CONTINUING EDUCATION, 1 CE Credit  $9.99, 1 Hour, General Knowledge, Level 1, Release date: October 2007, Expiration date: October 31, 2012

merchant processing services

Merchant Processing Services

 
 
 
 
 
 
 
 
 
 
 
THROUGH THE LENS

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!

Bob Fesmire, ABOC

Comments
Sign in or register to begin posting comments!
User Name:
Password:
optigrrl
Posted: 2/24/2009 8:58:52 AM

That was an excellent article and perfect summerization on the terms and processes for digital and free-form manufacturing. I will print this and use it in presenting lens technology!
osilio
Posted: 7/12/2010 9:55:09 AM

Mr. Fesmire..very good resume and article! you have here in few and clear words a very good explanation to understand something that we will be talking from here to the future..Digital Surfacing in lens technology.
pathimain
Posted: 9/25/2010 4:36:37 AM

DEAR SIR, I,M OPTICAL LENSE SURFACING LAB OWNER IN SRI LANKA.I,M REPRESENTING A THIRD WORLD COUNTRY SO I LIKE TO KNOW MORE DETAILS ABOUT LENSE SURFAING NEW TECNOLOGY. SO WOULD YOU PLEASE SEND ME THE NEW METHODS FOR ME. BEST REGARDS, ANTON DE SILVA
REZA
Posted: 9/25/2010 2:52:48 PM

Dear Bob i am an optometrist and optician who has worked in very big traditional lab in europe and recently wantsto run my own lab free form machines.could you help me in two issuses about free form technology: 1 .could you introduce me the best first fifth free form less brand name in the world according to thier machines quality and easy to work and matenace. 2 .you mentioned that we have to buy points files to made a spacial type of lens .to make it cleaer ,for example ; if we want to make a progressive life xs ,we have to pay to rodenstock company to get permition for production or to get an spacial software for our generator to make this lens. i do appriciation in advance for your good articel Best Regards REZA




Editted: 9/25/2010 2:53:42 PM by REZA

inneso@yahoo.co.uk
Posted: 7/8/2011 7:35:57 AM

l also own a surfacing lab. , while l order free form lenses from Europe , how can l see the difference between the free form lenses and the conventional lenses
davisd
Posted: 10/21/2011 8:59:39 AM

This explanation was explicit. Thank you for giving me understanding.
Steve Kroll
Posted: 3/3/2012 7:46:34 AM

Great article, Very informative, In thirty four years I have learned when presenting to patients keep it simple and use buzz words. Don't let them try to analyze what You tell them.
jay
Posted: 12/30/2012 10:10:31 AM

very informative pls do elaborate more for opticians
angel
Posted: 1/28/2013 5:11:47 AM

Those who enjoy having different types of sunglasses have reason to smile as this article is going to provide the relevant information and also will let them know how they will be able to get varieties of such glasses. The article will actually provide you several choices by offering useful information regarding the eyewear wholesale and enables you to get some latest collections of eyewear. Sunglasses are quite in vogue nowadays and people love to wear, and have different sunglasses in their wardrobes. If you enjoy having collection of different types of Eyewear Wholesale then you are at the right place to gather some important ideas and eventually will be able to add some more items to the existing list. Apparently, the sunglasses have become an integral part of the fashion and used by people to a large extent. If you are seeking to invest your hard earned money on designer brands, then you are probably the right one to get the useful advise, and need to think twice before doing so. Spending hefty amount of money on purchasing a single item is certainly not a wise decision, after all why should you invest your hard earned money on purchasing a highly expensive branded item. Undoubtedly, you will be able to find cheap sunglasses everywhere nowadays and will also be able to save your money. Apparently, the cheap sunglasses will cater your desires of becoming a good looking person as these are beautifully designed to make replica versions of some branded sunglasses. So, you will certainly be able to get the same exposure while wearing such sunglasses and can make a great impression on the people around you. Even though replicas are offered at cheap prices, still it claims having positive feedbacks from number of people. Of course, these sunglasses are manufactured by using the best quality of materials and designed with perfect detail to enhance your beauty and personality. You can easily differentiate the replica and original sunglasses as such sunglasses are designed smartly to make it eye catchy, to tantalize the sense of number of people. The above facts make it quite obvious that brand has nothing to do with the style, so you must set your eyes on cheaper sunglasses rather than purchasing the expensive one. Undeniably, the replica sunglasses are fully capable of making you more glamorous and help you in saving your hard earned money.
kjin
Posted: 5/18/2013 4:55:43 PM

Thank you for nice article, we are dealing with digital lenses recently, and could see there are quite a big difference between patient's Rx and lab final power level. May I have an answer for this issue? Thank you.
Currently Viewing 10 of 10 Comments      
APRIL ISSUE FEATURES

Spring and Summer Suns
Leave the winter behind and brighten up your practice with the latest in colorful sunwear...

Selling Sunwear
Increase your sunglass sales by staying on top 
of the latest in shapes and styles
...

Buying Groups
Some tips of how to evaluate if a buying group 
or business alliance is right for your practice
...
Purchasing Patterns 
Use lens invoice sales data to spot trends that could help determine potential areas of growth...
Optical Apps
See the latest in fitting, dispensing, education, and lens design apps for smartphones and tablets...
Stereotypes
Every ECP has at one time or another made an assumption as to how much a patient can afford...
All About Edgers
Edgers with drilling capabilities gives your practice a clear advantage over your competitors...
Contact Lens Graffiti
ECPs face challenges dealing with the various films and deposits commonly found on contact lenses...
Foam Party Danger
Trendy foam parties can lead to a number of ocular injuries and other potential dangers...
Homebound Eye Care
Nursing Home and Homebound eye care is a challenging but ultimately rewarding service...
Optician Patient Relationship
Make an emotional connection to nurture the optician patient relationship...
Snow...Snow...Snow
Endless snow, like we experienced this winter, can lead to some interesting customer experiences...
Eye Care Industry Movers and Shakers
This month's professionals who are shaking
up the eye care industry...
LIKE US ON FACEBOOK

Send press releases to: editor@ecpmag.com
 
 
 
All content is the property of ECPMag.com OptiCourier Ltd. &  assoc. vendors. Website Powered and Developed by EyeVertise.com - 847.202.1411 | email