The New IOL Landscape
Where quality of vision joins safety as a prime goal.
BY JOHN PARKINSON ASSOCIATE EDITOR

	ILLUSTRATION: JIREHDESIGN.COM

While biocompatibility continues to be a significant goal in the development of post-cataract IOLs, manufacturers have also been looking for ways to address patient quality-of-vision concerns. The latest generation of IOLs contains many specialty products that differentiate themselves through their capabilities.

Although this specialty trend can lead to many questions for ophthalmologists about what products do what, and which patients are best-suited for each lens, it also brings benefits. Surgeons have more choices for treating patients more effectively based on their individual vision needs.

Also, the quality of vision provided by today's post-cataract IOLs make many of them suitable for patient-paid refractive lens exchange as well. In this article, surgeons provide pearls for making the most of the lenses they're using today, and we look ahead to some of tomorrow's IOLs.

Alcon

AcrySof Natural. The AcrySof Natural single-piece IOL (SN60AT) is indicated for in-the-bag placement. Its optic diameter is 6 mm. In its diopter range of +6D to +30D, it is available in increments of 0.5D. In its diopter range of +31D to +40D, it comes in increments of 1D.

Richard Braunstein, M.D., chief of the division of anterior segment at Columbia University Medical Center in New York, implants this IOL into 98% to 99% of his patients. He sees the greatest benefit of this IOL stemming from its blue-light filtering, which may protect patients from AMD. "Patients appreciate a lens that could potentially reduce their risks of a blinding disease," says Dr. Braunstein.

	The AcrySof Natural filters light much like the human lens.
	The AcrySof HOA blocks blue light and has a posterior aspheric design.

Dr. Braunstein offered these pearls:

► The AcrySof Natural single-piece performs similarly to the traditional AcrySof IOLs.

► The IOL's yellow tint makes it easy for the surgery staff to visualize and therefore handle in the OR.

► Dr. Braunstein finds the lens suitable for all patients, including those who have implants in the fellow eye.

AcrySof HOA. The AcrySof HOA single-piece (SN60WF) is also for capsular bag placement. Its optic diameter is 6 mm. It's currently available from +16D to +26D in increments of 0.5 diopters, although a diopter expansion is pending.

Stephen Lane, M.D., clinical professor at University of Minnesota, and managing partner of St. Paul Minnesota-based Associated Eye Care, sees the greatest benefit to the patient in terms of fewer spherical aberrations. Dr. Lane is involved with a study where he is implanting the HOA in one eye of every patient who is getting bilateral implants and implanting the AcrySof Natural in the other eye. The only difference between this lens and the Natural is that the HOA has a posterior aspheric design. He estimates he has done 50 to 60 procedures thus far.

Dr. Lane's pearls include:

► He doesn't implant the lens in capsular instability cases.

► The handling characteristics of the AcrySof HOA are identical to those of all the other AcrySof single-piece IOLs. Therefore, implantation of the AcrySof HOA IOL should feel familiar to surgeons who have worked with the other single-piece AcrySof lenses.

► "This IOL increases widespread applicability to larger segments of the patient population allowing for a 'cure' of their refractive errors and improvement of their uncorrected visual acuity," Dr. Chu said.

Alcon is also working with the FDA towards the release of its pseudoaccommodative lens, AcrySof Restor. Results of Phase III clinical trials were reported earlier this year, and the company has submitted its pre-market application. Approval for the lens could come in 2005.

AMO

	Wavefront technology was utilized in creating the Tecnis.
	The Sensar can be loaded into the injector a few minutes prior to delivery.

Tecnis. The Tecnis is a posterior-chamber, 3-piece foldable IOL for capsular bag fixation. It's an aspheric, modified prolate lens made of a UV-absorbing polysiloxane. The Tecnis Z9000 is available from 5D to 10D 1-diopter increments, and from 10.5D to 30.0D in 0.5-diopter increments. Its haptic length is 12-mm. The Tecnis Z9001 comes in powers from 5D to 10.0D in 1-diopter increments and in powers from 10.5D to 30.0D in 0.5-diopter increments. Its haptic length is 13-mm.

Ralph Chu, M.D., medical director of Edina, Minnesota-based Chu Vision Institute, implants the Tecnis into 95% to 98% of his patients. According to Dr. Chu, the biggest benefit to the patient of this lens is the ability to reduce spherical aberrations, particularly in night driving situations.

