Results 1 to 16 of 16

Thread: Digital surfacing. (There, I said it.)

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    9,407

    Digital surfacing. (There, I said it.)

    This is the only place in the world to discuss this.

    Ok, so I have been told by someone who should know (wholesale lab rep) that digital surfacing is better than traditional surfacing.

    I saw some pictures of the process, and it looks like "a needle" cuts a rotating lens.

    Why is digital surfacing better? Because complicated surfaces can be cut that minimize abberation (I believe). The back surface of a digitally surfaced spherocyl may not be the "inside of a teaspoon" shape, but something that resembles a landscape with rolling hills (very, very, rough, there).

    Why is digital surfacing better? This may be something I imagine I heard, but, similar to how progressives are designed with ray-tracing to correct the off-axis powers at different angles of gaze, this technology can be applied to the design of higher power SV lenses, as well. Does anyone know if I'm even close on that one?

    Why is digital surfacing better? Whether digitally surfacing a mold for the front surface of a progressive, or surfacing an actual lens, the process itself is "cleaner and more precise".

    The question is: how much better, and who will perceive it? We may be in a transitional state where we need to identify who will benefit from these incremental improvements, until it becomes commonplace.

  2. #2
    ATO Member HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,765
    This is just opinion, but I think just the digitally surfaced part doesn't amount to a hill of beans. The true improvements come in the design of the lens. If the lens is digitally surfaced to a spherical shape than you just took the long way home thats all. If the lens surface is freeform and this change in form is optimized to rid certain aberations than you have something and I think even in this case, the people that are going to truly notice is the ones with higher cyl's, higher powers, and oblique axis's.
    1st* HTML5 Tracer Software
    1st Mac Compatible Tracer Software
    1st Linux Compatible Tracer Software

    *Dave at OptiVision has a web based tracer integration package that's awesome.

  3. #3
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    9,407
    I think that's a pretty good point: that the main advantage of digital surfacing technology is the ability to "do more" with lens design.

    Anyone heard about the "abberation controlled SV lens" concept?

  4. #4
    ATO Member HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,765
    I have heard of the i-zon I think it is called that is supposed to eliminate or reduce aberation, I haven't actually seen the lens or even heard any feedback about it. I understand the concepts and how they work, but like you said I would love some feedback as to if the lenses make a difference. It should slowly unfold in the near future as everone seems to be rushing to have a free form lens.
    1st* HTML5 Tracer Software
    1st Mac Compatible Tracer Software
    1st Linux Compatible Tracer Software

    *Dave at OptiVision has a web based tracer integration package that's awesome.

  5. #5
    Allen Weatherby
    Join Date
    Jun 2004
    Location
    Florida
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    1,286

    Digital Surfacing

    drk said:
    Why is digital surfacing better? Whether digitally surfacing a mold for the front surface of a progressive, or surfacing an actual lens, the process itself is "cleaner and more precise".
    The above statement is correct however both glass and metal molds have been made by digital surfacing for years. The lens manufactures are using this term to imply new precision lens production. In many cases these lenses are produced the same way as the previous lenses produced.

    Harry said:
    The true improvements come in the design of the lens.
    This is the benefit to digital surfacing.

    I do not have the space here to explain all of the advantages to digital surfacing lens designs.

    I will site one example: A plus PAL lens, with the PAL design cast on the front of the lens that requires a 2 base back curve will have an edge thickness for a 50mm A dimension that is quite thick. This edge thickness can not be smaller because the front design must work for all A and ED measurements even a 60mm or more. An individual digitally surfaced plus lens of the same power can have most of the abberations removed with a complex design. This design can be made for the smaller 50mm A measurement frame and a big percentage of lens weight can be eliminated by this digital surfacing in addition to wider usable lens area.

  6. #6
    Master OptiBoarder Darryl Meister's Avatar
    Join Date
    May 2000
    Location
    Kansas City, Kansas, United States
    Occupation
    Lens Manufacturer
    Posts
    3,700
    Keep in mind that "Digital surfacing" isn't a process; it is just one particular manufacturer's "branding" of a relatively common process.

    All modern generators are "digitally" (CNC) controlled, and many use a single-point turning process. The main advantage to the use of a "free-form" generator is the ability to produce complex surfaces with a high degree of accuracy and smoothness. This is important because hard lap fining and polishing cannot be used on complex surfaces, and soft lap polishing can distort the shape of the surface with extended polishing (this effect is dependent on the shape of the part).

    However, as Harry and Allen pointed out though, this doesn't really offer the final wearer any meaningful benefit over a traditionally surfaced lens unless the process has been used to create a unique, individualized lens design based on factors specific to the wearer (including modifications to the design based on the prescription, fitting measurements, and so on). If you use a free-form generator to produce a basic toric -- or even progressive -- lens design, you really aren't achieving anything that a traditional lens couldn't deliver.

    Further, while free-form generators arguably replicate a lens design more accurately than casting (which I would consider a relatively robust and repeatable process), the free-form process must be very carefully engineered to ensure that the final product maintains good form accuracy after soft/flex polishing. Just because the lens looks good off the free-form generator, doesn't mean that it will look good at the end of the process.
    Darryl J. Meister, ABOM

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Digital Refractor
    By amoura_0 in forum General Optics and Eyecare Discussion Forum
    Replies: 2
    Last Post: 03-24-2006, 09:42 AM
  2. Digital Retinal Camera
    By drdon in forum General Optics and Eyecare Discussion Forum
    Replies: 2
    Last Post: 11-05-2005, 11:19 PM
  3. New Digital Camera
    By Steve Machol in forum Computer and Software Help
    Replies: 6
    Last Post: 04-15-2005, 01:43 AM
  4. Digital Cable........Or Satellite......T.V. ?
    By Sean in forum Computer and Software Help
    Replies: 14
    Last Post: 04-08-2005, 07:16 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •