Reasons for choosing an IOL as numerous as options

Design, material, biocompatibility and ease of use are all important features in decision-making.

As the selection of available IOLs continues to expand, choosing a foldable lens can be a complex task for a cataract surgeon. Many factors go into the decision. Posterior capsular opacification remains a concern, even with the latest generation of sharp-edged lenses. The performance of an IOL’s injection system can be a critical factor. Design, material, biocompatibility and ease of use are all important features in decision-making.

For our Spotlight on Intraocular Lenses in this issue, Ocular Surgery News talked with several experts in the field about the lenses they choose and the reasons they choose them. Their comments may be helpful in your own ongoing decisions on IOL choice.

SoFlex LI61U

Louis D. Nichamin, MD, said he uses many different implants, tailoring his choice to the patient’s characteristics and individual needs. He said he uses Bausch & Lomb’s SoFlex LI61U most often.

The SoFlex LI61U is a third-generation three-piece silicone IOL with a non-truncated optic edge. The lens is injected into the eye using the Mport single-handed disposable injector delivery system.

“The lens performs very well optically. I like silicone because it fits through a smaller incision in general because of its compressible elastic properties. This particular material is very slow to release. It doesn’t pop open like other silicone implants. I’m also very fond of the Mport injector system,” Dr. Nichamin said.

“I tend not to use inserting forceps anymore. I certainly prefer injectors,” he continued. “Typically [the inserter] passes through a smaller incision and allows for cleaner insertion because the implant does not come into contact with external surfaces, which potentially decreases the incidence of infection.”

In addition to a decreased risk of infection, injectors also provide the benefit of efficiency and speed. According to Dr. Nichamin, most injector systems are relatively easy to load. “My assistant does that, so I don’t have to look away or perform any additional folding and loading steps,” he said.

“Historically, a lot of the injectors ... could traumatize the implants,” Dr. Nichamin said. “Both the injectors and the latest generation of implants are designed for much safer and more reproducible delivery of IOLs.”

The Mport is a polypropylene syringe-style injector system that compresses the IOL into an M shape. Dr. Nichamin said using a particular injection delivery system with other lenses is not recommended by the manufacturers. However, it is possible and some surgeons do it on occasion.

“I have done it, but I typically do not recommend it,” Dr. Nichamin said. “One injector is specifically designed for one implant. But there is some crossover that takes place.”

Dr. Nichamin said there are not many cases in which he would still use forceps to insert an IOL.

“I do use the Bausch & Lomb Hydroview IOL on occasion, which does not have a dedicated injector delivery device. Otherwise, even in the setting of a complication, a broken posterior capsule for example, one can release an implant from an injector with significant control. The single-piece Alcon SA60 is particularly well-suited for this situation,” he said.

The SoFlex LI61U has a non-truncated optic edge. Dr. Nichamin said lenses with this feature may exhibit a slightly higher incidence of PCO than models with squared edges, but the incidence is “acceptably low for me.”

“Surgical technique must also be stressed. With very good cortical cleanup and capsular polishing, a lens like the LI61U delivers a very low rate of PCO,” he said.

“Second and third generation silicone is significantly different from first generation silicone, particularly the first generation silicone that was used with a plate-haptic design. Those implants showed much higher fibrosis, phimosis and PCO,” he continued. “With the latest generation of three-piece silicone implants, we’re seeing a very acceptable rate of PCO.”

“Increasingly, we will see that most IOLs, including silicone lenses such as the CeeOn 911A from Pharmacia, will now have truncated or squared-off optic edges that significantly reduce PCO,” he said.

Dr. Nichamin said the downside to using an IOL with a truncated edge is that there is some increase in unwanted optical images.

OptiEdge

John Hunkeler, MD, said he prefers posterior chamber lens implants with the OptiEdge hybrid edge design, manufactured by AMO. The OptiEdge design is available in both acrylic (Sensar with OptiEdge) and silicone (Clariflex) IOLs.