Dr. Chu believes this creates a safety feature for the lens. "You can actually improve a patient's contrast sensitivity by 40%, where they can have better reactions to hazards on the road," states Dr. Chu.

Dr. Chu is referring to an FDA-monitored investigation that was a controlled, multicenter, intraindividual clinical study done with a traditional spherical acrylic lens and the Tecnis in simulated night driving tests. Results were significantly better for participants with the Tecnis than the other IOL. After the study, the FDA approved labeling claims that the lens reduces spherical aberrations.

Dr. Chu suggests these pearls:

► If the lens is placed in the sulcus, the optic should be captured in the posterior capsule to ensure good centration for full effect.

► The addition of a spherical lens through piggybacking to the Tecnis' aspheric surface causes very little loss of effect or benefit to the patients. For piggybacking applications, he suggests placing the Tecnis in the capsular bag and placing the other IOL in the sulcus.

► The Tecnis should not be used in patients who are post hyperopic LASIK or PRK for a correction +2 or greater. The combination of this corneal ablation pattern and the Tecnis IOL may result in a paradoxical increase in spherical aberration for patients.

Sensar. The Sensar with OptiEdge combines three design elements including: a rounded anterior edge, a sloping side edge, and a squared posterior edge. It is a three-piece IOL, and its material is acrylic/UV. The Sensar (AR40e) comes in powers from -10.0D to +27.5D in half-diopter increments and is also available from +28D to +30.0D in whole-diopter increments.

Colorado Springs, Colo.-based Steve Dewey, M.D., sees the greatest patient benefit as the IOL's ability to perform over time. "Patients are coming back to me 4 years after [the IOL implant], and they have a [posterior] capsule looking as clear as the day I did the surgery." The success of the IOL has prompted secondary surgery referrals to Dr. Dewey's Colorado Springs Health Partners practice. "Regardless of how innocuous we consider a YAG capsulotomy to be, I think most physicians underestimate the implications a patient may perceive."

Dr. Dewey implants 98% to 99% of his cataract patients with the Sensar. His pearls include:

► During the procedure, assistants and technicians can load the IOL sooner and let it sit for 3 to 4 minutes prior to delivery, thus allowing for a faster handoff when the surgeon is prepared for implementation.

► Storage of the IOLs and balanced salt solutions (BSS) in various room conditions can affect how fast or slow the Sensar will unfold upon insertion. In Dr. Dewey's office, the IOLs and BSS are kept in a cabinet that is adjacent to an outside wall. In the summer, the warmer temperature allows the Sensar to unfold rather quickly, and the converse is true in the winter.

"We're only talking about a couple of seconds either way, but it is important to let the haptics come to proper orientation as the optic unfolds before placing the trailing haptic in the bag."

► The Emerald Ease and the Emerald T injector systems (delivery systems for Sensar) have different delivery methods. With either system, the surgeon should make sure the lead haptic is in the proper orientation inside the transparent window, and that the trailing haptic will avoid the plunger tip. With the Emerald Ease, the surgeon can use one hand, but must use restraint as the IOL leaves the cartridge. When using the Emerald T, IOL implantation requires two hands but has a slow steady delivery.

Bausch & Lomb

	The SofPort AO is designed to be aberration-free.
	Users say the Meridian's design allows for superior centration.

SofPort AO. The SofPort AO is a foldable, silicone, aspheric IOL designed to be aberration-free so it will not contribute to patients' pre-existing higher-order aberrations.

The lens has PMMA modified C-loop haptics and square edges. It's 13 mm long and has a 6-mm asymmetrical biconvex optic with a refractive index of 1.43. The company says that the aspheric optics on both the anterior and posterior surfaces of the lens consistently direct light rays to an optimized focal point.

The SofPort AO will be available in powers from 0D to 4D in whole-diopter increments in February, and is available now from 5D to 30D in 0.5-diopter increments. It was designed for insertion through a sub-3-mm incision using B&L's SofPort System inserter, which is a single-use, single-handed planar delivery system that is totally disposable.

