Results 1 to 21 of 21

Thread: How does Free-form chalenge us?

  1. #1
    Master OptiBoarder QDO1's Avatar
    Join Date
    Sep 2005
    Location
    UK
    Occupation
    Dispensing Optician
    Posts
    1,963

    How does Free-form chalenge us?

    Consider this RX, as written...

    R -6.00 - 2.00 x 45 2 base IN
    L -3.00 -2.00 x 135
    Add + 2.00
    "Please dispense progressives"
    Signed: Joe Blogs MD

    So you think about it...
    Clearly the patient is:
    Just about aneisometropic, has oblique cyls, and is a moderate myope

    A discussion with the patient confirms the need for a multi-purpose pair of spectacles - he works in a shop, selling computers, typing up orders, and serving customers all day long, and often multitasks

    In the first instance, this looks like a perfect example of a RX for free-form progressives, where the free-form optimisation, can go some way to alliviating some of the problems this type of RX poses

    What do we do next? What other info do we need from the practitioner, who is not in the building?

    So eagerly we run off and (for no other reason than its the first one to come to my mind) grab that ILT order pad the Rodenstock rep left behind

    It asks you for

    • Test BVD
    • The order and power of the lenses in the trial frame including the prisms
    • How you want the prism split up
    • How much the patient converges
    and
    • The dihedral angle of the frame
    • Frontal angle
    • BVD for the dispensed frame
    • Mono OC's
    • Mono Heights
    Now we are stuck. To start off with (to my mind) the BVD ought to have been on the original order. The other information (to do with the test) is not available. How many "regular dispensers" would struggle with the dispensing measurements.. the implication on the form, is that they want them pretty accuratally

    The industry as a whole is not set up to deal with this sort of free-form technology - and thats pre-order. This technology is what we all have, available in our practices today, and it is allready being "demanded" by patients. Some are calling them the "ultimate lenses", but at the moment, unless the refractionist is doing the whole job "from refraction to dispensing and ordering", or, if the dispenser is working hand and glove with the refractionist... the process stops

    what practitioners need to do is start recording this type of information, if they have a slight idea that this sort of lens may be used in the dispensing. what dispensers will need to do is learn how to measure all of the new measurements (that most) dont ever measure for anything

    The lens manufacturers are throwing down a chalenge to us
    Richard King
    Webdesign: http://www.placeofdesign.com
    Photography:
    http://www.kingprophoto.com

  2. #2
    Bad address email on file
    Join Date
    Jan 2003
    Location
    Folsom CA USA
    Occupation
    Optometrist
    Posts
    304
    Quote Originally Posted by QDO1
    This technology is what we all have, available in our practices today, and it is allready being "demanded" by patients.
    That's a stretch, at least for Folsom CA, a pretty high tech neighborhood (my office is walking distance from Intel's big plant-7000 geeks). I've been fitting progressives for 30 years, have a lot of progressive wearing patients, and have never had one even ask about free form techology. No doubt the use of this technology will increase (and should), but there's a LOT of inertia out there...

  3. #3
    Allen Weatherby OptiBoard Gold Supporter
    Join Date
    Jun 2004
    Location
    Florida
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    1,285

    How do you order a Freeform lens?

    First all freeform technologies do not need the same information.

    My company has developed freeform designs. We are currently developing more and to handle the ease of use for the optiician we are requiring the frame be either one of ours (ICE-TECH), or to send any other frame to us at ICE-TECH Rx. Our remommendation is to dot the pupil and submit the standard Rx. We measure the frame, make the necessary calculations and will return the completed frame and lens ready for delivery to the patient.

    Some freeform designs do not require frame angle information making them not quite as individualized.

  4. #4
    Keep on truckin... Cherry Optical's Avatar
    Join Date
    Apr 2005
    Location
    Green Bay, Wisconsin
    Occupation
    Optical Wholesale Lab (other positions)
    Posts
    639
    Quote Originally Posted by QDO1
    Now we are stuck. To start off with (to my mind) the BVD ought to have been on the original order. The other information (to do with the test) is not available. How many "regular dispensers" would struggle with the dispensing measurements.. the implication on the form, is that they want them pretty accuratally

    The industry as a whole is not set up to deal with this sort of free-form technology - and thats pre-order. This technology is what we all have, available in our practices today, and it is allready being "demanded" by patients. Some are calling them the "ultimate lenses", but at the moment, unless the refractionist is doing the whole job "from refraction to dispensing and ordering", or, if the dispenser is working hand and glove with the refractionist... the process stop
    Not to be obtose, but perhaps you should schedule an appointment with your lab rep to talk about the proper ordering procedure and fitting of Free-Form lenses. If he can not help you, I would suggest firing him and calling someone else who has spent time learning about new technology.