These lenses are designed with a sharp posterior optic edge to take advantage of the PCO inhibition caused by sharp optic edges and with a rounded anterior optic edge to minimize the unwanted optical images mentioned by Dr. Nichamin. IOLs with the OptiEdge design have a three-piece construction with acrylic or silicone optics and angled PMMA haptics.

“The OptiEdge IOLs, with their angled haptics, center well in the capsular bag and achieve early a stable refraction that I have predicted from preoperative calculation. I think the angular design offers an advantage over a planar lens,” Dr. Hunkeler said.

He said planar lenses have the potential to misalign in the anteroposterior axis of the eye, which can lead to spherical refractive errors.

The lenses are inserted using AMO’s Unfolder cartridge injector system. Minimal stretching occurs during the IOL implantation. Dr. Hunkeler said this allows him to insert the implant through a 2.8-mm to 3-mm incision after phaco, which measures 3.1 mm after IOL insertion.

“My preference is that the implant be handled by forceps minimally,” he said. “With the Unfolder cartridge system, the implant can be grasped and placed in the cartridge with minimal or no contact with the refractive optical surface and no manipulation of the haptics during the loading and insertion. When using folding forceps or handling the optics with forceps, meticulous attention must be paid to the cleanliness of the forceps surface. After autoclaving, material may dry on the surface of the lens. Further manipulation or holding the optic while placing it in other insertion devices can lead to significant damage to the optical integrity of the refractive surface. Manufacturers provide the surgeon with a clean, smooth, polished surface, and damaging such a surface cosmetically looks bad and undoubtedly reduces the quality of the optics.”

Dr. Hunkeler said he would like to see further improvements in injector systems. Rather than having the surgeon load the IOL into the cartridge before injecting the IOL, he said he would like to see the IOL arrive in the injector cartridge. He would also like to use a push system, similar to injection with a syringe, rather than a threaded system to inject the lens.

“It will be smoother and faster. It would be more fluent and user-friendly,” he said.

He said either the silicone or acrylic version of the IOL with the hybrid-edged OptiEdge is a good choice. He chooses between the models based on patient characteristics.

“I think the most important thing is to reduce capsular opacification. I think the overriding driver in that is having a squared off, sharp posterior edge. These implants offer that at a full 360°, so you have a square edge all the way around. I think that is a significant advantage in decreasing the likelihood of clouding of the capsule,” Dr. Hunkeler said.

He said he has used IOLs with OptiEdge in more than 400 patients and has not had any problems with decentration or PCO.

“I may have had to YAG one patient,” he said.

AcrySof acrylic

Robert Lehmann, MD, a cataract surgeon in private practice in Nacogdoches, Texas, and an investigator in the Food and Drug Administration trials that evaluated the Alcon AcrySof single-piece IOL, said the AcrySof is his lens of choice.

Dr. Lehmann said the AcrySof material is more biocompatible than any other lens he has used.

“I think I get better short-term results and a reduced incidence of cystoid macular edema. And I find that I need to use topical steroids for a shorter duration than I did while implanting PMMA or silicone lenses,” Dr. Lehmann said. “Plus, postop visits are reduced. When the patient’s second eye is done, they are pretty much dismissed for 1 year.”

Dr. Lehmann said he has had experience with many other lenses, but his YAG rate was always significantly higher with those lenses than now with the AcrySof.

He said the Monarch II injector, which allows the lens to pass through a 2.7-mm incision, is another reason he favors the AcrySof single-piece.

“When I used the MA-30 and the MA-60, I would prefer to fold the lens and implant it with the Burrato implantation forceps (ASICO). But with the single-piece lens and the Monarch II cartridge, I became an injector guy,” he said. “Before then I really preferred a manual implantation with forceps.”

Dr. Lehmann said earlier cartridges designed for injection of silicone lenses were not always reliable. He said cartridges would sometimes split, and occasionally a silicone lens would be inserted with a torn haptic.

“I just preferred manual folding with the earlier lenses. I chose to fold in the 3 o’clock to 9 o’clock position so that both loops would unfold in the capsular bag. It was very easy for me. The lens didn’t require any additional manipulation. Once you released it, both loops were there and it was home,” Dr. Lehmann said.

