Tuesday, August 29, 2006

Short-Corridor Progressive Lenses

This one is for the baby boomers.
If you wear eyeglasses, then I am sure that you have noticed by now that frame styles are getting smaller and smaller compared to the eighties when it seemed frame manufacturers were trying to see how big they could make them.
Well how does that affect us bifocal wearers, especially those who wear
Progressives lenses?

I thought the best way to teach my readers on this subject would be to post an actual article that is used for Continued Education for Professional Licensed Opticians.
I read this , then had to take a test on it to get a Continued Education Credit, which is reqired in order for us Licensed opticians to stay Certified.
It is kind of long, but full of great info, I think you will be able to learn a lot about lenses, and about how you should be treated from your optician when deciding on your eyewear options.

It was written by: Judy M. Canty, ABOC

If you've heard it once, you've heard it a thousand times. Ours is a culture that places a high value on youth or at least the appearance of youth. It's reflected in the way we dress, the music we listen to, the cars we drive. We wear eyeglasses as much to make a statement about our attitude as we do to actually see comfortably.

Short-corridor progressive lenses can provide solutions to any number of eyewear design issues. But, as with any other lens category, the more you know about it, the better prepared you will be to advise your customers.

In the beginning, there were progressive lenses. They were designed to provide seamless vision from distance, through intermediate to reading areas. The early designs were somewhat less than satisfactory. Uncomfortable amounts of unwanted astigmatism at the lens peripheries coupled with relatively narrow transitional corridors and reading areas limited their acceptance to only the most dedicated and motivated of wearers. However, as lens design technologies became more sophisticated, progressive addition lenses became increasingly "user-friendly." Eyecare professionals now had lens designs they could recommend and use with greater confidence. Combine these more sophisticated lens designs with the coming of age of the Baby Boomer generation, add a healthy dash of fashion savvy and the market for progressive addition lenses exploded. Then, in the early 1990s frame sizes began to shrink and those wonderfully designed progressive addition lenses couldn't function as they were designed to. The transitional corridors were too long and the reading areas were lost in the edging process. So, we began to "bump" addition powers, essentially forcing wearers to read in the transitional corridor rather than in the near power area. The corridor is too narrow to allow a comfortable reading area, so customers once again complained about the difficulty in using progressive addition lenses.


In 1999, the first short-corridor progressive lens was introduced to the marketplace. It was designed for the new, smaller frame styles, with a shortened corridor allowing the near vision and reading areas to remain largely intact. Rather than the average 17mm corridor length requiring a 20 to 25mm fitting height, it sported a 13 to 15mm corridor depending on the reading power, and allowing for a minimum fitting height of 17 to 19mm. Eyecare professionals were back on track again with the first real solution for their fashion conscious presbyopes. Almost immediately, lens manufacturers began lowering the minimum fitting heights for their current progressive lenses. The justification for this decision was that, in many cases roughly 85 percent of the addition power was reached at this point on the lens. 85 percent sounds good until you realize that a +2.00 add power was now an unacceptable +1.70. At best, it was a stopgap measure allowing their lens designers time to create the next generation of progressive addition lenses.


In less than three years, a number of lens manufacturers have released short-corridor progressive lenses in a variety of materials. Conventional plastic materials have long been the lens material of choice, however newer mid- and high-index materials as well as polycarbonate, are rapidly gaining in popularity, as are additional lens treatments such as variable tints and anti-reflective coatings. A small number of short-corridor progressive lenses are also available in crown glass. Most lens manufacturers provide laser-etchings on the surface of their lenses to help the optician properly identify manufacturer, lens design, material, addition power and location of the optimal reading area. The wise eyecare professional will keep abreast of these new designs since many of the major manufacturers are advertising them directly to the consumer. Your customer will need your expert assistance in sorting through all the choices and selecting the best lens for their needs.


