New wave of hydrophilic acrylic IOLs coming to United States

Long available in Europe, these biocompatible materials have been greatly improved and offer several clinical advantages, surgeons said.

Despite enjoying a decade of popularity elsewhere, hydrophilic acrylic IOLs have struggled to gain traction in the United States. Several early reports of calcification, although eventually resolved by lens manufacturers, soured the perception of the hydrophilic acrylic material in the U.S. market, leading to its dwindling presence here.

A survey of American Society of Cataract and Refractive Surgery members, for example, found that almost 70% of U.S. ophthalmologists in 2004 favored hydrophobic acrylic lenses.

Now, a new generation of hydrophilic acrylic IOLs is making its way through U.S. Food and Drug Administration trials and is expected to become available here soon.

Ocular Surgery News spoke with several ophthalmologists who predicted that U.S. surgeons, after some initial reluctance, will embrace the material because of its clinical advantages.

Uday Devgan

“It’s a biocompatible material and, in theory, it has less of an effect on the blood-aqueous barrier. The lens itself has the advantage of not being overly sticky,” OSN Cataract Surgery Section Member Uday Devgan, MD, FACS, said. “Hydrophobic acrylic tends to be sticky. It’s harder to perform a capsulotomy, more prone to YAG damage and sometimes they are not as pure and develop these ‘glistenings’ that we’ve seen in a lot of the current hydrophobics that are out there.”

Hydrophobic acrylic IOLs also have a higher refractive index, which can result in cases of dysphotopsia, he said.

“The hydrophilics have a lower refractive index and have less propensity toward dysphotopsia,” he said.

Dr. Devgan noted that hydrophobic lenses can be contraindicated in certain uveitic eyes.

“Some uveitis patients, when you put in traditional hydrophobic acrylics, develop these giant cells or clusters of inflammatory cells on the IOL optics. And that, of course, is bad for the patient’s vision,” he said.

Philippe Sourdille, MD, of Touzac, France, said hydrophilic acrylic lenses also carry more possibilities for innovation. The material is more easily folded for microincisional cataract surgery, can simultaneously function as a drug delivery device and holds more promise for pseudo accommodation, he said.

Ultimately, according to Dr. Devgan, the addition of hydrophilic acrylic lenses to the U.S. IOL market is beneficial simply because it expands the available options for treatment.

“It’s always a benefit to have more choices available to us. I think the majority of surgeons would be open and receptive to trying a new technology and having these in our toolbox of IOLs,” he said. “You want to avoid that situation where your only tool is a hammer, because then everything looks like a nail.”

Spotty history

Despite these advantages of hydrophilic acrylic, the U.S. market has been slow to adopt the material. This may be explained by several high-profile reports of late opacification that began to appear in the literature as the material gained widespread popularity internationally.

David J. Apple

OSN Cataract Surgery Section Member David J. Apple, MD, a renowned IOL pathophysiologist, tracked and studied the hydrophilic acrylic calcification problems over the past decade.

He said reports of decentration associated with the IOGEL (Alcon) were the first to give hydrophilic acrylics a “bad name” in the United States.

“[The IOGEL] was taken from the market, not because of the biomaterial, but because it was oversized and it could sometimes pop into vitreous after YAG laser,” he said. “Decentration gave [hydrophilic acrylic lenses] a bad name to start with before they had to change.”

The material itself later came under fire after Dr. Apple and colleagues learned of several cases of late opacification in the SC60B-OUV lens (MDR). In 2001, Dr. Apple and colleagues published an analysis of nine explanted SC60B-OUVs in which they found calcium deposits had permeated the entire lens and haptics. A few months later, researchers in Germany, examining another batch of explanted SC60B-OUVs, reported “the source of the opacification is a change in the IOL material itself.”

In 2003, the Aqua-Sense IOL (Ophthalmic Innovations International) also showed late postoperative calcification similar to that of the SC60B-OUV, Dr. Apple said.

