PRECISION VISION
Curve-conscious freeform lenses are taking performance to a whole new level
By Karlen McLean, ABOC, NCLC
Illustration by Eric Fortune

Freeform-created lenses continue to grow the lens marketplace by introducing never-before-experienced technology that can program lenses to the highest degree.

When categorizing freeform, it's important to note that freeform is a way to produce lenses and that freeform-designed lenses are the result of the process. Because each lens is individually created to specific, computer-programmed parameters, freeform isn't a particular lens design or style; true freeform is a process that customizes each lens for the best possible vision.

Although they constitute a small portion of lenses produced today, this
latest development in the lens arena is likely to be the largest in the future. Many manufacturers, labs, and ECP experts predict that freeform will be the only way that lenses will be produced within 10 years.

JUST THE FACTS

1. Base curves are no longer selected from stock parameters; base curves are created for each individual lens.

2. Individualized wearing habits, such as visual tasks and head and eye movement, are combined with the Rx to create each lens.

3. Success with first-time wearers and previous non-adapts increases dramatically, since lenses adapt to patients' habits, not the other way around.

4. Expansion of the visual field for all distances helps reduce peripheral blur with less "swim."

5. Larger and wider intermediate zones help make PALs more user-friendly.

6. Aspheric and/or atoric curves fine-tune vision in all zones, plus flatten and slim lenses for improved cosmetics and comfort with less weight.

7. Fitting heights in the mid-teens accommodate most of today's small fashion frames.

8. Computer-driven production allows for the most precise lens possible.

9. Many freeform PALs are based on long, intensely detailed market research and clinical studies, making it easier to substantiate one-of-a-kind design to patients.

While dispensing freeform PALs may require new training or brush-up in optical measurements and in the use of specialized measuring tools in some cases, the ultra-personalized lenses that result should satisfy even the most persnickety patients and win new friends.

And while freeform PALs currently reside at the high end of retail lens pricing and can require a longer turnaround time, savvy dispensers who market these lenses as the "best to the best" should find freeform success.

LENS LINEUP

Currently these companies offer freeform PAL lens products in the U.S.: 

Company:
Carl Zeiss (Carl Zeiss Vision)

Contact information:
800-338-2984, www.zeiss.com/lenses

Products:
Gradal Individual and Gradal Short i

The Zeiss Gradal Individual and Gradal Short i progressive lens designs are both created using freeform technology, offering "clarity, superior adaptability, and optimized wide viewing areas with virtually no distortions," according to company sources.

After calculation, the progressive surface and back
surface are three-dimensionally freeform diamond cut to shape, polished, and AR-coated. ECPs specify Rx, PD, fitting height, corneal vertex distance, pantoscopic angle, near distance, and frame shape to totally customize the lens.

A Zeiss Gradal Individual Fitting Tool helps verify the back vertex distance and pantoscopic angle. A "zero" mm inset for monocular patients and specification of individual near working distance can further customize the lenses.

Minimum fitting heights are Gradal Individual: 18mm (for traditional frame sizes); Gradal Short i: 15mm (for small frame sizes). The lenses are currently available in 1.60 material with Zeiss Carat coating.

Gradal Individual and Short i lenses are produced in Chester, Va., and can be ordered from participating CZV Partner laboratories.

Company:
Essilor of America

Contact information:
800-377-4567, www.essilorusa.com

Product:
Varilux Ipseo

Essilor's Varilux Ipseo freeform progressive lenses incorporate Essilor's Vision Print System (VPS). The company provides ECPs with a VPS diagnostic device to measure unique wearer characteristics, including eye/head movement ratio, and a stability coefficient. Combined with the patient's Rx, these measurements create a progressive surface specifically suited to the individual wearer's needs, according to company sources.

Design specifications take into account patient categories of eye movers versus head movers, with modified corridor length to compensate for the prismatic effects of the distance Rx and add power. Head movers tend to be affected by lens swim, and require softer and slower variations of power in the periphery, while eye movers receive an astigmatism-free area up to 60-percent wider than the design's baseline.

Varilux Ipseo had been Beta-tested in select U.S.
markets and was launched nationwide this year. The lenses will be available through Essilor laboratories in Thin & Lite 1.67 Crizal Alizé AR. Minimum recommended
fitting height is 18mm. For further customization, the patient's initials are engraved on the lens.