Short-corridor progressive lenses are designed to meet a specific combination of needs. However you choose to determine your customers needs and wants, with a "lifestyle questionnaire" or through general conversation, matching customer to lens style is critical to their success as a wearer. "How do you use your lenses?" may sound like a dumb question, but it really isn't. Yes, they use them to see, but how? Both fashion and function motivate the best possible candidate. They have taken great pains to remain fashion-forward and are conscious of the image they project. They have come to the realization that they need help with reading and close work, and are ready for their eyecare professional's help. Co-workers, friends or family may influence them, especially their kids, with their frame selections and now need your help in combining all those needs and wants into fashionable and functional eyewear. Short-corridor progressive lenses are also an excellent solution for those customers whose facial structure requires a small frame.

TALKING TO YOUR CUSTOMERS ABOUT SHORT-CORRIDOR PROGRESSIVES

This new lens category means that as an eyecare professional, we need to re-think how we present the idea of progressive lenses. A single generic description of the advantages of progressive lenses is no longer a good idea. Begin by reading the technical literature provided by the manufacturers. Double check that information with other sources such as independently published lens data. Familiarize yourself with the kinds of consumer advertising that your customer will see so that you can answer questions that they might have. Ask your customer about what they need their lenses to do and then be quiet and listen. Ask them about previous experiences with multifocal lenses and progressive lenses in particular, then be quiet and listen. They expect you to be able to piece all of this information together and come up with a solution. Repeat their concerns and expectations back to them to verify that you have the correct information and begin to describe how particular designs will help. But, above all, don't over-promise on lens performance. Let your customer know how this new lens design is different from what they might have used in the past so that they won't be surprised and possibly unhappy with their purchase. Short-corridor lenses are just one of many options available in progressive lens designs and one lens may not cover all the needs your customer will have.


PROPER FITTING PROCEDURES FOR SHORT-CORRIDOR PROGRESSIVES

As with any progressive lens, fitting a short-corridor lens requires some groundwork.
Monocular PDs are imperative, preferably taken with a pupilometer for accuracy. Make sure your patient is holding the end of the pupilometer firmly against the face much like looking through a pair of binoculars. Record this measurement in monocular or "split" PD form, i.e. 32/31.

Select the proper size frame for measurements. It may not be the correct color, but size is indeed what matters in this instance.

Adjust the frame fit, if necessary, so that the nose pads, pantoscopic tilt and temple bend are comfortable. If possible allow the customer to wear the frame for a few minutes to become comfortable with the fit and so that you can note head position when sitting and standing. Remember, where you think the frame should fit and where your customer actually wears it may not agree. They need to be comfortable at all costs. If you have had to change the pantoscopic tilt of the frame, note it in the patient's record so that you can duplicate it if you are not using the fitted frame.

Make sure that your chair height allows you to work at the same eye level as your customer. If you are looking up or down while taking your measurements, they will not be as accurate as they should be.

Using a felt tip pen or fine point marker, dot the center of the pupil on the demo lens in the frame. If no demo lens is available, try covering that portion of the frame with transparent tape to provide a marking surface. The truly steady-handed optician will be able to use a PD ruler to measure pupil height, but marking the demo lens is still the better option
Using a PD ruler, measure the distance from the pupil mark to the deepest point on the frame eyewire, not at the point directly below the pupil mark. This measurement is the seg height you will order from the lab.

Using cut-out charts provided by the lens manufacturer, verify that the lenses will work with the chosen frame. If the frame you and your customer selected will not work even with the short-corridor design, don't try to make it work. Choose another frame and repeat the process. Your customer will appreciate your attention to detail and your interest in his or her success with short-corridor progressive lenses

ORDERING SHORT-CORRIDOR PROGRESSIVE LENSES

There is no big secret to ordering short-corridor progressive lenses. As with any lab order make sure that your lab can provide the lens design that you need. Check your order form for accuracy and legibility. Don't make the lab guess at numbers and signs. If possible send the frame to the lab for processing. If you prefer to do your own edging, remember that old carpenter's rule, "measure twice, cut once." These lenses are too expensive to have to remake for an error in measurements.

Before dispensing, verify the power, optical center placement and seg height for accuracy. If necessary, adjust the pantoscopic tilt and bring the frame into standard four-point alignment. Some opticians prefer to leave any markings intact on the lenses to aid in the final adjustment; others prefer a pristine lens surface to present to the customer. Either choice is acceptable.