Other reports of calcification surrounded Bausch & Lomb’s Hydroview lens, which was introduced outside the United States in 1995. The lens received FDA approval in 1999, but Bausch & Lomb delayed its U.S. release after receiving a few reports of late postoperative clouding and fogginess. The opacifications could not be cleared by Nd:YAG laser, and the IOL had to be explanted in some patients.

In 2001, researchers in Hong Kong found several surface opacifications on three explanted Hydroview IOLs, occurring an average of 1 to 2 years after surgery, composed of calcium, phosphorus and hydroxyapatite. Dr. Apple and colleagues came to a similar conclusion in a separate analysis.

Louis D. “Skip” Nichamin

Bausch & Lomb, through its own research, eventually learned the lenses had been contaminated by silicone deposits from a gasket added to the lens packaging in 1997. In 2001, the company introduced a new, silicone-free package and relaunched the Hydroview worldwide. The new packaging appeared to solve the problem, according to a 2003 white paper issue by the company. Bausch & Lomb eventually launched a new generation of anti-PCO square-edge acrylic lenses under the Meridian brand in the US in 2003.

OSN Cataract Surgery Section Member Louis D. “Skip” Nichamin, MD, clinical investigator for the Akreos AO, noted that Bausch & Lomb’s decision to pull support from the Hydroview lens may have stemmed more from the lens design than the material.

“It was somewhat antiquated in that it required a larger incision, it did not have an injector delivery device, and they were moving toward a one-piece design that was more amenable to increasingly smaller incisions,” he said.

Another setback

In 2000, another recall, this time of CIBA Vision’s MemoryLens, put the hydrophilic acrylic material back on the hot seat.

A year after buying the rights to the MemoryLens, the company recalled two models of the IOL after receiving reports of inflammation. CIBA Vision eventually traced the source to aluminum oxide used to polish the lenses during the manufacturing process. Six months later, the MemoryLens models were relaunched in U.S. and European markets.

Yet problems with these lenses persisted. In 2004, a report by Dr. Apple and colleagues appeared in Ophthalmology, in which they examined 106 explanted MemoryLens IOLs. Before explantation, all patients had decreased visual acuity at 2 years postop associated with a whitish fine granularity on the lenticular surface.

Dr. Apple and colleagues found calcium and phosphate within the surface deposits and postulated that a “special polishing technique” may have caused changes that led to calcification.

In 2004, CIBA Vision sold its entire surgical division to IOLTECH in France. In 2005, after discovering other problems with schisis and cavitation with the MemoryLens, Dr. Apple and colleagues called for the IOL’s removal from the market in a letter published in the Journal of Cataract & Refractive Surgery.

“After intensive examination of the cases with problems, we have come to believe that it is time to remove the MemoryLens from the market. It simply does not have the safety criteria necessary for long-term use,” they wrote. The MemoryLens is no longer sold.

Combined, the negative track records of these four IOLs had a profound effect on the FDA’s position on hydrophilic acrylic lenses, Dr. Devgan said. This may account for the slow approval process that future generations of IOLs have faced, he added.

“Because of the calcification reports, [the FDA] has been much more careful and more selective in their process of getting these IOLs approved for the United States. The FDA tends to err on the side of excessive safety,” he said.

Despite these early setbacks, hydrophilic acrylic lenses have continued to be a popular choice for surgeons practicing outside the United States. Because these lenses have all been implanted outside the United States, Dr. Apple said he has not yet been able to study them directly in his laboratory. These include two later generation IOLs, the Centerflex (Rayner) and Akreos (Bausch & Lomb).

“According to company reports, both of those lenses have been implanted hundreds of thousands, if not millions, of times, and nobody has reported primary calcification,” he said. Furthermore, Dr. Apple said he has not received any reports of explants of these IOLs.

“Trying to compare the old hydrophilic acrylics to the new generation of hydrophilic acrylics is like comparing new generation of silicone IOLs to old silicones IOLs, or comparing a the new-generation phaco machine to an old-generation phaco machine. Obviously, the technology only gets better and better,” Dr. Devgan said.