“With the Monarch II system, I had a cartridge and an injector that I felt was reliable each and every time. There were no surprises. The lens passed through the system easily and was never damaged,” he said. “The single-piece haptics on the AcrySof are virtually indestructible.”

Dr. Lehmann said there are few instances in which he would revert back to a manual implantation with forceps.

“If there is a compromised posterior capsule, if it can be converted to a round posterior rhexis, or if it happens to be a small central opening in the posterior capsule, in those instances I would still inject the single-piece lens. But if I have a longitudinal or radial posterior capsular tear, I think it’s smarter to implant the MA-60, perhaps with the loops in the sulcus and optic capture for greater stability,” he said.

Dr. Lehmann said the older silicone lenses, even with injectors to provide a controlled delivery system, still had more kinetic energy than the acrylic lens.

He said acrylic lenses routinely unfold over a period of 3 to 5 seconds in a gentle, controlled manner.

Paul Ernest, MD, who was also an investigator in the FDA study, said he prefers the AcrySof single-piece over silicone or PMMA lenses.

“I like the square edge for PCO issues. I like the way it has a knee-type hinge so that you don’t have tension on the capsular bag, and at the same time it centers beautifully. The capsule will shrink-wrap around the haptics, keeping it in place,” he said.

Dr. Ernest also cited the Monarch II delivery system as an advantage in using the AcrySof, noting that it allows the lens to pass through an unenlarged 2.7 mm incision.

Dr. Ernest said there are some complicated cases in which he would not use the single-piece AcrySof, such as a ruptured posterior capsule.

“Then I would use a multi-piece acrylic lens with 13-mm haptics, such as the MA-60 three-piece acrylic lens (Alcon), to basically do a sulcus fixation and trap the optic behind the capsulorrhexis so the lens remains centered. There’s no pigmentary dispersion from rubbing against the back of the iris. There’s also no myopic shift,” he said.

Dr. Ernest said the three-piece lens can be injected even in complicated cases, but in such cases he prefers to use Ernest-McDonald forceps (Katena Instruments).

Dr. Ernest said he does not use the injector in these cases because he does not want to take risk of having the handle distort the haptic. “And I’m also very comfortable using forceps because I have put in so many thousands in the past with forceps,” he said.

“But I love the Monarch II injector when it comes to the single-piece. I think it’s the only way to insert that particular lens,” he said.

Dr. Ernest also noted Alcon’s recent modification of the AcrySof design, a lens edge with a textured design to decrease the possibilities of unwanted photic phenomena.

AcrySof Natural

Dr. Ernest was also part of a study evaluating the AcrySof Natural, a new version of the AcrySof that has a covalently bonded yellow chromophore added to the material. The AcrySof Natural is currently awaiting FDA approval.

“It’s not a coating. Some of the older types of lenses that had this type of applied chromophore had it done as a coating, which wore off. The new yellow chromophore is now part of the AcrySof material,” Dr. Ernest said.

“What we are trying to do is cut down on the blue light transmission without affecting the color perception on the part of the patient,” Dr. Ernest explained.

Dr. Ernest said that there is evidence that blue light may play a role in damaging the retinal pigment epithelium. “There are molecules in the retinal pigment epithelium that absorb blue light as we grow older, which causes free radicals to form,” he said. “This in turn will damage the retinal pigment epithelium. If we can have something that is filtering out a considerable amount of the blue light, this will help the process. We can’t say that this will prevent macular changes. But we do have science out there that tells us blue light plays a role in damage to the retinal pigment epithelium.”

He said researchers developing the lens have shown through light transmission curves that the new lens allows amounts of blue light transmission very similar those of the crystalline lens of a healthy 50-year-old adult who does not have a cataract.

“We’ve also done color tests and contrast sensitivities that show there is no difference between the lens with the chromophore and the implant without the chromophore,” Dr. Ernest said.

“All implants today have an [ultraviolet] absorber built into the plastic, but it only filters out wavelengths of 400 nm and below. It doesn’t filter anything out above 400 nm. The human lens filters out a considerable amount of the rays between 400 nm and 500 nm, anywhere from 40% to 80%. This lens should mimic that,” he said.

