If eye surgeons are asking you to add new, more expensive IOLs to your inventory, and you've had trouble making a decision, here's help. So that facility managers can make informed decisions, we asked companies and physicians to explain the significance of the new IOL features, including blue-light blocking, modifications in edge design and aspheric optical designs. Here's what they said.

Blue light special
Alcon expects the FDA to shortly approve its AcrySof Natural SB30AL IOL (Fig. 1). Alcon has been working on the foldable, single-piece IOL, which features blue-light blocker in the form of a yellow chromaphore bonded to the IOL, for several years.

Alcon believes blocking blue light may help prevent age-related macular degeneration, a relatively common, debilitating eye disease. Vice President and General Manager Bill Barton points to several studies suggesting that cataract patients may need blue-light protection:

• A Wisconsin study indicates that cataract surgery increases the risk for late ARMD.
• A Maryland study shows that exposure to large amounts of visible light increases the risk for ARMD.
• A Japanese study suggests that eyes implanted with blue-light filtering have a lower incidence of blood retinal barrier disruption than in eyes with an untreated IOL.

According to company research, the AcrySof SB30AL blocks UV light and most light between 400 and 450 nm. Alcon says it blocks more than 90 percent, making it better at filtering blue light than the natural lens (Fig. 2). A drawback is that some patients may not be able to see blue hues as well.

Alcon has also reduced the thickness of the lens and its edge and, according to Mr. Barton, "people are consistently inserting this lens through a 3mm incision or smaller."

Squaring-and rounding-off
Several companies have modified their edge designs. They are placing squared off edges on the posterior of the optics to to impede cell migration into the central optical zone, preventing posterior capsule opacification (PCO), a clouding of the capsule behind the IOL after insertion. And they are modifying the anterior edges to compensate for optical problems that the squared edges can create.

Advanced Medical Optics, or AMO, released the Clariflex and Sensar with OptiEdge early in 2002.

The Clariflex is a foldable silicone IOL designed to fit through a 3-mm incision, and is an update on the SI40 (Fig. 3). The lens was launched early in 2002, and physicians are now better able to report on the results in their facilities.

OptiEdge - AMO's name for its design that pairs squared posterior and rounded anterior edges - facilitates contact with and stability within the capsular bag, according to the company. According to clinical trials, the capsular bag contact caused by OptiEdge results in lower intensity of internally reflected light than square- or round-edged IOLs.

The lens was launched early in 2002, and physicians say it's performed well.

"It has improved optics and decreased incidence of PCO," says Elizabeth Davis, MD, with Minnesota Eye Consultants in Minneapolis.

She adds that the Clariflex is easy to implant through a 2.8 mm incision. "In terms of transition, it's similar to the SI40 lens (a Phacoflex II model)," she says. "Injection, handling the implant and the predictability of refractive outcomes is the same. There's really no learning curve."

"Few patients have imagery on the side of their vision - I'd say less than 3 percent," says R. Bruce Wallace, MD, of Alexandria, La. "And it's possible to implant it even if the capsular bag is torn."

Dr. Wallace chooses the Clariflex for most patients because it's so easy to use. He says he uses the acrylic Sensar for patients with retinal disease, in case the patients eventually need silicone oil, which is widely considered to be incompatible with silicone IOLs.

Only three features of the Sensar differ from the Clariflex: its haptics have 5-degree angulation (Clariflex is 10 degrees), it fits through an incision as small as 3.2 mm and it's acrylic.

Dr. Davis says none of her Sensar patients thus far have needed YAG surgery.

Bausch & Lomb also has a new edge design for its SoFlex silicone IOL. The new SoFlex SE features a squared off posterior edge to facilitate complete capsular contact and reduce cell migration and incidence of PCO. The company doesn't use a rounded anterior edge, though; it says the equi-biconvex design does a better job of directing glare toward the periphery of the retina, reducing unwanted optical images.

When used with the MPort SI, the SoFlex SE, folded like an accordion, can be implanted through a sub-3mm incision.

Another lens with improved edges is Ciba Vision's CV232SRE - SRE for square-round edge. This lens, introduced last fall, also features a squared edge on the posterior side and a rounded edge on the anterior side. According to the company, this facilitates 360-degree capsular contact and decreases glare, compared to a square edge. Uniquely, this lens comes pre-rolled, although you must use forceps rather than an injector to place the lens in the eye. The lens then unfurls itself and centers as it warms to body temperature. Proponents of the lens think this method is safer for the capsule, but some have complained that watching the lens unfold can take 15 minutes and is not efficient in a busy OR.

The lens is multipolymer acrylic but the haptics are polypropylene, which is stronger than PMMA and, according to Ciba, makes bacterial adhesion more difficult. The company reports low rates of bacterial adhesion in its trials. Patients who received the lens made no reports of glare.

Improving spherical aberration
The silicone Tecnis z9000 (Fig. 5), by Pharmacia, is an aspheric IOL; it has a prolate, or bullet-like shape, with different curvatures at different areas. The idea is to compensate for the spherical aberration of the cornea. In the young phakic eye, the cornea provides positive spherical aberration and the crystalline lens provides negative, canceling out each other. Traditional IOLs do not compensate for this optical issue. So when they are implanted, especially during low light conditions when the pupil is dilated, some light rays will not be focused on the retina. The patient may still see 20/20 on a Snellen chart, but more refined tests such as contrast sensitivity will show that vision is not as sharp. The Tecnis incorporates negative spherical aberration, in an attempt to mimic the young crystalline lens's ability to offset the aberration of the cornea.

According to a recent study, patients with the Tecnis do achieve better contrast sensitivity in low light levels than do patients with traditional IOLs.

The Tecnis can be inserted through an incision of "2.9 [mm] to 3.2, depending on insertion technique," says Jack T. Holladay, MD, MSEE, FACS.

One drawback: Pharmacia does not market an injector for the Tecnis, so the IOL must be inserted with a folder or another company's injector. According to Dr. Holladay, a "Pharmacia 'shooter' should be available within three months."

Even without a Tecnis-specific injector, Mark Packer, MD, reports good results.

"We have not yet seen any significant PCO or performed any YAGs, with about 200 implantations and about 18 months follow up," says Dr. Packer, a clinical assistant professor for the Casey Eye Institute at Oregon Health & Science University.

Choosing an IOL
The new features these new lenses offer could improve safety, vision and quality of life for cataract patients. But because they will be more expensive than standard silicone lenses, and because the reimbursement system is perverse, facility managers and physicians will have to decide for themselves how much value they add and whether the improved technology justifies the additional cost.

Dr. Packer, for one, casts his vote for the new technology.

"If cost were the key, we would still be implanting standard-power one-piece PMMA IOLs through 7-mm incisions," says Dr. Packer. "Instead we are customizing IOLs with optical biometry and fourth-generation calculation formulas, and foldable lenses have become the standard of care."