Coming to the United States

Several hydrophilic acrylic IOLs are currently in U.S. clinical trials and are slated to launch domestically within the next few years.

In early May, England-based Rayner Intraocular Lenses received pre-market approval from the FDA for the C-flex single-piece, ultraviolet-filtering hydrophilic acrylic IOL. The C-flex, which has been widely used internationally since receiving the CE mark in 2003, is the first of a new generation of hydrophilic acrylics to gain U.S. approval.

Rayner introduced what it calls the Amon-Apple Enhanced Square Edge, after identifying a need for a physical barrier to lens epithelial cell migration from the haptic surface to the adjacent optic.

“Sales of the lens are targeted to begin in September,” said Adrian W. Webber, Rayner’s director of sales and marketing. “A full launch is planned to coincide with the American Academy of Ophthalmology meeting in November in New Orleans.”

Other investigators are wrapping up a phase 2 trial of the Living Lens (EyeKon Medical), a single-piece hydrophilic acrylic IOL. Aside from an improvement in visual acuity in most patients, the investigators also noted a statistically significant drop in IOP, which they hypothesize was the result of better perfusion of the aqueous humor in and around the hydrophilic material.

“My patients have done extremely well. The visual acuities have been excellent,” Farrell C. Tyson, MD, who was a clinical investigator for the Living Lens, said. “It’s a one-piece lens, so it’s been centering and staying in the bag really well. And I have probably a less than 1% YAG rate because it has a square-edge design.

“What I’ve also liked about the lens is its flexibility. When you implant it into the eye, it unfolds at a much more rapid pace than a standard acrylic lens. If you’ve ever implanted a hydrophobic acrylic lens, it’s time-consuming to open up, and the haptics want to stick to the optic,” he said. “But the hydrophilic material opens up deliberately and at a good pace, so it’s almost similar to a silicone lens.”

The Living Lens is already CE-approved and has been implanted more than 300,000 times outside the United States, according to the company. EyeKon plans to submit a pre-market approval application to the FDA in late summer or early September.

Florida-based Lenstec has two hydrophilic acrylics in phase 3 trials — the Tetraflex lens, a single-piece accommodating IOL, and the Softec HD lens, an aspheric monofocal IOL.

The Tetraflex features a square-edge design for PCO reduction and is injectable through a 1.8-mm cartridge.

David C. Brown, MD, FACS, is a clinical investigator for the Tetraflex.

“The patients are absolutely giddy with their vision in terms of being able to read and also having excellent distance and intermediate vision,” he said. “Unusual surgical or common unpleasant visual side effects have not occurred, indicating that the lens will be friendly to both patient and surgeon.”

Speaking generally about the hydrophilic acrylic material, he said, “Until we have a nucleus of people here that can use it and start talking about the great results they get, no one’s tongue will be hanging out yet. But once it makes landfall here in the United States, I think it’s going to become a serious contender as the most popular lens material.”

Bausch & Lomb is also gearing up to launch the Akreos AO aspheric hydrophilic acrylic IOL within the United States. The lens is part of the company’s Akreos series, which has gained extensive popularity internationally, according to company officials.

The Akreos AO recently completed a successful phase 3 trial, and Bausch & Lomb is awaiting the FDA’s final determination.

The lens will be available in three diameters for three ranges of dioptric powers, Dr. Nichamin said. It is composed of a hydrophilic poly-HEMA/MMA copolymer that does not exhibit any propensity toward calcification or opacification, he said.

“But the overwhelming feature with this lens is the four closed-loop haptic design, which affords this implant a unique centering ability within the capsular bag,” he said.

Vigilance needed

As hydrophilic acrylic IOLs come back to the United States, Dr. Apple said he hopes that surgeons will remember that although there were many theories as to the cause of the original calcification reports, an answer was never found.

“Nobody really knows the answer. … We know the pathogenesis, we know how it occurs, but we don’t know the etiology, which is the basic cause,” he said.