Company:
Essilor (formerly Johnson & Johnson Vision Care)

Contact information:
800-920-2021, Ext. 3700, www.definity.com

Product:
Definity Lenses

Definity PALs decrease traditional PAL distortion and swim, and provide sharper and wider vision through a patented Dual Add technology and a proprietary freeform manufacturing process. The Dual Add technology reduces unwanted astigmatism by dividing and offsetting the progressive optics between the front and back surfaces of the lens. Lens performance is backed by extensive clinical and marketplace testing.

Additionally, Definity lenses feature a Fourth Zone in larger frames. The Fourth Zone is located beneath the near zone, reducing the near add power to provide clearer vision when looking downward. Recommended fitting height is 18mm, but to best utilize the Fourth Zone, recommended fitting height is at least 22 mm.

The lenses are available with Gemcoat multicoating, a premium AR and scratch-resistant technology, and currently come in CR 39, polycarbonate, Transitions 1.50 gray, and high-index 1.60.

Freeform PALs offer a high-end lens option for the "best of the best"

Company:
Rodenstock North America

Contact information:
888-407-3937, www.rodenstockusa.com

Product:
Multigressiv 2

Rodenstock labels the Multigressiv 2 as the world's first tailor-made lens. "It is a distinctive alternative to conventional progressive lenses because it is custom designed to match the unique characteristics of each wearer," according to a company source.

The Multigressiv 2 is a progressive lens created by a complex, computer-driven mathematical formula, which determines the precise combination of curves to optimize each lens. The lenses feature a fully aspheric front surface with optimized atoric curves on the back surface, allowing a smooth transition from distant to near focal points, a wider reading area, and enhanced peripheral vision.

Recommended fitting height is 18mm. Multigressiv 2 is currently available in 1.50 plastic, ColorMatic Extra photochromic grey or brown in 1.52, and 1.60 high-index.

Multigressiv 2 lenses are manufactured at Rodenstock's high-tech facility in Regen, Germany, and are available with scratch-resistance and AR.

Company:
Seiko Optical Products of America

Contact information:
800-235-5367, www.seikoeyewear.com

Product:
Seiko's 1.67

Super Proceed Internal places the progressive power on the back of the lens via freeform technology. The front surface is spherical. The freeform surface on the back of the lens is fused with a toric Rx-specific surface into a single complex curve. Then aspheric compensation for each Rx (sphere, cylinder, axis, and add) is added, eliminating power errors. This technique also ensures an expanded field-of-view, visual stability, and reduction in skew distortion, swim, and sway, according to company sources. More than two million unique lens combinations are possible.

The Seiko 1.67 Super Proceed Internal is available in two different minimum fitting heights: 18mm and 16mm. All lenses are provided with Seiko high-impact factory AR.

Seiko 1.67 Super Proceed Internal lenses are available through Authorized Seiko Distributors.

Contact information:  
888-707-7760, www.shamirlens.com

Product:
Autograph

Based on Shamir's Eye Point Technology, which
simulates the human eye at every angle of vision using a simulation of the human eye, the Autograph additionally utilizes Shamir's advanced Direct Lens Technology software program to design the optical power into the back of a
single vision semi-finished lens to combine the patient's Rx with the needs of a personalized PAL.

The correct file for each patient's needs is automatically selected from Shamir's unique Prescriptor Freeform software database. Thus, the lenses provide personalized design for every angle, vision zone, and Rx, resulting in enhanced peripheral vision, binocular vision, and visual clarity, according to company sources.

Autograph is aspheric in all vision zones, creating a lens that is as thin as possible. The company recommends a minimum fitting height of 19mm.

Autograph is currently available in standard plastic and 1.60 SuperLite. The lenses can be ordered from ReCreating Perfect Vision Shamir partner laboratories.

Company:
Signet Armorlite

Contact information:
800-950-5367, www.signetarmorlite.com

Product:
Kodak Precise

The Kodak Precise PAL incorporates Vision First Design technology, which controls the lens curvature at all points to optimize visual acuity. The lens surface power increases gradually and smoothly from top to bottom throughout the central and peripheral zones, and features a Zone of Maximum Use, which puts the full add power in the precise spot for optimized reading use.

