Freeform Lenses

[CCrawford]

Are freeform lenses (even the budget type) better to adapt to/provide better vision than good "conventional" lenses like essilor comfort, hoya wide etc?

The reason I ask, is that some of the freeform lenses are a lot cheaper than comfort and hoya wide. A colleague said freeform is always better, even budget ones. But I always thought what u pay for is what u get!

(the budget freeform lens that I was thinking of using is the jaikudo wideview)

This is a link to totallyoptical.com's section on Free Form technology. It's worth the read!

http://www.totallyoptical.com/ME2/di...F0D5CAA5564D79

[Mr.Powers]

We are selling Precision from swisscoat whit great succes, im pretty sure its rodenstock impression design since www.swisscoat.com also sells rodenstock and the fixd are the same 15-17-19 and 21 in the sport design.

http://www2.swisscoat.com/index.php?...=521&Itemid=28

but is seams like there Supreme coat is not as easy to clean as essilors forte.

but the progression is great so buttom line freeform great in cheap lenses but maybe its on the coating they spare the money.

best regards

Peter

[OCP]

We are selling Precision from swisscoat whit great succes, im pretty sure its rodenstock impression design since www.swisscoat.com also sells rodenstock and the fixd are the same 15-17-19 and 21 in the sport design.

http://www2.swisscoat.com/index.php?...=521&Itemid=28

but is seams like there Supreme coat is not as easy to clean as essilors forte.

but the progression is great so buttom line freeform great in cheap lenses but maybe its on the coating they spare the money.

best regards

Peter

As far as I know it is Seiko FF Succeed design

Mike

[David_Garza]

it rather stands for a range/family of lenses, more details are available from Alan Yuster at ProFit Optix in Florida.

Georg Mayer
Rodenstock Munich

Now they are in Texas area: http://www.profitoptix.com/aboutus.html

[specs2see]

Understanding Digital Lenses Does anyone have trouble understanding all the new terms used to describe progressive lenses? I am referring to terms like; free-form, direct-to-surface, high definition, digitally computed, digital processing, digitally enhanced, and so on. I will try to blow away the clouds of confusion to give you a better understanding of what going digital is all about. When you read about a lens that is made by some kind of digital processing, don't assume that the lens is somehow better. It may or may not be. Digital suggests a higher level of precision. I would argue that all lenses created since the late eighties have been made using some form of digital processing. I think it is important not to get caught up in the digital hype. Digital lenses are often generically called free-form lenses. The term free-form is often misunderstood. Many optical professionals think of free-form as the lenses they receive from the laboratory. They think that the lenses are superior because digital production has been used. A twenty five year old progressive design lens can be made using digital or free-form equipment. Does that make that older design lens better? Confused? Yes? So are a lot of other ECPs! I want you to think of free-form as a manufacturing process, not as a lens. Think of free-form as direct surfacing. What that really means is that this technology allows lens designers great freedom for lens designs because they are not confined to using the traditional semi-finished lens blanks. The optical design of these new lenses can be customized and optimized to the fitting and prescription requirements of the patient. Direct surfacing allows the manufacturer to produce a lens that you can grind the front or back surface of to produce a highly accurate and customized finished product. The remainder of my discussion of lenses will be geared towards progressive lenses. Traditional lens manufacturing involved using a semi-finished lens blank that was molded using glass molds. The progressive design, base curve, and add power were molded on the front surface of the lens using these molds. The laboratory would then grind the patient's prescription into the back surface of the blank using a generator. The lens would then go to surface finers and polishers to complete the grinding process. This process did not allow for any customization of the progressive designs. Traditional surfacing has many limitations. Free-form manufacturing can produce a highly customized and highly accurate finished lens. The starting point for free-form manufacturing starts with the highly sophisticated software. This software allows the input of prescription, frame fitting details, and position of wear to create a truly customized lens that is not possible with traditional lenses. This software sends data to the free-form generators in the form of point files. These point files are mathematical data files that guide the free-form generator. Lens manufacturers sell these point files to the laboratories. The point files are usually sold in batches, which allow the laboratories to produce the branded progressive lens of the manufacturer. The point files can only be used once since each is customized to the patients individual prescription needs. The generating creates the prescription, add power, base curve, and corridor position of the finished lens. The generator uses a single point cutter to produce the lenses. This cutting can be done on both the front and back of a lens. Most free-form generators will have a second or even a third cutter that produces a very smooth surface. The lens is then finished on a specialized lens polisher that uses conformable tools. These conformable tools, or soft laps, have been developed to buff the surface of the lens without destroying the sophisticated lens surface. The polishing of these lenses has been a weak point in the free-form production chain. Equipment manufacturers have made big strides in this area. Again, think of free-form as a manufacturing process involving the design and fabrication of lenses, not the actual lens itself. Let's take another look at the word digital. The word digital means processing, operating on, storing, transmitting, representing, or displaying data in the form of numeric digits. There is no mention of optical lenses in that definition! We now know that lenses have been made using digital equipment for a long time. We also know that free-form is a process, not a lens. Let us examine the different ways a progressive lens can be fabricated using digital surfacing, or free-form processing. Progressive lenses can be made with: 1. Traditional front molded designs that have been made using molds that have been digitally manufactured. 2. Traditional front molded design with digital backside surfacing. 3. Front side spherical curves with the progressive design on the back of the lens. 4. Progressive front surface with atoric/aspheric back surface. 5. Add power distributed on the front and back surface The word digital can be used to describe the way the mold was made, the way the lens was designed, the process used to generate the curves, and any number of real or imaginary ways. Remember that just because a lens is made using digital surfacing, or it was digitally surfaced, or was made using free-form technology, that it does not automatically mean that the lens is somehow better. I think that the world of free-form manufacturing has great potential. The accuracy and customization capabilities are amazing. The finished product is only as good as the manufacturing process. The process cannot improve a poorly designed lens. It is our job to study the available technology and make an informed decision. There are some very good lens designs that maximize the benefits of digital surfacing. Contact the lens manufacturers and your laboratories to discuss free-form technology. Educate yourself so you can educate your patients. Your patients deserve the best. Give it to them!

