Dan Katzman designed his first progressive lens in 1984. Since then, as chief of engineering and lens design for Shamir Optical Industry, the Israeli company best known for its high-quality progressive lenses and molds, he has emerged as an influential behind-the-scenes figure in the field of ophthalmic lens design and manufacturing. His innovative Eye Point Technology serves as the basis of some of the company’s most successful progressive lenses, including the Genesis and Piccolo. Katzman has also created distinctive lens designs for other manufacturers.
In this rare interview, Katzman shares his view about the current state of progressives and discusses the potential for some promising new technologies for manufacturing and dispensing the lenses.
You’ve been designing lenses for 20 years. How do you approach the design of a new lens?
It’s complicated. The size and the shape of the frame are major factors that influences the design of the lens. Then you have to consider what market sector it’s intended for. You have people who are ready to spend a lot of money and some who aren’t.
The newest generation of progressives is quite sophisticated. Are we reaching the limits of progressive lens performance, or is there still room for improvement?
Things that were considered to be close to the limit a few years ago have been achieved. That gives me encouragement that if we keep on digging into this subject, which we are, we will be able to generate new ideas and new algorithms and improve our design tools. Progressives can still be improved with and without the “individual” designs that are customized for each wearer.
But it won’t be enough to just improve the lens. We have to consider the progressive as part of a lens system that includes the person, the frame and the lenses — in that order. Every one of us is different; we don’t necessarily take the same frame. You can only fully optimize the lens design when you factor in the other two components first.
What is your assessment of “freeform” or “direct surfacing” of progressives? How can this technology benefit eyecare practitioners and their patients?
[Editor’s note: The term “freeform” refers to the technique of using advanced generating technology to put complex aspheric, atoric or progressives surfaces on the front or back of a lens blank to create a more customized prescription.]
Freeform technology enables a specific optimum design or lens topography to be created for every prescription and wearer. The patient will adapt sooner and will enjoy easier usage of the lenses.
Shamir is the first lens manufacturer to supply a “points file” with proprietary progressive lens design data to suppliers of freeform surfacing equipment. This represents a significant change in the manufacturing and distribution of progressives. Is this the way of the future? If so, how soon do you expect other lens and equipment companies to follow?
Shamir sees freeform technology as the future way to sell lenses. We want to maintain our position as a source of very good optical designs.
Freeform technology will be slow to spread. There will still be a lot of labs that will not invest in it because of the price, or because they’re afraid to be responsible for the optical characteristics of the product. They’ll need to have measuring instruments that are relatively simple to use. Until this is very well established, we’ll see labs a little afraid to jump into this market.
As progressive lenses become more sophisticated, what knowledge and skills are required of eyecare professionals in order to dispense the lenses more effectively?
If a patient cannot adjust to wearing a progressive lens, it is usually because they had a poor fitting. If the fitting was perfect you could better differentiate the level of optical design to see which lens works best for the patient.
for a progressive, opticians will need to be able to supply more detailed information about the lens system. For example, they’ll need to measure the way the frame is sitting on the patient’s face and the actual position of the pupil in the frame. We need measuring equipment that will enable opticians to accurately do these types of fittings. There should be some type of closed loop to enter this information into the measuring system to monitor accuracy.
The reason this technology is not in optical shops yet is that no one has yet come up with a simple, automated fitter. Lens manufacturers are struggling with designs, but the industry is not providing sophisticated fitting equipment. It’s only in the first stages of development. Opticians should ask the equipment companies to make this a priority.