    All labs are not equal. Most do a great job of making the same lenses they have been making for the past 100 years. Few have taken the bull by the horns and learned to manufacturer and process the latest in lens technologies. I

    Adam

  5. #5
    ATO Member OptiBoard Bronze Supporter HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,587
    Blog Entries
    1
    Quote Originally Posted by QDO1
    and
    • The dihedral angle of the frame
    • Frontal angle
    • BVD for the dispensed frame
    • Mono OC's
    • Mono Heights
    In opticianry in the US we refer to the dihedral angle "the angle formed between two planes" as the tilt, is it called the dihedral angle where you practice?

  6. #6
    Master OptiBoarder QDO1's Avatar
    Join Date
    Sep 2005
    Location
    UK
    Occupation
    Dispensing Optician
    Posts
    1,963
    Quote Originally Posted by HarryChiling
    In opticianry in the US we refer to the dihedral angle "the angle formed between two planes" as the tilt, is it called the dihedral angle where you practice?
    no - thats what Rodenstock call it
    Richard King
    Webdesign: http://www.placeofdesign.com
    Photography:
    http://www.kingprophoto.com

  7. #7
    Master OptiBoarder QDO1's Avatar
    Join Date
    Sep 2005
    Location
    UK
    Occupation
    Dispensing Optician
    Posts
    1,963
    Quote Originally Posted by Cherry Optical
    Not to be obtose, but perhaps you should schedule an appointment with your lab rep to talk about the proper ordering procedure and fitting of Free-Form lenses. If he can not help you, I would suggest firing him and calling someone else who has spent time learning about new technology.

    All labs are not equal. Most do a great job of making the same lenses they have been making for the past 100 years. Few have taken the bull by the horns and learned to manufacturer and process the latest in lens technologies. I

    Adam
    I wasnt saying I had any problems measuring and fitting them. Infact I have fitted many. I do have problems with getting the measurements needed from whoeever did the refraction (those measurements specific to the refraction).

    My experience with most other "dispensers" in the industry (note lack of the words qualified or experienced or both) is that they would struggle with the measurements
    Richard King
    Webdesign: http://www.placeofdesign.com
    Photography:
    http://www.kingprophoto.com

  8. #8
    Master OptiBoarder QDO1's Avatar
    Join Date
    Sep 2005
    Location
    UK
    Occupation
    Dispensing Optician
    Posts
    1,963
    Quote Originally Posted by AWTECH
    First all freeform technologies do not need the same information.
    This is an interesting observation. It seems that Free-form is a catch-all type phrase, that describes a certian type of process - It does not however garuntee the quality of the result of the process is comparable between manufacturers or designs

    The word "aspheric" is a similar word. everyone expects "aspheric lenses" to deliver "thinner lenses with superior vision", whereas Aspheric simply means "not spherical" - An aspheric lens could be thinner/thicker and/or with better/poorer optics

    I am always a little wary when a new technology buzz word is touted as the "way to go" or the "latest best thing". I think the quality of a free-form lens is only as high as the quality of the information (measurements etc.) supplied in conjunction with the quality of the algorythm generating the final design
    Richard King
    Webdesign: http://www.placeofdesign.com
    Photography:
    http://www.kingprophoto.com

  9. #9
    Bad address email on file
    Join Date
    Jan 2003
    Location
    Folsom CA USA
    Occupation
    Optometrist
    Posts
    304
    Quote Originally Posted by HarryChiling
    In opticianry in the US we refer to the dihedral angle "the angle formed between two planes" as the tilt, is it called the dihedral angle where you practice?
    Now I'm confused. When you say "tilt" you are NOT referring to pantoscopic tilt, but the angle of "wrap"?????

  10. #10
    Allen Weatherby OptiBoard Gold Supporter
    Join Date
    Jun 2004
    Location
    Florida
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    1,285

    A good lens takes more than Freeform

    Quote Originally Posted by QDO1
    This is an interesting observation. It seems that Free-form is a catch-all type phrase, that describes a certian type of process - It does not however garuntee the quality of the result of the process is comparable between manufacturers or designs

    The word "aspheric" is a similar word. everyone expects "aspheric lenses" to deliver "thinner lenses with superior vision", whereas Aspheric simply means "not spherical" - An aspheric lens could be thinner/thicker and/or with better/poorer optics

    I am always a little wary when a new technology buzz word is touted as the "way to go" or the "latest best thing". I think the quality of a free-form lens is only as high as the quality of the information (measurements etc.) supplied in conjunction with the quality of the algorythm generating the final design
    You have nailed the point I was trying to make. In addition to having any piece of equipment it is necessary to have skilled operators.

