RxPertise: Fitting In

Photos by Peter Zuzga

By Brian P. Dunleavy                                           
For David Ziegler, OD, a career-long devotion to progressive lenses can be traced to his days as an optometry school student. No one knows for sure when no-line bifocals became a part of the standard curriculum at optometry schools in the U.S., though optical industry veterans say instructors first mentioned the technology in the mid- to late-1960s, and then only briefly. It’s safe to say, however, progressives didn’t become a focus of lens curriculums until the late 1970s. As a 1981 graduate of the Southern California College of Optometry in Fullerton, Calif., Dr. Ziegler was part of one of the earliest generations of optometrists to study progressives as the ideal lens option for presbyopic patients.

“Progressives were the multifocal lens of choice for my practice right out of optometry school,” recalls Dr. Ziegler. “We were trained that progressives were the way to go for presbyopes. Today everyone is a candidate for progressives until proven otherwise. Sometimes our staff might be reluctant—especially, say, if a 70-year-old bifocal wearer walks in. But we tell our staff that our goal is to get everyone into the best lens possible.”

Since opening his Milwaukee-based private practice, Ziegler & Leffingwell, in 1981 (partner Chapman Leffingwell, OD, came on board in 1991), Dr. Ziegler has become a noted expert on progressives and lens technology in general. He is a Fellow of the American Academy of Optometry and an associate clinical professor to the Southern College of Optometry and Pacific University College of Optometry. He also serves as the team optometrist for several professional sports teams. In all of these capacities, he lectures frequently on the topic of progressive dispensing. The optometrist says the keys to successful progressive dispensing lie in pricing/positioning and fitting. And he must know: More than 85 percent of the multifocals his practice dispenses are progressives.

The practice uses a three-tier pricing system for multifocals based on the lens materials and treatments sold with the lens. The pricing system starts with the top-of-the-line “Premium Lens Package,” which includes a premium progressive lens in high-index plastic or polycarbonate with anti-reflective, UV protection and scratch-resistance treatments. The next level—the “Advanced Design” package—is the same premium design lens, without A-R. The third and lowest level—“the Standard Lens” package—is a flat-top bifocal with scratch-resistant coating only. Specific pricing for the three categories was not disclosed. Dr. Zeigler and his staff research lens products constantly. When he lectures, he advises his audience to do the same.

“We’ve done some studies with other designs where we’ve even fit 20 or so patients with a new product—of course, we tell them what we’re doing first—and we get their feedback,” he says. “It’s important to find the lens or lenses that work for you. It depends on your practice and your patients.”

And it’s this issue of fitting that has Dr. Ziegler more involved in the dispensing process than most of his optometric colleagues. Because his progressive dispensing philosophy relies so heavily on fitting, he has developed a protocol for his optical staff to follow.

The considerations, he says, start at the frame boards. With short-corridor lenses not an option in his shop progressive patients are limited to frames with a minimum fitting height of 18mm. This range still encompasses a large number of the smaller frame styles popular today.

Once patients have selected their frames, the Ziegler & Leffingwell dispensing staff have been trained to make any frame adjustments first, before the lens is even considered. “You want to ensure the frames fit comfortably and correctly first,” Dr. Ziegler says. “Adjusting the nosepads later, for instance, after the lenses have been put in, can change where the near and distance zones are relative to the eye. When you’re fitting the lenses later on, you’ll want to have the zones positioned ideally for how the wearer will use the lens.”

Dr. Ziegler’s dispensers are also trained to fit the frames of progressive wearers as close to the face as possible. According to the optometrist, finished eyewear should be fit with 15 degrees of pantoscopic tilt (the angle at which your glasses sit before your eyes that allow your eyes to track upward and downward with minimal distortion). This enables patients to easily scan up and down the lens when moving from near to distance and back again.
Having a fit: Dr. Ziegler’s dispensing staff asks patients to assume a “habitual position” during fitting. The idea is to fit PALs for actual wear conditions.
Once they’re ready to consider the lens portion of the eyewear, the practice’s dispensers want to measure the patient’s monocular pupillary distances as accurately as possible. To do that, Dr. Ziegler recommends using a pupillometer. “PD sticks just aren’t accurate enough,” he says. “You can be more than a half millimeter off.”

Next, when marking where to place the fitting cross of the progressive lens, dispensers are told to ask what activities the wearer will most often use their lenses for—i.e., driving, computer use reading or watching TV. Instead of positioning themselves across the dispensing table from the patient, and asking the patient to lean over the table, looking straight ahead and place both elbows on the table (as most dispensers do during fitting), Ziegler & Leffingwell dispensers ask patients to position themselves as if they were involved in their desired tasks.

“The dispensers then approach them and mark the lens accordingly based on the position of the patient’s head and eyes,” Dr. Ziegler says. “We call it the ‘habitual position.’ It’s vital in determining fitting height, where a millimeter or two can make a big difference.” Indeed, as the optometrist says, a high fitting height will impair the wearer’s vision; a low fitting height will make it so “they have to work too hard to even get to” the add.

The system must work. According to Dr. Ziegler, the rate of progressive non-adapts in his practice is less than 3 percent.

“There are a lot of great lens designs out there,” he says. “But dispensing them properly involves more than the quality of the lens. Our philosophy here has been to find a design that works for us and then rethink how it’s fit and dispensed so that we’re giving the patient the best vision possible. It’s worked for us so far.”