Photo by NEDJELJKO MATURA.
Lens and fitting tool courtesy of Carl Zeiss. Frame: Nautica 7088 from Marchon Eyewear.
By Andrew Karp
One of the most exciting new developments in progressive addition lenses (PALs) is the introduction of “free form” or “direct surfacing” technology. Lens manufacturers are using this technology to shape and, to varying degrees, customize both the front and back surfaces of a progressive lens. These new lenses overcome many of the limitations of earlier PAL designs by offering improved optics with wider, clearer fields of vision, virtually no unwanted astigmatism, easy adaptation and other enhancements.
Several manufacturers have recently introduced PALs in the U.S. that are produced with free form technology, include Johnson & Johnson’s Definity, Carl Zeiss’ Gradal Individual and Gradal Short i, Shamir Insight’s Shamir Autograph, SOLA Optical’s SOLAOne and Seiko Optical Products’ 1.67 Super Proceed Internal Progressive. However, each has distinctly different features and offers unique benefits to wearers. L&T spoke with an assortment of doctors and dispensers to find out what it’s like to wear and dispense these new PALs... and... their patients’ reactions to actually wearing these lenses.
|David Armstrong, OD, Roanoke, Va.: “We have been using Definity with great success. We have around 500 patients in the Definity, with a reject level of only 12 people. The Definity is close to being our exclusive PAL; the other PALs we dispense are for specific use. Both my staff and I wear Definity lenses.|
“We like the Definity because it is easy to show that it is a better lens. Our dispensing routine is to put the new eyewear on the patient, adjust the frames, then have the patient view a width-of-field chart from left to right. The viewing width difference is obvious from their old lenses‚usually different PAL technology‚with a big wow factor.
There is a big field-width advantage at arms-length distance with this lens. I find that the width-of-field is 40 percent wider in the plus-power lenses that I wear, which it is even more dramatic in a minus-power lens due to the flatter base curve. The clear width-of-field advantage is the key attribute of this lens technology.”
MANUFACTURER: Johnson & Johnson Spectacle Lens Group
FEATURES & BENEFITS: Proprietary “Dual Add” technology uses both sides of the lens to create the add power. This distributes unwanted astigmatism over both lens surfaces to create a wide intermediate zone with smooth transitions between distances. Front and back surface designs are different, offsetting peaks of unwanted astigmatism by building up astigmatism gradually in a softer design, which causes less visual swing. Features “fourth zone” in larger frames. Located beneath near zone, it reduces the near add power to minimize distortion and flatten the field of vision, providing clearer vision when patients look down. Seg height must be 22mm or higher to take advantage of this zone of reduced power. Gemcoat multicoating is standard.
MINIMUM FITTING HEIGHT: 18mm (for lenses with a seg ≥ 23 mm)
FITTING PROCEDURES: Standard progressive lens fitting techniques
MATERIALS/RX RANGE: +6.00 to -10.00D sphere (hard resin and Transitions lenses 1.50 gray); +4.00 to -5.00D (polycarbonate) +8.00 to -12.00D (high-index 1.60), with up to -2.00D cylinder in polycarbonate and -4.00D cylinder in hard resin, Transitions lenses 1.50 gray and high-index 1.60. Prism is available up to +6.00D in hard resin, Transitions lenses 1.50 gray and high- index 1.60 (prism range not available for polycarbonate). Adds +1.00 to +3.00D.
ORDERING: Direct from J&J or though Eyefinity and VSP-owned laboratories
|GRADAL INDIVIDUAL AND GRADAL SHORT i|
Kate Giroux, owner, MacPherson Opticians, Arlington, Va.: “We dispense the Zeiss Individual lens, which utilizes free-form technology, on a judicious basis. We make sure that the patient’s personality matches up with the new technology. This lens is well received by our high astigmats and problematic Rx patients. It is also a good lens for our hyper-neurotic patients who want everything just so.
“We personally field test any new product prior to launching it. I am a mid-power myope with a +2.50D add and find that the overall clarity of Zeiss Individual PAL is very good. The Individual is a softer design; it mimics a single-vision lens, which gives a certain level of comfort for wearers. We sell the Individual only as a package with Zeiss Carat AR.”
MANUFACTURER: Carl Zeiss Optical
FEATURES & BENEFITS: Gradal Individual and Gradal Short i consider the Rx for the computation of the lens’ free form surface as well as the patient’s anatomy. Eliminating the need for standard base curve technology, the lenses are produced with a new optical design software technology and CNC tri-axial free form diamond surfacing which combine to generate totally custom-designed lenses. ECPs can specify Rx, PD, fitting height, corneal vertex distance, pantoscopic angle, near distance and the shape of the frame—in order to customize the lens to the patient’s needs. After calculation, the progressive front surface and back surface are three-dimensionally free form diamond-cut to shape, polished and hard and AR-coated. The lenses offer “unprecedented clarity, superior adaptability and optimized wide viewing areas with virtually no distortions,” according to Zeiss. Carat coating (Foundation + Super ET + Clean Coat) is standard.
MINIMUM FITTING HEIGHT: 18mm (Gradal Individual) 15mm (Gradal Short i)
FITTING PROCEDURES: Determine molecuar PDs and fitting heights; specify frame manufacturer, model type and A, B, DBL and back vertex distance andpantoscopic angle.