Dr. Lehmann said the AcrySof Natural should be particularly important when implanting an IOL in patients already beginning to develop macular degeneration.

“I can’t think of a downside to it,” he said. “We know that it does not alter or disturb color perception.”

CV232 SRE

CIBA Vision has recently launched its own take on a square-edged IOL, the CV232 SRE — a square-round-edge IOL.

The CV232 SRE received FDA approval at the end of May. Ocular Surgery News was unable to contact a U.S. surgeon with experience using the lens because the product has not yet been distributed here.

According to the company, the posterior square edge of the lens facilitates 360° capsular contact, which may improve postoperative results. The CV232 SRE also has a rounded anterior edge, which potentially minimizes glare and photic phenomena.

According to the company, European surgeons have observed the 360° capsular contact and have not noted any complaints of glare or other dysphotopsias from their patients. The multipolymer acrylic material is highly biocompatible and exhibits low rates of bacterial adhesion and protein absorption.

According to a company press release, the CV232 SRE does not require a folder or injector. The prerolled lens gradually unfolds and centers itself once inserted in the capsular bag. This atraumatic implantation reduces the possibility of damage to ocular tissues, and the prerolled configuration allows for easy viscoelastic removal.

Collamer lens

Stephen Bylsma, MD, said he prefers the Collamer plate-haptic IOL manufactured by STAAR Surgical.

“The lens is very easy to insert. I started using it during the FDA study prior to its approval and was really impressed with how these patients did,” Dr. Bylsma said.

According to Dr. Bylsma, the Collamer plate-haptic lens is injected using a standard STAAR Microstaar Injector, which uses a foam tip plunger to easily push the lens through a 2.7 mm incision.

Dr. Bylsma noted the benefits of using injectors include the avoidance of contact with the conjunctiva, which may reduce the likelihood of infection; the use of smaller incisions than possible with forceps; and a controlled entry.

“It’s the most atraumatic, controlled, aseptic or sterile method to place a large-optic IOL through a very small incision,” Dr. Bylsma said.

Dr. Bylsma uses the injector for lens insertion in all cases. However, he said the plate-haptic lenses should not be used when there is a tear in the posterior capsule.

“I have used the Collamer lens in the presence of an anterior capsular tear in the capsulorrhexis, and those patients did fine. But the lens has to be oriented at 90° to the tear,” Dr. Bylsma said.

Dr. Bylsma noted the lens is not FDA approved for this indication, and he said it is better not to place a plate-haptic IOL when there is any kind of compromised capsule.

“If there is a tear in the anterior capsule, and certainly any kind of compromised posterior capsule, I would go to a three-piece lens,” Dr. Bylsma said.

Dr. Bylsma noted that there is a higher PCO rate with the Collamer IOL compared to square-edged lenses.

“That is a concern,” he said. “However, I am comfortable with YAG capsulotomy. YAG capsulotomy is easy to perform with the Collamer plate-haptic IOL because the material doesn’t ding.”

Dr. Bylsma explained the Collamer material is highly hydrated so that laser energy defocuses into the lens rather than permanently damaging the material.

“It simply displaces the water, and then the water diffuses back. The ding that you initially see is usually gone within 5 to 10 minutes,” Dr. Bylsma said.

“For me, the Collamer goes through the smallest incision and is the most atraumatic with the biggest optic. So the tradeoff in the capsulotomy rate is worth it,” Dr. Bylsma said.

The Collamer lens is available in a 6.3-mm optic, which Dr. Bylsma said he can place through a 2.5-mm incision without a problem. According to Dr. Bylsma, this is significant because larger optics have less edge glare and decentration.

“If the optic is bigger, then you have a bigger ‘sweet spot.’ If it decenters slightly, you are not going to get the edge of the lens in the visual axis,” he said.

Dr. Bylsma said he has not seen problems with decentration using the Collamer plate-haptic lens. He said this is not a problem with most of the lenses currently available.