The lenses feature a wide customized near zone for natural movement in up-close activities, a smooth transitional intermediate zone, and a clear, wide distance zone. A peripheral zone offers smooth power progression and binocular balance which helps eliminate swim, according to company sources.

Kodak Precise Lens is currently available in KODAK InstaShades 1.56 and 1.6 gray and brown, Corning SunSensors 1.56 gray and brown,, 1.56 and 1.6 EvoClear, and 1.67 high-index, PolyClear, PolarShades gray and brown, and standard plastic with scratch resistance.

Company:
SOLA Optical North America (Carl Zeiss Vision)

Contact information:
800-358-8258, www.sola.com

Products:
SOLAOne HD and AO Easy HD 

Utilizing SOLA's HD (High Definition) technology, which delivers a more accurate Rx in the position of wear, every SOLAOne HD and AO Easy HD lens is individually designed for the specific Rx requirements of each wearer, so that every wearer receives the best vision possible regardless of Rx.

Most wearers will experience larger areas of clear vision than would be possible with a conventional PAL.

The lenses offer a balance of central and peripheral vision that is based on 10 years of vision research and developmental wearer trials, as well as ongoing studies on understanding PAL lens wearers' visual tasks.

The result is a progressive addition lens that "performs better in the full range of common visual tasks," according to company sources. The design features a larger and wider intermediate area and a large, high, wide near zone for a variety of reading tasks.

Recommended minimum fitting height for both lenses is 18mm. The SOLAOne HD and AO Easy HD lenses are currently available in 1.67 high-index lens material and Teflon Clear Coat AR is included automatically. In addition, SOLAOne HD and AO Easy HD can be ordered as a complete Rx from any lab.

While advanced freeform generators produce the front-side glass molds required by ultra-sophisticated progressive lens designs, both lens manufacturers and laboratories that invest in this high-tech equipment are dependent on software that interfaces with the equipment to create a freeform lens.

This proprietary software, known as a "points file," enables the lens manufacturer or lab to create personalized progressive lenses to their specific design specifications by independently calculating the parameters of each lens. The points file is transferred to a freeform generator, which cuts and polishes the lenses using a precise single point diamond tool and "point" polishers.

Multi-curve surfaces are necessary to produce freeform lenses; computer controlled freeform machinery can apply non-conventional progressive surfaces on the front, back, or the front and back of a lens, depending on the manufacturer's design requirements. A points file is only used once, as each is programmed to the patient's specific Rx and measurements, making every lens a truly individualized creation.

Currently there are four companies that manufacturer and supply freeform equipment to the U.S. optical marketplace:

Company:
DAC Vision

Contact information:
800-800-1550, www.dacvision.com

Products:
RxD Lathe, Soft Lap Polisher

The RxD Lathe is cut-to-polish technology featuring a four-axis diamond turning lathe for spectacle lens back surface generation. The Soft Lap Polisher, used in conjunction with the RxD lathe, effectively polishes highly precise lenses.

Company:
OptoTech Optical Machinery, Inc., a subsidiary of OptoTech Optikmaschinen GmbH

Contact information:
215-679-2091, www.optotech.de

Products:
Freeform Generator ASM 80 CNC-TC, Freeform Polisher ASP 80 CNC, smartLAB system

Offering a turnkey solution for small or medium-sized companies, the OptoTech system is fully automated. Features include processing for all lens formats, laser engraving, a software package for in-house PALs including blanks, and measuring technology.

Company:
Schneider Optical Machines

Contact information:
972-247-4000, www.Schneider-om.com

Products:
HSC 101 GT and HSC 101 GTh high-speed cutting generators, CCP101 and CCP102 computer-controlled polishers, CCL100 computer-controlled laser marking unit, CCU 101 computer-controlled utility for taping and blocking.

The Schneider freeform line is fully automatic. The HSC 101 GT is capable of cutting any toric surface, as well as any freeform surface. Schneider's iRx concept incorporates the complete network capability and interfaces with existing lab logistic software.

Contact information:
800-866-5640, www.satisloh.com

Products:
VFT Series All Format Generators, VFT-Ultra for high-production labs (90 lenses/hour), VFT-Compact for smaller labs and specialized freeform cells (40 lenses/hour)

Toric cut-to-polish capabilities can process any polish-ready lens quickly and precisely.