DISPENSING SHORT-CORRIDOR PROGRESSIVE LENSES

Begin the process by reviewing the lens properties that were decided on when the order was placed.

Have reading material of various sizes at hand to help your customer begin the learning process. Many opticians find it beneficial to begin with slightly larger than average print size and introduce different and smaller sizes so that the customer understands the transitional corridor and how it leads the eyes to the reading area.

Let the customer know that these lenses may require slightly more head movement than usual, at least during the initial learning period but with time that should decrease. Be sure he or she understands that it will take several days for the visual system to become accustomed to a new set of lenses and that the greater the wearing time the faster the learning process becomes. Caution the customer that switching back and forth between the new glasses and the previous pair will only slow down or even stop the entire process.

Have the customer move from distance viewing to intermediate to reading rather slowly to reinforce the idea of progressively increasing lens power.

Once the customer is comfortable at the dispensing table, it's time to get up and move around a bit to understand how to use the lenses while standing and walking. Emphasize that to comfortably navigate stairs and curbs, it will be necessary to tilt the head down and look through the distance portion of the lens to have the sharpest vision.

Finally, instruct your customer on the care and maintenance of this new purchase. Suggest the proper cleaning solutions and the way they should be used. Remind them that using two hands to put glasses on and take them off will preserve their adjustment and that storing them in their case will prevent accidental damage.

Savvy opticians will make a follow-up appointment to check the adjustment of the frame, ensuring that the customer is completely satisfied with their selections.

TROUBLESHOOTING SHORT-CORRIDOR PROGRESSIVE LENSES

Okay, so you've done everything by the numbers. The frame fits properly. The lenses were fabricated properly and your customer is still having problems. The first thing to do is NOT remake the lenses, changing a base curve or the seg height or the PDs. The first thing to do is listen to what your customer is saying. Did the environment in which they are using the lenses change? Are they spending more time at the computer than they originally thought? Has the frame adjustment been altered? Do flat surfaces appear curved? Or did someone close to them whose opinion they value react negatively to the frame? The key here is to listen, repeat what you heard to make sure you understand and then make your decisions. Ask your questions based on what they said, not what you were thinking.

Changing the pantoscopic tilt may solve flat surfaces that appear to curve


Difficulty in using the transitional corridor or insufficient reading area may be solved by changing the frame's vertex distance or changing the "face form" of the frame. Keep in mind that changing the "face form" will impact the optical center placement.Holding the head in an uncomfortable position may mean that the segs are either too high or too low. Re-mark the lenses and check their placement relative to the eyes. You may be able to solve this problem by raising or lowering the frame with a nosepad adjustment. However, if this requires excessive adjustment that interferes with the frame's appearance, you may need to remake the lenses with a lower seg placement and that may create a new set of issues with frame selection. This is where following correct procedures from the very beginning, even though they may slow you down a bit, could pay off by saving you money and saving your customers time and aggravation

Non-specific complaints, just general dissatisfaction may mean that the customer has had second thoughts about the frame or is reacting to comments by friends or family. Just listening to them and re-evaluating and validating their choices may solve this one.

NON-STANDARD APPLICATIONS FOR SHORT-CORRIDOR PROGRESSIVES

Most non-standard applications for short-corridor lenses are anecdotal, but can plant some seeds for future use.

Discuss with the prescribing doctor the use of short-corridor lenses with children who are being fitted for bifocals. The advantage here is that there is no line for them to try to avoid, the prime reason bifocals are fitted so high in children's frames. Theoretically, the eye is drawn down the corridor to the reading area.

Suggest using short-corridor lenses in elegant small frames for those events requiring evening dress.

Short-corridor lenses may be an option for sports where a bifocal is only necessary for reading a scorecard, such as golf.


SUCCESS WITH SHORT-CORRIDOR PROGRESSIVE LENSES

Your customer's success with short-corridor progressive lenses hinges on a few important key points.
  • Know your product. Know what lens designs are available, in what materials and in what parameters.
  • Listen to your customer's needs and wants, paying careful attention to previous wearing experiences.
  • Describe the features that will address those needs and wants, being careful not to over-promise lens performance.
  • Pay careful attention to frame selection and fit. Don't rush the process.
  • Verify finished eyewear before dispensing.
  • Carefully adjust the finished eyewear and instruct your customer on its use and care.

