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Improvements in soft toric contact lenses include new materials, range extensions
Recent developments increase the number of patients who can be helped by toric contacts, according to manufacturers and practitioners.
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Virtually every major contact lens manufacturer has either recently introduced improvements or expansions in their toric soft contact lens product lines or has plans to do so. Manufacturers and clinicians say the new lens models offer improved materials, extended ranges and innovative designs to suit the needs of a larger number of astigmatic patients.
“There’s a whole new wave coming in the better materials,” said H. Dwight Cavanagh, MD, PhD. “The designs and fitting of the new materials are different from the old ones. [Practitioners] might have to go back and do a little homework on them because they are a little different now.”
One of the recent advances is the availability of toric lens models made with silicone-hydrogel lens material. This hyper-oxygen-permeable material allows oxygen transmission rates that are up to five times that of traditional materials, Dr. Cavanagh said.
“Until now, all torics were made out of conventional materials that allowed low oxygen transfer rates. It’s like comparing DVD to videotapes. [The older materials are] passé technology now,” he said.
Charles B. Slonim, MD, said, “The designs are essentially getting better and the companies are starting to use materials that have been known to perform excellent in the spherical world, and now they’re becoming available in toric lenses. Fitting and reproducibility is just excellent. A lot of lenses can now be fit almost directly from the refraction.”
Keys to fitting torics
A 2003 survey by Health Products Research found that there are 26 million Americans who wear contact lenses. More than 10 million of those wearers are astigmatic, according to the survey. The new toric models will increase the number of astigmatic patients who can benefit from contact lenses, Dr. Slonim said.
“Some are told they cannot wear contact lenses because they have astigmatism,” he said. “Someone lost a patient there, and we’re happy to pick them up. We’re happy because we know we can fit them.”
Fitting the new torics is straightforward, Dr. Slonim said. The axis of cylinder can be prescribed the same as it would be for glasses now, he explained, because the lenses are better designed to remain stable.
“Because of the perceived notion that toric lenses are more difficult to fit and more time-consuming, all of these things from the past have essentially made [practitioners] shy away,” Dr. Slonim said. “Now with the ease with which they are fit, the chair time is less and they’re less expensive, so patients are more likely to utilize them.”
Fitting is based on the corneal curvature, and most companies offer two or three base curves, Dr. Slonim said.
The lens power should be as close to the phoropter-measured sphere as possible, he explained. The cylinder measurement and the axis measurement should also be as close as possible.
“Typically a toric lens will mask 0.75 D of cylinder on its own, so you don’t need to choose a cylinder greater and rarely choose one that is identical,” he said. “Try to go one-fourth or one-half less because you will get a masking effect from the contact lens itself.”
Dr. Slonim suggested stocking trial lens sets from two or three companies. “A small number of lenses can fit so many people,” he said.
Most of the newer toric lenses are specially designed to stabilize after a few blinks, Dr. Slonim said.
“You used to have to wait 20 minutes for a [toric] lens to stabilize,” he said. “Nowadays, after a few blinks and maybe a drop of lubricant, the lens sits where it’s going to sit. The designs are now so reliable and the stability of the lenses is so much better that it doesn’t take a lot of chair time to fit.”
Bausch & Lomb, CIBA Vision, CooperVision and Vistakon all have recent developments or improvements in their toric contact lens lines.
Bausch & Lomb
Bausch & Lomb spokesman Tor Constantino said the company’s SofLens 66 toric is the most often fit toric lens in the industry, and the launch of the toric version of its PureVision lens is expected this summer.
The SofLens 66 toric is available in sphere powers of +6 D to –9 D, with cylinder powers of –0.75 D, –1.25 D, –1.75 D, –2.25 D and –2.75 D at axes from 0° to 180° in increments of 10°.
The PureVision lens is made with silicone-hydrogel material that allows increased oxygen transmissibility to the eye, according to the company. Proprietary technology changes the surface of the lens to resist protein deposits. The PureVision’s aspheric anterior surface reduces spherical aberrations, company materials said.
“It all gets down to corneal swelling. Are you allowing enough oxygen to get to the eye?” Mr. Constantino asked. “The Pure Vision toric lens is clinically shown to have no more or less corneal swelling than sleeping without a lens.”
The PureVision will be available in sphere powers of –0.25 D to –6 D, with cylinder of –0.75 D, –1.25 D and –1.75 D at axes of 10° to 180° in increments of 10°.
A multifocal PureVision lens is expected to be on the market later this year, Mr. Constantino said.
CIBA Vision
Ciba Vision already has its Focus Dailies Toric model, a disposable lens made of nelfilcon A. The range of that model has just been expanded.
“Not many practitioners are aware that it is available, and we just recently increased the power range available on this particular lens,” said Rick Weisbarth, OD, CIBA Vision vice president of professional services.
Sphere now ranges from +4 D to –8 D with cylinder of –0.75 available at axes of 90° and 180°.
“This has been a very popular lens,” he said. “It seems to meet needs of athletes, not to mention the general population.”
The lens has a double slab-off design, meaning it has a thin area at the top of the lens and another at the bottom. The lids grab onto those thin zones and hold the lens in place.