He reminded surgeons to continue monitoring their patients for opacification, he said.

“All we can do is watch [the hydrophilics]. They tend to cause problems between 6 months and 2 years. I think any lens that claims to be clean, with no calcium, should be made to be watched for 2 years before they’re given a clean bill of health,” he said.

For more information:

• David J. Apple, MD, can be reached at the John A. Moran Eye Center, 65 N. Medical Drive, Salt Lake City, UT 84132; 801-213-2167; e-mail: djapple@comcast.net. Ocular Surgery News could not confirm whether Dr. Apple has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned.
• David C. Brown, MD, FACS, president and medical director of Eye Centers of Florida, can be reached at Eye Centers of Florida, 4101 Evans Ave., Fort Myers, FL 33901; 239-939-3456; fax: 239-939-1575; e-mail: david.brown@ecof.com. Ocular Surgery News could not confirm whether Dr. Brown has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned.
• Uday Devgan, MD, FACS, is in private practice in Los Angeles, chief of ophthalmology at Olive View-UCLA Medical Center and an assistant clinical professor at the Jules Stein Eye Institute at the University of California, Los Angeles. He can be reached at the Maloney Vision Institute, 19021 Wilshire Blvd. #900, Los Angeles, CA 90024; 310-208-3937; fax: 310-208-0169; e-mail: devgan@ucla.edu; Web site: www.maloneyvision.com. Dr. Devgan is a paid consultant for Bausch & Lomb and AMO and has received award monies from Alcon.
• Louis D. “Skip” Nichamin, MD, can be reached at Laurel Eye Clinic, 50 Waterford Pike, Brookville, PA 15825; 814-849-8344; fax: 814-849-7130; e-mail: nichamin@laureleye.com. Dr. Nichamin is a medical monitor for Bausch & Lomb.
• Philippe Sourdille, MD, can be reached at Le Chaigne, 16120 Touzac, France; 33-630-362-846; e-mail: philippe.sourdille@wanadoo.fr. Dr. Sourdille is a paid consultant for Cornéal Laboratoires.
• Farrell C. Tyson, MD, can be reached at 4120 Del Prado Blvd., Cape Coral, FL 33904; 239-542-2020; fax: 239-542-0704; e-mail: tysonfc@hotmail.com. Dr. Tyson does not have any financial interest in any products or companies mentioned.

• Bausch & Lomb Surgical Inc., maker of the Akreos AO IOL, can be reached at 180 Via Verde, San Dimas, CA 91773; 800-338-2020; fax: 800-362-7006; Web site: www.bausch.com.
• EyeKon Medical Inc., maker of the Living Lens IOL, can be reached at 2451 Enterprise Road, Clearwater, FL 33763; 800-633-9248; e-mail: info@eyekonmedical.com; Web site: www.eyekonmedical.com.
• Lenstec Inc., maker of the Tetraflex IOL and the Softec HD IOL, can be reached at 2870 Scherer Drive, Suite 300, St. Petersburg, FL 33716; 727-571-2272; fax: 727-571-1792; e-mail: lenstec@lenstec.com; Web site: www.lenstec.com.
• Rayner Intraocular Lenses Ltd., maker of the C-flex IOL, can be reached at Sackville Road 1&2, Hove, East Sussex, BN3 7AN, United Kingdom; 44-1273-205401; fax: 44-1273-324623; e-mail: iol_enquiries@rayner.com; Web site: www.rayner.com.

References:

• Apple DJ, Kleinmann G, Neuhann IM. Is it time to remove the MemoryLens IOL from the market? J Cataract Refract Surg. 2005;31:1681-1682.
• Neuhann IM, Werner L, et al. Late postoperative opacification of a hydrophilic acrylic (hydrogel) intraocular lens: A clinicopathological analysis of 106 explants. Ophthalmology. 2004;111:2094-2101.

• Andy Moskowitz is an OSN Staff Writer who covers all aspects of ophthalmology.