    With computers driving the lens manufacturing; freeform machines the operator of the CNC freeform machine, is to a large degree, the lens data generated that software. This software now becomes the operator of the machine. (The actual loading of the lens into the machine to make the lens is even automated in many cases.) "No humans needed here". Where great humans are needed in the process, is in the data entry and the software design and development. The final skilled human needed is the fitting optician. The optician is needed to make sure the fame is properly adjusted and the patient knows how to use the product being fitted.

  11. #11
    sub specie aeternitas Pete Hanlin's Avatar
    Join Date
    May 2000
    Location
    Hickory Creek, TX
    Occupation
    Lens Manufacturer
    Posts
    4,823
    Direct-to-surface (aka, freeform, 360 Digital Surfacing, etc.) processing of lenses is simply a new way to make ophthalmic lenses. True, it is one which expands the potential forms a lens may take, but in the end it still comes down to the design of the lens.

    Darryl Meister has written an excellent article on this topic which may be downloaded from this website.

    The additional measurements required by some lenses inform the additional parameters possible with direct-to-surface lenses. In a way, by providing extra parameters regarding the fit (or the wearer him/herself), you are providing a more precisely tailored finished product to your patient. However, other lenses may benefit from the advantages of the direct-to-surface process without additional measurements.

    Some manufacturers, like Rodenstock and Zeiss, have elected to compensate for the "as-worn" position of the lenses. Therefore, they ask for the panto, wrap, and vertex measurements. Some lenses are personalized to visual habits of the wearer (e.g., Varilux Ipseo, which incorporates measurements taken with the Vision Print System). Some lenses are informed by lifestyle questions- such as the Seiko Super Proceed 1 Internal.

    There will doubtless be many many designs that arise from direct-to-surface technology. Choosing the ones you dispense will require an understanding of a.) what the technology is really offering by way of advancement, and b.) what is required to properly fit the lenses.

    Varilux Physio, which Essilor just launched, benefits from direct-to-surface technology on the front (design) side of the lens. Using direct surfaced molds (Essilor's name for the process is "360 Digital Surfacing"), the wavefront is controled as it passes through the lens to the eye- eliminating higher order aberrations commonly found in PAL lenses. However, no additional measurements are required- the design "gain" is in the optimization of the front design (and greater accuracy of the molds). Varilux Physio 360 is also digitally surfaced on the back side- to preserve the progressive design against the distortion caused by the patient's distance Rx (which is commonly surfaced on the back of the lens).
    Last edited by Pete Hanlin; 06-21-2007 at 09:05 AM.

  12. #12
    Allen Weatherby OptiBoard Gold Supporter
    Join Date
    Jun 2004
    Location
    Florida
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    1,285

    Physio & 360 Explaned? Plus a few questions

    Thanks Pete for the information about the Physio and the 360.

    I can now understand the marketing of the Physio. What your company is claiming is that the mold quality is digitally controlled. This is the same basic approach to making a freeform lens on the fly.

    The fact is digitally controlled molds for progressives is not new technology. Many progressive designs are made with digetally controlled mold equipment. The main difference in the equipment is the time needed to cut a progressive metal mold is hours not minutes.

    It is back to the design of the lens that is important. For example I would like to know how many different combinations of prescriptions are available for the Physio and how many for the 360.

    In general there are about 1/2 million combinations of Rx's I would guess for the the front cast lens and for the 360 back freeform I would guess their are almost 1 million or possibly more.

    These numbers are just a guess since I have not seen how many blanks are offered nor do I have the rx ranges available.

  13. #13
    ATO Member OptiBoard Bronze Supporter HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,587
    Blog Entries
    1
    Quote Originally Posted by William Stacy O.D.
    Now I'm confused. When you say "tilt" you are NOT referring to pantoscopic tilt, but the angle of "wrap"?????
    Actually both would be considered a dihedral angle, the plane that would be the major reference would be the plane that the patient is refracted on in the phoropter. Any change to this plane is going to induce cylinder and change power as well as the axis. Panto, retro, face form, wrap, these are all changes to the plane the Rx lens sits on and the angle of change is called the dihedral angle. You can check the effects of tilt to lenses with Darryls Rx Compensator, or even dowload my equation calculators from the files directory.

