It's a PAL jungle out there. Just open up the 2006 edition of the Optical Laboratories Association Progressive Lens Identifier catalog and you'll see no less than 307 different PAL (progressive addition lens) designs. That’s a bewildering number of choices for any doctor or dispenser. There are PALs for everyday wear and for computer use, short-corridor PALs for smaller frames and PALs with wider near, intermediate and far viewing areas. There are PALs for emerging presbyopes and former bifocal wearers. There are PALs made of every possible lens material and featuring every type of lens treatment.
Although cutting through the clutter to find the right PAL for a particular patient can be difficult, it can also be rewarding for both patient and practitioner. Patients are often delighted if their vision improves after wearing a PAL that is matched to their individual viewing needs.
Matching a patient with the right PAL requires a thorough understanding of the latest product features and corresponding benefits. One recent trend in PAL design is customization or personalization. Armed with powerful new designs, manufacturing and dispensing technologies, lens suppliers are introducing a new generation of PALs that are optimized for individual wearers. Utilizing an array of new measuring devices and computer design techniques, several leading PAL manufacturers have overcome the limitations of standardized front surface designs in a series of base curves to create personalized PALs that promise the ultimate in visual performance and comfort.
Another new trend involves the use of wavefront technology to minimize higher order aberrations and otherwise improve optics.
Eyecare professionals must not only be familiar with the growing number of PAL options, but also be able to select the best lens design, material and treatment for the presbyopic patients.
Lately, the most talked about development in PAL design is free-form or direct surfacing. Although the term is sometimes used incorrectly to describe lenses, free-form is actually a manufacturing technology that enables PAL manufacturers to precisely shape both the back and front lens surfaces to create designs to optomize the wearer’s vision. In its most sophisticated application, some lens manufacturers also use the technology to customize the PAL design by taking into account the fit of a patient’s frame or their head and eye movement. Among the growing group of PALs made with free-form manufacturing are Seiko’s Super Proceed internal progressive, Carl Zeiss Vision’s SOLAOne HD and Zeiss Individual, Varilux Ipseo, Varilux Physio and Varilux Physio 360° , Hoyalux iD and Shamir Insight’s Autograph and Creation lenses.
Another new dimension in PAL design involves wavefront technology. Used in both refractive surgery and contact lens design, wavefront measures the light waves entering either the eye or the lens itself, depending upon how it is applied. Varilux Physio and Varilux Physio 360 from Essilor of America were both designed with wavefront technology.
Ophthonix is also using wavefront as a platform for designing PALs. At International Vision Expo East in late March, Ophthonix executives announced the launch of the company’s first iZon customized progressive lens using wavefront-guided technology. The iZon technology detects and corrects for the unique aberrations of the eye, addressing all potential refractive errors including higher-order aberrations.
There are two musts when it comes to matching the right PAL to the right patient: Product knowledge and patient knowledge. You can gain product knowledge by reading trade magazines and perusing manufacturer information on PALs. Ask the manufacturer for its “white papers,” which give very specific data on its products. Have your lab or lens rep come to your office on a regularly scheduled basis in order to obtain product updates and information on new products as soon as they’re introduced. You can even ask for additional education on specific topics, such as PALs, when you bring in new staff members or to refresh the office outlook.
Patient knowledge can be obtained by having the patient fill out a lifestyle questionnaire. Lifestyle questionnaires are available from many sources including the Vision Council of America (VCA). Ask open-ended questions—which can’t be answered with a simple yes or no reply—to determine the patient’s specific visual needs. Write down all patient information, keep the information on file and be sure to update it each time the patient comes in, as job and leisure activities may call for a new lifestyle profile.
Present PALs in a good-better-best format. Under a good scenario, you may offer a basic PAL with ultra-violet protection and scratch-resistant coating. The better PAL package may offer a premium material such as a high-index plastic with UV and SRC, and the best PAL offering would include all the previous perks plus photochromic and/or anti-reflective coating. Warranties can coincide with your good, better, best lenses, such as a good one-year, one-time replacement, a better one-year warranty with unlimited replacement, or best, the lifetime of the lens.
Don’t forget that in addition to their everyday PALs, many patients may require a second pair for specific use. Someone who works on a computer more than two hours daily would benefit from a computer-specific PAL. A draftsman, architect or anyone who works at arms length may prefer a PAL with a wider intermediate zone, while a patient who is an avid reader would be better-served by a PAL with a large reading area. And someone active in sports may need a progressive with a wider peripheral viewing zone. There is a PAL to fulfill every lifestyle need and often multiple needs with the same patient.
Short-corridor PAL designs help dispensers fit patients who want smaller fashion frames in a workable PAL. These PALs have been designed to accommodate fitting heights from as low as 12 to 18mm. Short-corridor PALs are ideal for those with small faces that can’t wear large frames. In fact, some dispensers are fitting children and teens who require bifocals into short-corridor PALs instead.
Professional/occupational PALs such as office and/or computer lenses offer larger reading areas and wider and larger intermediate zones. Some occupational PALs offer indoor distance vision (to view a clock on the wall, for example) plus intermediate (computer screen) and near (desktop) viewing, while some office PALs offer intermediate and near vision only. Check with the manufacturer to be sure of its office PAL capabilities.
Combining the right material with the right PAL can turn an everyday PAL into a patient-pleaser. For example, a high-index aspheric PAL furnishes a thinner, lighter, flatter lens with less aberration, ideal for a high-plus or high-minus Rx. A polycarbonate or Trivex PAL for active presbyopes ensures the best lens protection. And glass PALs, now a viable option with smaller frames and higher indices, offer visual clarity for those who want the clearest, crispest vision. Add an AR coating to any PAL lens material and the visual and cosmetic benefits are enhanced even further.
For those patients who are active in sports or other activities there are several PAL options. A PAL with a wide central viewing area and enhanced peripheral vision helps active patients see in areas where they need the most visual concentration. A photochromic PAL can be of benefit to golfers who experience a wide range of visual conditions—the morning fog and haze to partly cloudy to cloudy skies—while they are on the course. Some dispensers measure photochromic PALs extra-low for better putting ability and furnish their golfers a sun lens clip-on for full sun.
As the consumer trend toward individualization grows—especially in the presbyopic Baby Boomer demographic—so will the demand for individualized solutions. Improvements and enhancements to PAL products as well as the introduction of additional specialized PALs to the marketplace can be expected. Be sure to keep abreast of PAL developments in order to be able to fulfill your patients’ many needs.