center, this prismatic...
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    I am not aware of the use of the designation...

    I am not aware of the use of the designation "Master Optician" outside of 1) ophthalmic dispensing and 2) precision optical fabrication. As far as I know, a "Master Optician" in optical fabrication...
  18. Thread: Zeiss

    by Darryl Meister
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    No offense taken, Peter. While I do frequently...

    No offense taken, Peter.

    While I do frequently speak to the technical aspects of ophthalmic optics, my previous post presents independent data for how the lenses have actually performed in real...
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    I no longer make my old Optical Analysis program...

    I no longer make my old Optical Analysis program available, because I have replaced it with the much more useful Spectacle Optics program, which you can also download for free.

    Best regards,...
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    The final processor is still required by law to...

    The final processor is still required by law to at least perform (and document) batch testing of plastic lenses in their finished form...

    Best regards,
    Darryl
  21. Thread: Zeiss

    by Darryl Meister
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    The basic "fingerprint" of semi-finished ZEISS...

    The basic "fingerprint" of semi-finished ZEISS GT2 relies upon the same lens design platform as free-form ZEISS Individual, so I would certainly not expect any more issues with ZEISS Individual...
  22. Thread: Zeiss

    by Darryl Meister
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    32,905

    Your past experiences in Europe with the original...

    Your past experiences in Europe with the original ZEISS Individual may not really be indicative of what current users of ZEISS Individual 2 should expect in North America, due to differences between...
  23. Thread: Zeiss

    by Darryl Meister
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    32,905

    RVT? Would you mind clarifying the time period...

    RVT? Would you mind clarifying the time period are you referring to in your post? ZEISS Individual has improved quite a bit over the years. For that matter, we actually use a slightly different...
  24. Thread: Zeiss

    by Darryl Meister
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    50
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    32,905

    Yes, fitting ZEISS progressive lenses "low" (that...

    Yes, fitting ZEISS progressive lenses "low" (that is, below the recommended guidelines that all lens manufacturers currently use, which is to pupil center) will unnecessarily compromise intermediate...
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    Although the interaction between blue light and...

    Although the interaction between blue light and the chromatic aberration of the eye is an important consideration, I think the concern of the original poster was with the potential for long-term...
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