    As for the benifits of a lens with free form front surface that can be generated on the back with conventional machines. It does offer additional benifits, take for example a 6 base lens with a 3 add. The umbilic on this lens would be very narrow, however with the technology to control the lens parameters on a point by point basis across the lens surface you have the opportunity to widen or increase the umbilic and offering more visual real estate if you will, and since a 6 base is going to fit a range of Rx's from +2 to -2 it does give you a ball park as to what the Rx in this lens is going to be so that you can make front surface changes to help control abberations such as marginal astigmatism.

    The difference between the Physio and 360 is that the physio is going to assume that you are going to use the power within the base curves parameters and is optimized for the abberations using this ball park figure on the front surface, where the 360 design would allow the ball park figure to be optimized even further on the back surface with additional curve changes. This would allow essilor to customize an Rx without having to make a million different molds.
    Last edited by HarryChiling; 01-16-2006 at 11:31 PM.

  14. #14
    Master OptiBoarder QDO1's Avatar
    Join Date
    Sep 2005
    Location
    UK
    Occupation
    Dispensing Optician
    Posts
    1,963
    the dihedral thing throws up a interesting point

    Dihedral - wrap - faceform ... are all considered by different professionals to mean the same thing (it just depends if you are in Germany, the UK, or USA) problem is, the Germans sent the orderpads + literature with the word "dihedral" on to the UK. It confused us for a while untill we sussed out what they really wanted
    Richard King
    Webdesign: http://www.placeofdesign.com
    Photography:
    http://www.kingprophoto.com

  15. #15
    Bad address email on file
    Join Date
    Jan 2003
    Location
    Folsom CA USA
    Occupation
    Optometrist
    Posts
    304
    Quote Originally Posted by QDO1
    the dihedral thing throws up a interesting point

    Dihedral - wrap - faceform ... are all considered by different professionals to mean the same thing (it just depends if you are in Germany, the UK, or USA) problem is, the Germans sent the orderpads + literature with the word "dihedral" on to the UK. It confused us for a while untill we sussed out what they really wanted
    I got confused because:

    Originally Posted by HarryChiling
    In opticianry in the US we refer to the dihedral angle "the angle formed between two planes" as the tilt, is it called the dihedral angle where you practice?

    and I thought he meant pantoscopic "tilt", but his last post was completely ambiguous on what dihedral meant in ophthalmic optics. If I understand you, it refers to the angle between two lenses, commonly known as "wrap", rather than panto. Or am I still confused?

  16. #16
    Master OptiBoarder QDO1's Avatar
    Join Date
    Sep 2005
    Location
    UK
    Occupation
    Dispensing Optician
    Posts
    1,963
    Quote Originally Posted by William Stacy O.D.
    I got confused because:

    Originally Posted by HarryChiling
    In opticianry in the US we refer to the dihedral angle "the angle formed between two planes" as the tilt, is it called the dihedral angle where you practice?

    and I thought he meant pantoscopic "tilt", but his last post was completely ambiguous on what dihedral meant in ophthalmic optics. If I understand you, it refers to the angle between two lenses, commonly known as "wrap", rather than panto. Or am I still confused?
    i aggree with you, i never heard dihedral to mean panto in ophthalmic optics, but in mathematics,when considering 2 planes, harry is right.

    I was assuming you guys allready were dispensing ILT's. trust me - when you first see an order form you will firstly go "what the XXX" followed by "that will take ages to fill out", followed by "what on earth do they mean by that?"

    The results of the pudding are in the eating, and the results that come back - in terms of VA, returns, acceptance and patient feedback are very very good

    I calculate a pretty close value for what I am expecting the lens to be (once adjusted for position of wear) before ordering the lenses. This has 2 advantages... I know "just about" what the manufacturer is going to do next, which makes checking a lot easier. (I expect the manufacturer issued RX to be pretty close to my calculated one), and secondly, if a manufacturer does not offer that service for a particular lens, but I want it, I can order the adjusted RX myself
    Richard King
    Webdesign: http://www.placeofdesign.com
    Photography:
    http://www.kingprophoto.com

  17. #17
    ATO Member OptiBoard Bronze Supporter HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,587
    Blog Entries
    1
    Here is a better explanation of a dihedral angle

    http://mathworld.wolfram.com/DihedralAngle.html

    Quote Originally Posted by William Stacy O.D.
    but his last post was completely ambiguous on what dihedral meant in ophthalmic optics
    That is because I have never heard a tilt (any direction) refered to as a dihedral angle. I don't explain things very well, but a dihedral angle is taught in the most basic geometry class, I did not think I had to explain this in detail. I was just curious if that was what tilts were called over in the UK. Thanks for the explanation QDO1.