MATERIALS: 1.60 high-index plastic
RX RANGE: +10.00 to -10.00D, cyl out to
-4.00D; Add: 0.75 to 3.50D. (Gradal Individual); +6.00 to -6.00D, cyl out to -4.00D; Add: 0.75 to 3.00D (Gradal Short i)
ORDERING: Zeiss partner labs
Andrea Reis, optician, Davis, Duehr, Dean optical center, Madison, Wisc.: “We started ‘trialing’ the lens in Spring 2003 with a select group of about 30 people, including doctors, dispenser and patients. Some were emerging presbyopes it was their first pair of PALs, but the majority were presbyopes who had worn different PALs before.
“We did not have a single person say they’re unhappy. Every comment I’ve heard is ‘Wow, I’ve never seen so well.’ They say there’s no swim; their peripheral vision is excellent and they have a bigger, wider reading area. Adaptation was instant; other PALs usually take a day to two to get used to.
“We charge about 20 percent higher for Autograph than for a standard progressive, but price hasn’t been an issue with our patients.
“This is going to be the trend of the future. I see traditional products going by the wayside. So many presbyopes complain of being limited in their glasses. This has really opened up a whole new world for them.”
MANUFACTURER: Shamir Insight
FEATURES & BENEFITS: Shamir Autograph is a new family of progressive lenses based on Direct Lens Technology. Direct Lens Technology is the result of the Prescriptor software developed by Shamir Optical Industry that combines the patient’s Rx data and frame selection with Eye-Point Technology. Eye-Point Technology simulates the human eye at every angle of vision in each optical zone and each prescription range, thus improving accuracy and clarity and ensuring each patient’s angle of vision.
When Eye-Point Technology is combined with the personal “points“ file generated by the software, a personalized progressive lens design with expanded vision zones, precision sphere power and cylinder accuracy is transferred to advanced machinery for the production of Shamir Autograph. Applying the prescription and the progressive design together to the concave side of the lens brings the progressive lens design closer to the eye for wider parameters of vision in every zone.
MINIMUM FITTING HEIGHT: 19mm
FITTING PROCEDURES: Take DBL, PD, plus A, B and C measurements in relation to the fitting cross.
MATERIALS: hard resin and 1.60 high-index plastic
RX RANGE: (hard resin) -8.50 to +4.00D; (1.60) -10.00 to +6.00D Add: 0.75 to 3.50D
ORDERING: Participating Shamir-authorized labs
Betty Jo Landes, optician, Carthage Eye Care optometric practice, Carthage, Mo.: “I have worn every progressive there is, but when I put on SOLAOne, my eyes opened up. The clarity was wonderful at all distances. It’s the same prescription I was wearing, so it had to be the lens. It’s significantly better. As far as I’m concerned, this is the lens I’ll wear now.
“We sell it for the same price as other premium progressives. I can see it being a very successful lens. It has virtually no distortion and my depth perception is wonderful. It’s a good, all-purpose lens. I wear it while climbing ladders and stairs, bowling, golfing, reading, just about everything.”
MANUFACTURER: SOLA Optical
FEATURES & BENEFITS: Generous distance with reduced peripheral blur and image swim for distance tasks. Larger, wider intermediate-vision area with improved binocularity. High, wide near zone for easy access with minimal eye movement; larger near vision area correctly positioned for a variety of reading tasks; 18mm minimum fitting height maximizes performance in large and small frames; Design by Prescription technology adjusts design by base curve and add power for consistent performance. Free form technology used to generate the back-surface progressive design incorporating enhanced optimization for the lenses in their as-worn positions for each individual Rx.
MINIMUM FITTING HEIGHT: 18mm
FITTING PROCEDURES: Measure monocular PD and fitting height
MATERIALS: 1.67 high-index, polycarbonate, hard resin and hard resin Transitions gray and brown. Also in SOLA’s Teflon EasyCare lens coating in all materials.
RX RANGE: -9.00 to +6.00D;
-12.00 to +8.00D (1.67 index). Add: 1.00 to 3.50 (hard resin and 1.67 index); 1.00 to 3.00 polycarbonate.
ORDERING: SOLA-authorized labs
|1.67 SUPER PROCEED INTERNAL PROGRESSIVE|
Barbara Martinez, optician with Britt Blackwell, OD, Rock Hill, S.C.: “It’s a top-of-the-line lens, one of the best progressives there is. It has a very wide corridor, so it’s good for reading. We use it for patients who need a high-index in combination with Transitions. We’ve had almost no non-adapts.”
Stuart Thomas, OD, Athens, Ga.: “I wear the lens and think it’s the absolute tops. It’s a very usable lens. The field of vision is especially good for the near prescription; the intermediate and distance are good too. I haven’t experienced any chromatic aberration. You don’t need any adjustment period.”
MANUFACTURER: Seiko Optical Products
FEATURES & BENEFITS: Patented technology invented in 1996 places the progressive surface on the back side of the lens for wider visual fields and total control of off-center astigmatism and power error; third-generation design; aspheric compensation for each sphere, cylinder, axis and add. Over two million optically precise Rx’s available. Two corridor lengths: 12mm and 14mm.
MINIMUM FITTING HEIGHT: 18mm (14mm corridor length); 16mm (12mm corridor length)
FITTING PROCEDURES: Additional measurements required for plus Rx; fitting cross and prism reference point at the optical center of the lens
MATERIALS: 1.67 high-index
RX RANGE: +6.00 to -10.00D, out to a -4.00 cyl (total power -10.00); Add: +0.50 to +3.50
ORDERING: Seiko-authorized labs