Schedule a follow-up visit to check their progress.


In short, and I meant that pun, this new lens category offers a realistic solution to the problem of designing fashionable and functional eyewear.


That’s it!…as always, hope this helped someone, feel free to leave comments or questions.
Ben Ramsey…aka MobileEyeGuy

info@FactoryDirectEyeglasses.com

Factory Direct Eyeglasses.com

8 comments:

  1. Did you know there is a new short corridor option in polarized. iRx Short is available in Poly and 1.56 materials and 12 color choices. Minimum fitting height is 14mm.

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  2. Mary Turzillo9:10 AM

    I have worn progressive lenses for about ten years and have had no problem with them up to now. But now I have a new prescription and it is identical to the one in the glasses I have now. However, the glasses which were dispensed to me seem to have the corridor (is that the right word for where the intermediate vision script starts?) too high. The bottom of a movie screen is blurred, as are street signs in the near distance and friends' faces in the near distance.

    I asked the optician when I selected the frames if there would be any problem with the ones I selected, and she said no. However, I really can't wear these new glasses. I think the corridor is placed too high, and I think this is because the young lady fitting the glasses and marking my pupils keeps wanting me to dip my head down in what for me is an unnatural position when she fits them.

    I took them back, but again she wanted me to duck my head down as she marked my pupil, and again she said she could not lower the corridor for my comfort.

    Am I being unreasonable? When I complain, she says I just have to adjust and that she has been doing this for ten years and I shouldn't look at material on the internet to help with my problem.

    These glasses cost me over $500, and I made the mistake of paying the entire amount up front.

    Any advice?

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  3. Mary Turzillo7:59 AM

    Here's an update -- the optometrist, who I very much trust, called me yesterday and asked me a number of questions about my vision and field of vision, and the update is that they CAN lower the corridor, and they will. So I think this will fix the problem.

    It's all very well to speak in theoretical terms, but people have to be able to walk around and function in progressive lenses. It looks like a caring practitioner is making this possible for me.

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  4. Interesting review, I'm the kind of guy who sticks with what had been working, I'm still using the not that big kind of frame from the 90s.

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  5. I just got some new glasses the other day with progressive lens. These are my first pair. I have to say, I don't like them. I can't see anything with these things other than distance. I have to take them off to be able to ready the computer screen. In my opinion, I think the reader part of the lens should be wider as well as middle part of the lens. Looking through the lens in these areas only show a focus point of what I am looking at while everything around the text or computer screen is completely blurry. I use 3 monitors at work and these glasses just won't do for what I need to do. I can see the text on the computer screens plain as day when I take the glasses off. I tried to explain that to the eye doctor but she said I had to get used to them. What is it I have to get used to? NOT seeing? lol.. I truly can't see anything close with these things.. its all blurry no matter how I shift my head. I'll probably be taking these overpriced glasses back in about a week..

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  6. Whereas
    My eyes are 55 and they are used to certain comforts, and
    I do not tolerate change as well as I use too, and
    I am getting older and my vision is getting worse, and
    I have been wearing progressives for over 10 years now:
    It is not a good idea to switch to progressive lens that are smaller.
    Do not go from a regular progressive lens to a short(er) corridor lens

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  7. I will definitely share this site with my friends. Thanks for sharing.I will keep visiting this blog very often. Thanks.
    Fashion Questionnaire

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  8. Anonymous1:47 PM

    I've been wearing progressives for around 10 years now, and I have had a lot of trouble with them. I've been to three different optometrists. The first one gave me the wrong prescription, and the lenses they gave me (I found out later) were two different brands! which is a BIG No No. Once I finally got the right prescription, made right it took 7 adjustments before I was comfortable. The first week I get so frustrated I want to run over them with my car. Then every time the frame changes position from wear and tear my eyes start to strain again.There has to be a better anser out there!

    ReplyDelete