  18. #18
    OptiBoard Professional
    Join Date
    Apr 2005
    Location
    San Diego
    Occupation
    Dispensing Optician
    Posts
    230
    could someone explain in a little more depth the difference between direct surface molding and the conventional methods of progressive surfacing. Pete, if you read this, could you explain more about the digital surfacing technique your company employs, or Awtech could you as well?

  19. #19
    Allen Weatherby OptiBoard Gold Supporter
    Join Date
    Jun 2004
    Location
    Florida
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    1,285

    Digital Surfacing

    Rolandclaur asks:
    could someone explain in a little more depth the difference between direct surface molding and the conventional methods of progressive surfacing.
    I am not sure if you are asking about how a progressive mold is made or if you are asking how a traditional progessive is surfaced.

    First lets start with a traditional progressive. These are made by casting, (or injecting for poly), the lens material into a mold with the front surface of the lens formed to the reverse image of the progressive lens. This surface has a fixed non-spherical design for both the far and the near vision. This is how the semi-finished blank is produced. Then a lab takes the correct semi-finished blank, (there are between 65 to 90 different blanks needed for the range of all progressives), and then the lab cuts the matching spherical curve to give the desired powers for Far and Near vision from the selected blank semi-finished lens.

    The Freeform lens starts with either a semi-finished non-spherical front curve, which in the case of Definity has a part of the add power cast into the front of the lens or in some cases a spherical front curve can be used and either the backside only can be freeform cut or both sides can be freeform cut.

    What freeform cutting involves is the ability to cut any surface you want. For example: you could take a semi-finished blank and make an oval that is 2mm inset into the lens with an a deminsion of 30mm and B dimension of 10mm. This would not produce a lens you can see out of but my point is any shape you can dream up you can cut. I saw a demonstration of the Playboy logo cut into a lens using a freeform machine.

    To make a lens that works for freeform you need the lens design capability to go with the machine.

    If this does not answer your question please try to be specific as to what exactly you want to know.

  20. #20
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    5,146

    Redhot Jumper I think we all get *lost* in the discussion of free-form...

    and forget that (currently) refraction technology and methodology lags WAY behind design and fabrication technology. I don't think we need even more precise technology in eyewear or lenses or measurements...
    We need FAR better methods to deteremine the optimal refractive state (and use) for that patient.

    Vision is fluid. Very precise technology(free form) is, in my opinion, not where we should be putting our efforts for better vision. A device that would be analogous to an "visual breathlizer" that would be adminstered at trafic accidents and police events would go a long way to getting the public to appreciate and demand better vision (products and methodology). But as long as local DMVs test acuity at such bare minimum thresholds and frequency (20/40 tested at 6 feet!!! and only once every *8* years!! in NY), there really is no need for the public to be really interested in better vision.

    My 2 cents
    Barry

  21. #21
    Allen Weatherby OptiBoard Gold Supporter
    Join Date
    Jun 2004
    Location
    Florida
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    1,285

    Freeform lens designs and Refraction

    Barry;

    People are interested in better vision for more than passing a driving test. Yes refraction is next area that could use improvement. I saw a new piece of equipment that can do the refraction, a wavefront measurement as well as all other functions needed to check persons eyesight. This technology is not yet on the market, but will go a long way to producing better prescription numbers. It is a truely all in one machine.

    I think in the future using a combination of new refraction technology and freeform even better vision may be attaineded.

    Remember freeform is not a lens design. A lens design using freeform such as the Seiko Succeed in very good progressive design with approximately 30% more visual area and it also eleminates all of the swim and sway associated with traditional progressives. This and a few other lenses will fit into a new catagory Super Premium Progressives. Yes they cost a little more but the patient actual can have substantially better vision.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. free form lenses
    By redsoxfanfewany in forum General Optics and Eyecare Discussion Forum
    Replies: 22
    Last Post: 06-03-2008, 01:42 AM
  2. Free Form Generating
    By skirk1975 in forum General Optics and Eyecare Discussion Forum
    Replies: 17
    Last Post: 11-15-2006, 12:18 PM
  3. Free Form Materials
    By skirk1975 in forum General Optics and Eyecare Discussion Forum
    Replies: 8
    Last Post: 01-18-2006, 12:23 AM
  4. Free Form Front and Back Grinding ?'s
    By skirk1975 in forum General Optics and Eyecare Discussion Forum
    Replies: 3
    Last Post: 06-16-2005, 11:47 PM
  5. Free Form & Independent Labs
    By johntricity in forum General Optics and Eyecare Discussion Forum
    Replies: 6
    Last Post: 11-22-2003, 09:41 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
  •  
OptiBoard is proudly sponsored by:
FEA Industries, Younger Optics, Carl Zeiss Vision, Vision Systems, Inc. and Chemistrie Eyewear