According to Louis D. "Skip" Nichamin, M.D., of Brookville, Pa., "The aspheric design of the SofPort AO optimizes image quality regardless of a patient's idiosyncratic spherical aberration or previous surgery. In addition, theoretical models and lab testing show that the image quality produced by this lens does not appear to be affected by decentration or tilt. While we are awaiting hard data to confirm that this IOL's optical performance is superior, it looks very promising."

Currently, Dr. Nichamin implants 85% to 90% of his cataract surgery patients with the IOL, but expects that percentage to increase because "This is a lens that can be used in just about every situation." He finds that from a handling standpoint, the new IOL is no different than B&L's standard spherical, square-edged optic model, the SofPort LI61SE.

Dr. Nichamin offers these pearls for the SofPort AO:

► The distal tip of the SofPort system's injector has two little slits on each side, which can get "hung up" when the surgeon is entering a wound that has a deep groove or a limbal relaxing incision. "I recommend using a lens hook or other instrument as a glide," Dr. Nichamin says. "I place the instrument into the wound first, press down, and then as if going over a shoehorn, insert the injector. That way it won't get caught on the bottom floor of a wound with a deep groove." (This is not an issue with standard, single-plane incisions.)

► "As you enter the eye and begin the injection, I recommend angling down and to the surgeon's right. That ensures delivery of the leading haptic underneath the anterior capsular leaflet and into the bag."

► Dr. Nichamin also says that, as with any injector, it's worth mentioning that attention needs to be paid to how the implant is loaded into the injector.

Meridian. The Meridian (HP60M) is a three-piece foldable, hydrophilic acrylic lens with broad blue PMMA haptics. The optic is biconvex and is 6.0 mm in diameter. Its power range is +10.0 to +30.0D in 0.5D increments.

Jay Lippman, M.D., principal of New Rochelle, N.Y.-based Lippman Eye Care Centers, and clinical professor of Ophthalmology at New York Medical College, uses the lens in approximately 60% of his cataract surgical patients. He sees superior biocompatibility and centration of the Meridian as the principal benefits to the patient.

"These eyes are very quiet postoperatively," observes Dr. Lippman. Specifically, he notes enhanced uveal tissue compatibility with the hydrophilic acrylic material, superb centration, and the ability of the lens' 360-degree posterior square edge to effectively retard the formation of posterior capsular opacification.

Dr. Lippman shares these pearls about the Meridian:

► "The Meridian exhibits superior centration because of the manner and the extent to which the optic is covalently bonded to the haptics. The haptics are attached entirely peripheral to the optic and create both a larger footprint in the capsular bag and an entirely unimpeded optical platform," states Dr. Lippman. "It's almost like having an endocapsular tension ring-like device in the eye. The bag is more effectively held open and lens centration ensues."

► The delivery technique requires some extra attention because no compatible injector is currently available. Dr. Lippman has used injectors for delivering the Meridian, but feels using injectors can cause stress fractures near the insertion of the haptic because the haptic is so broadly inserted. He suggests delivering the IOL bimanually using a vertical folding technique. "As you insert a second instrument it is helpful to keep the lens down in the bag away from the endothelium as it unfolds, and also to help you disengage from your folding forceps."

► Because of the lens' relatively large footprint and increased thickness, he prefers not to use the lens in powers of 25D or more in smaller eyes.

B&L is also working to introduce another hydrophilic acrylic IOL, the Akreos Adapt. European doctors have been implanting this lens for years, but it is just going into clinical trials in the U. S. When the Akreos is introduced into the U.S., it will be with an inserter that is compatible with sub-3-mm incisions.

Richard Orlando, M.D., a partner in Columbus Ophthalmology Associates in Columbus, Ohio, and a clinical investigator for the lens, says it's important to have an acrylic lens for patients who might be better suited for it. Additionally, B&L is addressing the market's demand to make smaller incisions. "There are certain instances where acrylic is a better choice," explains Dr. Orlando. "Currently most of the acrylic lenses go into a 3.2-mm incision. Our goal with this technology is to modify the insertion device so we can get sub 3."

eyeonics

	The crystalens is the only approved accommodative.

crystalens. This IOL is a modified plate-haptic lens with square edges. It's made of a third-generation, nonreflective trademarked silicone called, Biosil. The haptics are made of polyimide. The lens, the first and only accommodative approved by the FDA, comes in powers from +10D to +33D in diopter steps; however, eyeonics requires surgeons to use between 16D and 27D during their credentialing, which consists of their first 10 bilateral patients.