“This is the only daily disposable lens marketed,” Dr. Weisbarth said. “There is no other company who has a daily disposable toric lens.”
A second toric lens from CIBA Vision will be the O2Optics toric, a silicone hydrogel to be launched this summer. The company’s spherical O2Optics lens was launched last fall after receiving Food and Drug Administration approval for up to 6 nights of extended wear.
“The key advantage of this product is the tremendous oxygen transmissibility … that the material allows,” Dr. Weisbarth said.
He said the lens will have a prism ballast design, meaning that it will be shaped like a triangle. The thin part of the lens goes under the upper lid, and the thicker part is held in place by the lower lid.
The O2Optics toric will be a 1- to 2-week disposable lens.
CooperVision
CooperVision, which recently acquired Ocular Sciences Inc., introduced an extension to its Vertex Toric line last fall. The Vertex Toric XR, which stands for extended range, features cylinder measurements to accommodate a larger population of patients with astigmatism, according to a company press release.
The addition to CooperVision’s selection offers three new cylinder powers, –2.75 D, –3.25 D and –3.75 D, which are available on axes from 0° to 180° in 5° increments. The Vertex Toric XR has sphere powers ranging from +6 D to –8 D.
“The Vertex Toric offers practitioners a viable alternative for a twice-monthly replacement lens in the higher cylinder powers that traditionally have not been available prior to the launch of this lens,” said Richard Franz, OD, vice president of professional relations at CooperVision.
Both Ocular Sciences and CooperVision created technologies to improve manufacturing reproducibility so that these high cylinder lenses can be manufactured as disposables.
“Now we have the option of allowing patients to replace the lenses more frequently, which certainly makes it healthier and more convenient for the patient,” Dr. Franz said. “A lot of good information came out of developing this technology. It is cutting edge in terms of toric lenses.”
Vistakon
Vistakon, maker of the Acuvue 2, has two recent additions to its lens selection – an expansion of the range of the Acuvue Advance lens with Hydraclear and the introduction of Acuvue Advance for Astigmatism, which was launched in February. Hydraclear is the company’s brand name for proprietary technology that combines a wetting agent with base materials.
In March, the Advance lens with Hydraclear became available in powers of +8 D to –12 D. Powers were previously available to +4 D. The extended range will be available in 0.25 D steps to +6 D and then in 0.5 D steps to +8 D.
Vistakon’s newest lens, the Acuvue Advance for Astigmatism, is the company’s first toric lens to feature the Hydraclear technology. The lens features an accelerated stabilization design that stabilizes the lens in less than 60 seconds, according to Vistakon.
The Advance Astigmatism lens is available from 0 D to –6 D in 0.5 D steps in cylinder powers of –0.75 D and –1.25 D at axes from 90° and 180° in 20° increments, and in cylinder of –1.75 D at axes of 90° and 180° only.
“The doctors I work with have always considered toric fitting a mystical thing that I’m best at, and they would send their toric patients to me,” said Christian P. Guier, OD, an instructor in ophthalmology at the Mayo School of Medicine. “Now, this lens makes enough sense that if any of the ophthalmologists I work with had the time or interest in fitting it, they could fit this toric lens directly.”
In addition to stabilizing in less than 60 seconds, this toric lens is easy to fit, Dr. Guier said.
“This toric design demystifies toric fitting,” he said. “It allows a doctor to go in and use a fresh prescription and put a lens on based on that prescription and see near-immediate results.”
The Advance lenses offer class 1 UV protection, meaning they block 90% of UVA and 99% of UVB light, according to the company.
For Your Information:
- H. Dwight Cavanagh, MD, PhD, can be reached at 5323 Harry Hines Blvd., Dallas, TX 75390-9057; 214-648-8074; fax: 214-648-8074; e-mail: dwight.cavanagh@utsouthwestern.edu.
- Richard Franz, OD, can be reached at CooperVision, 370 Woodcliff Drive, Suite 200 Fairport, NY 14450.
- Christian P. Guier, OD, can be reached at 4500 San Pablo Road, Jacksonville, FL 32224; 904-953-7110; e-mail: guier.christian@mayo.edu.
- Charles B. Slonim, MD, can be reached at Older and Slonim Eyelid Institute, 4444 E. Fletcher Ave., #D, Tampa, FL 33613; 813-971-3846; fax: 813-977-2611.
- Rick Weisbarth, OD, can be reached at 11460 Johns Creek Parkway; Duluth, GA 30097; 678-415-3937.
- Bausch & Lomb can be reached at 8500 Hidden River Parkway, Tampa, FL 33637; 800-227-1427; Web site: www.bausch.com.
- CIBA Vision can be reached at 11460 Johns Creek Parkway, Duluth, GA 30097; 678-415-3937; Web site: www.cibavision.com.
- CooperVision can be reached at 370 Woodcliff Drive, Suite 200, Fairport, NY 14450; Web site: www.coopervision.com.
- Vistakon can be reached at Johnson & Johnson Vision Care Inc., 7500 Centurion Parkway, Suite 100, Mail Stop: D-CREL, Jacksonville, FL 32256; 800-843-2020; Web site: www.ecp.acuvue.com
- Daniele Cruz is an OSN Staff Writer who covers all aspects of ophthalmology.