“We do know that many of the square-edged optics have the side effect of dysphotopsia, where there are bright or dark visual phenomena. The smaller the optic, the more likely this is to happen because this is an edge effect. But most of the lenses today are really terrific,” Dr. Bylsma said.

Toric IOL

If a patient has more than 1.2 D of corneal astigmatism, Dr. Bylsma said he uses a Toric IOL, also manufactured by STAAR Surgical.

“Certainly for me it’s the most reliable way to correct astigmatism optically rather than with tissue manipulation using limbal relaxing incisions,” Dr. Bylsma said.

According to Dr. Bylsma, one of the main concerns in using the Toric IOL is rotational stability. He said rotational stability is important because appropriate correction of the patient’s astigmatism is lost when the lens rotates off axis.

However, Dr. Bylsma said recent work has shown rotational stability of the Toric lens is improved by inserting the toric surface of the lens towards the posterior capsule, “flipping it over so it is in the opposite direction of what was intended.”

Dr. Bylsma said that there is no real trick to flipping the lens. “It’s all in the loading. Just take the lens out of the package and instead of putting it directly in the cartridge right away, turn it over. It couldn’t be simpler,” he said.

Dr. Bylsma said the results achieved in flipping the lens have been very good, with about 85% of patients achieving 20/40 or better with the lens flipped as opposed to 50% of patients without flipping.

“This is one of only two new-technology IOLs designated by the federal government for a higher reimbursement rate,” he said. “So there must be something about it, and there is. It’s been proven and fully FDA approved to reduce astigmatism. It’s the only lens available to address astigmatism and not just the spherical component of the patient’s refraction.”

For Your Information:

• Louis D. Nichamin, MD, can be reached at the Laurel Eye Clinic, 50 Waterford Pike, Brookville, PA 15825; (814) 849-8344; fax: (814) 849-7130; e-mail: nichamin@laureleye.com. Dr. Nichamin has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• John D. Hunkeler, MD, can be reached at the Hunkeler Eye Center, 4321 Washington, Suite 6000, Kansas City, MO 64111; (816) 931-4733; fax: (816) 931-9498; Web site: www.hunkeler.com. Dr. Hunkeler has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
• Robert Lehmann, MD, can be reached at 5300 North Street, Nacogdoches, TX 75961, (936) 569-8278; fax: (936) 569-0275; e-mail: lehmann@cox-internet.com. Ocular Surgery News was unable to confirm whether Dr. Lehmann has a direct financial interest in the products mentioned in this article, or whether he is a paid consultant for any companies mentioned.
• Paul Ernest, MD, can be reached at TLC Eye Care Center of Michigan, 1116 W. Ganson St., Jackson, MI 49202; (517) 782-9436; fax: (517) 782-3001. Dr. Ernest is a paid consultant for Alcon. He has no direct financial interest in any products mentioned in this article.
• Stephen Bylsma, MD, can be reached at 1414 E. Main St., Santa Maria, CA 93454; (805) 925-2637; fax: (805) 347-0033. Ocular Surgery News was unable to confirm whether Dr. Bylsma has a direct financial interest in the products mentioned in this article, or whether he is a paid consultant for any companies mentioned.

• Bausch & Lomb, makers of the SoFlex LI61U and Hydroview IOLs, can be reached at 180 Via Verde Drive, San Dimas, CA 91773; (800) 423-1871; fax: (909) 971-5124.
• AMO, makers of the Sensar and Clariflex IOLs, can be reached at 2525 Dupont Drive, Irvine, CA 92612; (800) 433-8871; fax: (714) 246-5913; Web site: www.allergan.com.
• Alcon, makers of the AcrySof, can be reached at 6201 South Freeway, Fort Worth, TX 76134; (817) 293-0450; fax: (817) 568-6142.
• CIBA Vision, makers of the CV232 Square-Round-Edge IOL, can be reached at 11460 Johns Creek Parkway, Duluth, GA 30097; (678) 415-3711; fax: (678) 415-2320.
• STAAR Surgical, manufacturer of the Collamer IOL and the Toric IOL, can be reached at 1911 Walker Ave., Monrovia, CA 91016; (818) 303-7902; fax: (818) 358-9187.