John F. Doane, M.D., F.A.C.S., of Discover Vision Centers, Kansas City, Mo., and clinical assistant professor, Kansas University Medical Center department of Ophthalmology, inserts this IOL in about 50% of his refractive lens replacement /cataract extraction intraocular lens implant patients. Of these, half are placed in patients with cataractous crystalline lenses and half are used for correction of refractive error /presbyopia.

"We are essentially able to achieve something today [presbyopia correction with the crystalens] that we simply could not 12 months ago -- which I think is very powerful and positive impact for the patient," says Dr. Doane.

Dr. Doane's pearls include:

► Physicians should set patient expectations appropriately about when they can expect to achieve their intermediate and near vision function goals.

► Utilize noncontact biometry and manual keratometry to achieve the highest percentage of patients with postoperative emmetropia as possible. This creates the best scenario for the crystalens to provide optimal intermediate and near visual function.

► Correct corneal astigmatism. Visually significant residual astigmatism will reduce best overall visual function at near, intermediate, and distance focal points.

Staar

	The STAAR silicone lens can be implanted through a 3-mm or 3.2-mm incision.

Collamer. This is a single-piece plate haptic lens that is made of a collagen-copolymer. The lens power ranges from +10.5D to +34.0D, and is available in 0.5D increments.

In a comparative study, R. Gale Martin M.D., found that this IOL reduced the number of induced higher-order aberrations when compared with acrylic and silicone lenses.

With good visual outcomes, Elizabeth Davis, M.D., FACS, partner at Minnesota Eye Consultants, reports patient satisfaction as the IOL's greatest benefit. Dr. Davis estimates she implants this lens in approximately 30% of her patients.

Dr. Davis' three surgical pearls are:

► Because the Collamer is a plate implant, it succeeds best when a large capsulorhexis is made. "If a small capsulorhexis is created, capsular contraction/phimosis is more likely. Should this occur, the implant can then buckle and cause a refractive shift," explains Dr. Davis. She says if this does happen, the plate IOL usually flexes posteriorly resulting in a hyperopic shift. The less common anterior flexion would create a myopic result.

► The delivery of this IOL is via a plunger system. It is important that the surgeon use a pumping action instead of a single push to deliver the Collamer. If the physician uses a single push, the plunger can override the implant and truncate the trailing haptic. The newest Indigo injector system essentially eliminates this problem.

► The use of a generous amount of viscoelastic when loading the lens in the cartridge is also critical. In the ideal situation, the plunger tip never actually contacts the IOL. Rather, the IOL is advanced down the injector by a column of viscoelastic that is propelled ahead of the foam-tipped plunger. This also prevents plunger override of the lens.

Silicone 3-piece. This 3-piece lens has a silicone optic and polyimide haptics. It comes in powers from
+1.0D to +30.5D and 0D to -4D -- from -4D to +9D in 1D increments; from 9.5D to 30.5D in 0.5D increments.

As a refractive surgeon who primarily uses IOLs for refractive lensectomies, Paul Dougherty, M.D., principal of Camarillo, Calif.-based Dougherty Laser Vision, uses this IOL as a backup to the Collamer plate lens and for patients who have unusual refractive errors.

"This is the only lens I am aware of that has a minus power lens for very high myopes," says Dr. Dougherty.

For patients that fit into this high refractive error category as well as those patients who don't have a perfect capsular bag to implant a plate lens, the silicone 3-piece offers a large 6.3-mm optic to minimize glare and halo effects.

Dr. Dougherty provides these pearls:

► Utilize this lens when there isn't a perfect capsulorhexis at the time of the surgery.

► When injecting the lens, a 3-mm or 3.2-mm incision will suffice for the cartridge tip of the injector.

► Consider using this lens for refractive lensectomy as an alternative to LASIK for patients over age 50 with high refractive errors.

Down The Road

As IOLs continue to improve, wavefront technology is expected to have an increasing role. Wavefront has already been used to design aberration-free and negative-aberration lenses, and it's likely that a new class of lenses will emerge.

"We are learning more about vision, and it is more than just acuity; it's about contrast sensitivity and understanding aberrations of the entire optical system," states Dr. Chu. "Wavefront-designed IOLs are the first step towards combining these technologies."