I thought this may be helpful. it was in one of the trade magazines

[fvc2020savage]

..

[Roscoe]

I'm not sure how many folks out there will benefit from this, but I recently came up with the following information for staff training purposes...and to assist in patient education. It was my attempt to address the confusion surrounding freeform and digital lenses. I titled it "Understanding Digital and Freeform Lens Technology" and it's available in PDF form (with more details and brand-specific examples) if you're interested. Enjoy! -Roger Smith

Q: What is a "digital" lens, and what makes it so special?
A:The term "digital" refers to a newer and advanced PROCESS of surfacing a lens. A digital generator uses a computer-guided lathe that cuts and polishes the lens in one step utilizing a diamond point. This process yields a lens that is more accurate and made in less time than was previously possible with traditional lens manufacturing (which uses molds, a rougher cutting instrument, and a series of sanding/polishing stages).

Q: What is a "freeform" lens, and what makes it so special
A: In short, a freeform lens is "unique, ONE-OF-A-KIND, and notcookie-cutter". However, what makes it ONE-OF-A-KIND involves the 1) PROCESS and 2) DESIGN compensations.
- PROCESS: Every SV and PAL freeform lens utilizes the digital lathe process for part or all of the lens
- DESIGN compensations: This relates to computer software which provides instructions to the digital lathe generator. The software will create customized instructions for all SV and PAL freeform lenses based on lens shape and size (frame info). However, there are more sophisticated freeform designs which will incorporate optimized prescription information (i.e. Zeiss iScription), and the most sophisticated freeform designs will generate a compensated prescription & lenses based on all of the above PLUS the patient's "position of wear" measurements (panto, wrap, vertex).

Q: So, in a nutshell, what's the difference between "digital"and "freeform"?
A: "Digital" refers to the precise, computer-driven, diamond point lathe. It precisely and accurately follows the computer's instructions. "Freeform" refers to the computer program that compensates the lens Rx and design before it gives those instructions to the digital generator/lathe.

[sharpstick777]

Lets go back to the basics of what Free-form "frees" for a moment and Digital solves. Two of the key problems with ground lenses (any ground lens) are base curve and tool problems.

DIGITAL: On manufacturing, the average tool discrepency from true is .07 D, which means that even if I have the correct tool/lap the job starts off .07 D on average. A fully stocked lab has over 4000 tools, and if I have 1000 jobs in process it means half my tools/laps are missing at any give time. So I take my tray to the tool room, and my lab ticket gives me the best tool, the second and third best tools for that job. So I might be able to substitue a 1.67 tool for my CR-39 lens in a different power, but its not perfect. We start substituting tools for a lot of jobs. Of course I can make a tool, but that means I have to take a job off a generator to make a tool, slowing everything down (there is no money in tools). Or it could wait, and wait. And that post-it I left in the empty tool slot gets thrown away on Friday at 4pm. So that means in most cases we substitute, and most cases that tool is off even if we don't.

A free-form generator has only one tool/blade, its always there. It self calibrates daily and it tells me when the tool/blade is about to wear to the point its no longer good.

FREE-FORM: With ground lenses we have to make compromises. In a progressive, if I stocked every material, every add power, every Transistions or Polarized option, gray and brown and every base curve, I would need over 24,000 blanks. Just for one brand and model. We cant afford that so we start cutting corners, and the first thing we start cutting is reducing base curves from 45 to 5-6. Do you know from among those what factor has the greatest effect on DVA? Base curve. So when we stock only 5 or 6 base curves we only give 5 or 6 RXs perfect optics, everything else is a compromise. The first thing free-form lenses did was modify curves to give every lens the possibility of true/best form optics. Oblique Marginal Astigmatism is also a base curve issue really, affecting cylinder and astigmatism the same way. Only with Free-form optics can we solve base curve issues and give the patient a customized atoric back-side curve.

So with Digitial Processing and Free-form optics we in one fell swoop solve the 2 most eggregarious problems caused by ground lenses and traditional cast blanks.

If we don't discuss the problems of ground progressive lenses, we can't fully begin to understand the advantages of Digital manufacturing and Free-form Optics.

[rdcoach5]

I wore the Unique and loved it for distance as will everyone, Intermediate and near are lacking compared to GT23D ,Definity or Visionary Max by Toledo Optical.