L&T: Lens Choices

Feb
2002

Task-Specific Specs





Photo by Nedjeljko Matura


Task-Specific Specs

At work or play,  there are lens options available  for a variety of activities

by Brian P. Dunleavy

 
Historically, lens manufacturers and eyecare professionals alike have eschewed the term “task-specific” when discussing spectacle products. All eyes, after all, are different, and how they adapt to various environments and conditions varies from person to person. The last thing any optician, optometrist or ophthalmologist wants to do is fit or prescribe lenses to a patient with the promise that “these will definitely work for you,” only to have them return a few days later frustrated and looking for a refund.

In the latter 1990s, however, this philosophy started to change. With consumers now more conditioned to specialization in other product purchases, it has become easier for dispensers to position specific lens products to individual needs. It hasn’t hurt that, thanks to vastly improved research and development technology, lens manufacturers have been able to deliver products offering select visual properties ideal for certain settings.

“Task-specific lenses are the future of our industry,” notes one lens executive. And they are also a pretty good source for lucrative second-pair sales at the dispensary level.

So what are some of the products available?

Trifocals   Trifocals are hardly new, of course, but because they offer near, intermediate and distance segments in one lens, they have in recent years been considered ideal for a wide variety of occupational tasks, particularly those requiring both near vision and overhead vision. Examples include tradesmen such as plumbers, painters, carpenters and electricians as well as airline pilots. Some dispensers still favor trifocals—even with the advent of no-line multi-focals—because they offer wider near and intermediate zones and less peripheral distortion.

In recent years, with the growth of computer usage in the workplace and home, dispensers have also been prescribing trifocals for patients who use computers for extended periods of time. The trifocal lens’ wider reading and intermediate segments are useful in office settings because they allow the wearer to see the computer screen (which is typically positioned roughly three feet away) as well as visual targets positioned as far as 10 to 12 feet away (such as visitors in their office or bulletin boards on their office wall).

“Computer” lenses   Of course, since 1998, several lens manufacturers have sought to address the computer issue with a more modern solution—computer vision lenses. These no-line lenses offer enhanced near and intermediate vision.

Several lens manufacturers now offer products that fit into this emerging category, including Prio, Rodenstock, AO/Sola, Shamir, Hoya and Zeiss. Advocates of these lens products believe that they are the solution to computer vision syndrome (CVS), the eyestrain or fatigue computer users often feel after extensive time behind the keyboard.

Both presbyopic and single-vision plus and minus patients have benefited from the use of “computer lens” products in occupational settings. In addition to computer users, wearers in other occupations may benefit from their use, including architectural drawing and drafting, writing and any artistic endeavor such as painting and sculpting.

“Distance” progressives   Computer vision lenses are only the first in what may become a variety of “task-specific” lenses in the progressive category. AO/Sola, for example, recently introduced B’Active, a progressive with reduced distortion in the periphery of the distance zone designed for active presbyopes. The ideal wearer would be a weekend athlete (i.e., a tennis player) who may need to see a projectile coming toward them from a distance.

Coatings and Treatments   Vision concerns in the workplace encompass more than what the patient needs to see. They also include where the patient needs to see. Issues such as desk position, computer position, lighting and chair height can affect patients’ vision because eyes adapt to their environment. Patients may need treatments and add-ons such as ultraviolet (UV) treatment, anti-reflective (A-R) coating and lens tints. Dispensers generally use these products for patients working in environments where fluorescent lighting is in use. Fluorescent lighting, they say, contributes to eye fatigue because of its high UV content.

Outdoor occupations such as construction work and farming can benefit from polarized polycarbonate lenses because they offer both the impact resistance needed for safety and the sun protection needed for healthy vision. Polarized sunlenses have also become a particularly popular lens option among athletes because they are specifically designed to reduce or eliminate reflected glare off surfaces such as roads, snow, water or ice, making them ideal for activities such as water sports (i.e., boating or fishing) as well as driving.

Polycarbonate   Because of its inherent impact-resistance, polycarbonate has become almost synonymous with occupational safety eyewear. This same trait has also made it the predominant lens material for sports use. PPG, meanwhile, has developed an entirely new lens material called Trivex, which it claims has the same impact resistance as poly, but a higher Abbe Value for improved optics. One of the most important developments in the sports lens arena in recent years was the introduction of polarized polycarbonate lenses in the mid-1990s. Athletes wearing these lenses benefit from both the glare reduction of polarization and the impact resistance of polycarbonate. Because the film is added to the base material when it is still in liquid form (as opposed to laminated on the surface of the lens), polarized polycarbonate lenses tend to be more durable than polarized lenses made from other materials.

Tints   Researchers still disagree on the importance of tinted lenses on the playing field or in the workplace, but studies have shown that some colors do have an impact on visual performance. Many believe certain tints benefit those working in light industry, such as welders, by reducing the strain on the eyes caused by glare. Tints applied for sports-specific applications, meanwhile, should act as filters, reducing the overall amount of visible light reaching the athlete’s eyes while, in some cases, filtering out specific wavelengths of light. Some lens tints also enhance contrast sensitivity, allowing the eye to see greater definition between colors. Yellow tints, for example, are said to brighten low light situations and improve contrast, which makes them a favorite of skiers and sport shooters.

Research and development in the area of task-specific spectacle lenses is hardly finished. In fact, executives at most lens companies say the work has only just begun. With so many opportunities to create additional sales for their dispenser customers—and so many opportunities for dispensers to better serve their patients—expect further product launches in this area in the near future. 

the lens list

ESSILOR INTRODUCES PANAMIC THIN & LITE Essilor has released Varilux Panamic Thin & Lite—a 1.67 high-index plastic lens. According to the company, this thinner progressive addition lens is available with Crizal A-R coating. It is the first aspheric lens available in Varilux.

YOUNGER EXPANDS TRILOGY Younger Optics has introduced its Image progressive lens in Trilogy, the company’s version of the new impact-resistant plastic material from PPG Industries (Trivex) that features an Abbe Value of 45. Image is now available in 14 materials. The lens fits virtually any size frame, with fitting heights as short as 18mm.

SEIKO LAUNCHES INTERNAL Seiko Optical has released the 1.67 Super Proceed Internal. The lens is available in an Rx range of +6.00D to –10.00D out to a –4.00D cylinder. Available adds are from +0.50D to +3.50D (in 0.25D steps). According to the company, the lens can fit to corridors as short as 12 to 14mm.

ZEISS RELEASES GRADAL TOP POLY TRANSITIONS Zeiss is expanding its Gradal progressive line with the release of Gradal Top 1.59 Poly in Transitions photochromic gray. The lens is available in an Rx range of +4.50D to –6.00D out to a –4.00D cylinder, with adds of +1.00D to +3.00D.

PENTAX RELEASES POLY PAL Pentax has expanded its line of short-corridor progressive lenses with the release of the DC Mini polycarbonate lens. Designed for minimum fitting height of 17mm (14mm corridor length), the DC (Diamond Clear) Mini is available in an Rx range of +7.25D to –7.50D out to a –4.00D cylinder, with +1.00D to +3.00D adds.

 

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