Advances in PALs boast less distortion, more individualized lenses lenses

Issue: March 2000

Since the advent of progressive-addition lenses (PALs), the technology has consistently improved to make them more patient-friendly than ever. Today, most practitioners boast more than a 95% success rate with this type of lens. In contrast, fewer and fewer dispensaries are prescribing bifocal and trifocal lenses as current and emerging presbyopes are fitted for progressives.

Companies such as American Optical (AO) Lens Company, Rodenstock, and Essilor of America, Inc. are all promoting new and enhanced additions to their current PAL collections. “I think everyone’s trying to increase the width of the intermediate/near zone without creating too much peripheral distortion,” said Mark Boas, OD, in private practice in Exton, Pa. “The objective is to widen those zones but not have so much induced astigmatism in the outer/lower portion of the lenses. To do that, and to be in a compact design, would be the best of both worlds.”

Less peripheral distortion

The newest progressive lens by Essilor is the Varilux Panamic, which utilizes “Global Design Management.” Several features are added to balance its surface, similar to a single-vision lens. Each lens has a symmetric multidesign; a regular power profile, even in the periphery; low and controlled astigmatism; and a high near vision with a short progression length.

According to Essilor, patients in clinical trials experienced faster visual detection and recognition in the periphery, truer peripheral vision, a wider field of vision at all distances, reduction in “swimming” and wider acuity fields. The lens was launched March 1.

A smooth transition into the near zone helps in patient adaptation, said Varilux Comfort lens advocate and new Panamic wearer Robert Davis, OD, in group practice in Pemberton Pines, Fla. “With the Comfort lens, my patients enjoy a nice wide distance area, they get very little swim or distorted vision out in the periphery, and they have a nice transition into the near zone,” he said. “The biggest advantage in my practice is that patients adapt very easily to it, more easily than the other no-line progressives that we’ve used. For myself, the Panamic gives me a wider field of view, and the visual acuity — especially at night — seems sharper with this lens.”

PAL for small frames

Debby Corriveau, marketing manager for AO Lens, said that the company will soon be launching AO Compact in three new high-index materials – the AO Compact 16, AO Compact 55, and AO Compact Rugged Fashionwear. The AO Compact is the company’s top progressive lens specifically designed for today’s popular smaller frames, said Ms. Corriveau. “We did not take the traditional longer corridor progressive and just shrink the corridor,” she told Primary Care Optometry News. “If you do that, you end up with large amounts of unwanted astigmatism. It is a new design that was engineered specifically to fit into the smaller fashion frames. It is a multidesign to ensure quality in all powers, which means that the actual design of the lens changes with add powers to ensure the stability.”

Dr. Boas said he has had success in prescribing the AO Compact for the last 2 years. “We recommend it, and as far as I can tell, my success rate is every bit as good as it used to be with the larger frame sizes,” he said. “The Compact solves problems of using small frames. It is a really nice design for general use.”

‘Specialty’ lenses

For higher prescription presbyopes, Dr. Boas said that he opts for the Tegra Outlook to keep the lens relatively thin. For frequent computer users who require a lens with a greater intermediate zone, he suggested the AO Technica. “We have quite a number of patients in that lens, and it was a very big problem solver for them,” he said. “They wanted to see the computer screen clearly, but also be able to see at a distance. They set aside that occupational spectacle when they go to lunch or go home for the night and put on their AO Compact in the nice small frame, which is fashionable right now.”

The size of the monitor with which the patient is working also plays a role in what type of lens to choose, said Dennis Magarahan, optician at Dr. Boas’ practice. “Figure out how many hours a day patients spend on the computer,” he said. “If they’re on 8 hours a day, especially as the screens get bigger – 17-, 19-inch monitors — that’s when they start looking for special glasses.”

Personalized progressives

While progressive lenses have come a long way, meeting the individual needs of each patient poses a challenge. A January Rodenstock press release states that “A new generation of lenses has to break away from the rigid, inflexible principle of progressive front surfaces and must meet the personal needs of the wearer. The atoric back surface and the progressive front surface are merged into one common surface which includes all the important individual parameters. That is, the aspheric, or atoric, back surface is now also combined with the progressive corridor.” The company utilizes the “Individual Lens Technology” process, which combines the calculation of the total lens based on the individual case (online optimization) and the flexible surfacing of the lens.

The company’s newest progressive lenses, the Life C and Life 2, are said to feature full asphericity and position of wear design as well as horizontal and vertical symmetry. This results in a soft design, wide viewing fields and a reduction in swim. A computerized mathematical formula is used to individualize the lens as well as a more balanced positioning of vision zones. The lenses, which will be available in a variety of Rodenstock styles and colors, will be launched at Optica 2000 in Cologne, Germany next month.

The Multigressiv 2, the company’s current progressive lens released in January 1999, is the top choice for Joel Halpern, OD, in private group practice in Dover, Del. “That’s our premier product,” he said. “It’s my top-of-the-line progressive. Rodenstock has come out with a lot of different index refractions, changed the colormatics on it and perfected the lens a little bit more. For patients who have a lot of astigmatism, where they’d be more prone to distortions, I use the Multigressiv.”

The future of progressives

Dr. Davis said that a wider intermediate zone would be an area of improvement for the future progressive lens. Measuring the lens when fitting a patient helps in the success rate as well, he noted. “The future is very bright, but the United States is lagging behind France and the rest of Europe,” he said. “I think it takes a little bit of special training and expertise to measure the lenses correctly for patients, but if eye care practitioners take enough time to do it right, they’re going to have very happy patients.”

As newer lenses are introduced into the market, said Dr. Halpern, more goals are met in the progressive arena, and it is more likely that bifocal lenses will be edged out completely. “The lens that comes out with absolutely no distortions – and that’s what you’re finding with these aspheric back-designs – will be the lens that’s going to make your lined bifocals totally obsolete,” he said.

For Your Information:

Mark Boas, OD, is in private practice. He and optician Dennis Magarahan may be reached at 577 West Uwchlan Ave., Exton, PA 19341; (610) 363-2303; fax: (610) 363-8560; e-mail: msboas@ccconnect.com. Neither Dr. Boas nor Mr. Magarahan has a direct financial interest in the products mentioned in this article, nor is either a paid consultant for any companies mentioned.

Robert Davis, OD, is in private group practice and a member of the team of optometrists for the Miami Dolphins. He may be reached at the Eye Center of Drs. Davis and Morris, 1732 University Drive, Pemberton Pines, FL 33024; (954) 432-7711; fax: (954) 432-8017. Dr. Davis has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

Debby Corriveau, marketing manager for American Optical Lens Co., may be reached at 50 Optical Dr., Southbridge, MA 01550; (508) 764-5024; fax: (508) 764-5010.

Joel Halpern, OD, is a member of the Block Vision Board, a Johnson & Johnson investigator for new products and a member of the Rodenstock USA Inc. Circle. He can be reached at Halpern Eye Associates, 885 S. Governor’s Ave., Dover, DE 19904; (302) 734-5861; fax: (302) 734-1921. Dr. Halpern has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.