An excerpt from an article written by Christopher Kent, Senior Associate Editor for Ophthalmology Management magazine that discusses expected advances in Intraocular Lens (IOL) availability to refractive surgeons.

"We're experiencing an incredible flowering of new technology for pseudophakia."

Enhancing Vision Quality. Updated FDA labeling for the Tecnis IOL (Pfizer, New York, N.Y., in the process of being acquired by Advanced Medical Optics, Santa Ana, Calif.) states that it improves highway safety by improving functional vision. The complementary prolate design of this lens reduces spherical aberration based on a population average cornea model. (For more Tecnis news, see page 39.)

Customization. The innovative Light Adjustable Lens from Calhoun Vision (Pasadena, Calif.) remains an exciting prospect as well because it offers the potential for true customization of an IOL after implantation. Once the IOL is stable in the eye, it's irradiated with ultraviolet light, which creates fine adjustments in the lens to achieve perfect correction of defocus, astigmatism and higher-order aberrations. The correction in the lens can be readjusted until the desired goal is achieved, and then locked in. Information from off-shore trials has been reported by Daniel Schwartz, M.D., and we eagerly await initiation of clinical trials in the United States.

Bimanual Microincision Phaco. This type of surgery has created exceptional interest over the past year. Bimanual phaco courses and talks have remained well-attended, and Jorge Alio's new book, Microincision Cataract Surgery (Highlights of Ophthalmology, 2004) was a best-seller at the recent ASCRS Symposium in San Diego. However, it's unlikely that this type of surgery will become widely adopted until IOLs that can be implanted through incisions smaller than 1.5 mm become available. The first prospect in the United States is the Thinlens from ThinOptX (Abingdon, Va.), a diffractive implant only 100 microns thick with a range of correction from -25D to +25D. Results from Europe are promising, particularly in terms of improved quality of vision, but concerns remain about long-term stability with capsular fibrosis. (For more Thinlens news, see "Also Happening This Year" on page 40.)

Prevention of Capsular Fibrosis. This remains a topic of interest for cataract surgeons, but the interplay between IOL edge design and dysphotopsia has created an issue for manufacturers. Surgeons would much rather perform a YAG capsulotomy than deal with ongoing patient complaints of peripheral scotoma or edge glare. The degree of dysphotopsia depends not only on edge design, but also on the properties of the IOL material, including the refractive index and reflectivity. One new IOL in clinical trials that may have found a way to resolve this problem is the C-Flex from Rayner (Hove, East Sussex, UK). (For more on this, see "Also Happening This Year" on page 40.)

Ready to Ride the Wave. As Howard Fine, M.D., is fond of saying, "The story of IOLs is still unfolding." And while the next 12 months won't bring us all of the innovations described above , there can be no doubt that within a few years technology will change the landscape of cataract and refractive lens surgery.

In the meantime, get ready for innovation and growth in cataract and refractive lens surgery practice, starting with the (following) products:

		Alcon expects to launch two products within the next 12 months: the AcrySof ReSTOR "pseudoaccommodative" lens, and the AcrySof Toric IOL. Alcon expects to launch two products within the next 12 months: the AcrySof ReSTOR "pseudoaccommodative" lens, and the AcrySof Toric IOL. The AcrySof ReSTOR IOL. The AcrySof ReSTOR IOL is now in the final phases of FDA trials. Unlike accommodative lenses, it doesn't depend on contraction of the ciliary muscle to move the lens to create a range of vision. Instead, it creates good near and distance vision by combining apodized diffractive and refractive optics.
Alcon's AcrySof ReSTOR IOL combines apodized diffractive and refractive optics to create a range of vision.

A central 3.6-mm diffractive region facilitates both near and distance vision; this gradually blends into the outer (refractive) portion of the optic through a controlled step height reduction called "apodization." When the pupil is constricted, incoming light is equally divided between near and distance vision; when the pupil is enlarged, as in low lighting conditions, the light distribution becomes distance-dominant. Clinical results are showing a reduction in the incidence of glare and halos, which the company attributes to the apodization process.

Robert P. Lehmann, M.D., clinical associate professor of ophthalmology at Baylor College of Medicine in Houston, presented the FDA clinical study results at ASCRS. The study found that 81% of patients implanted with the MA60D3 AcrySof ReSTOR lens never wear glasses (compared with 8% of those with monofocal implants). If you include patients who report "sometimes" wearing glasses, the number rises to 97%. In another arm of the FDA study, conducted by Kerry Solomon, M.D., and David T. Vroman, M.D., at the Storm Eye Institute in South Carolina, 95% of patients implanted with the lens said they'd choose to have it implanted again.

		According to Alcon, the ReSTOR lens has the same biomaterial benefits as previous AcrySof IOLs. AcrySof Toric. Alcon says it hopes to file for approval of the Toric version of AcrySof sometime in the next 6 months. According to the company, the AcrySof single-piece lenses are known for their centration and stability in the capsular bag -- a crucial factor for a toric IOL -- as a result of their adhesion to the capsule and a "profound shrink-wrap effect." Dots near the periphery of the lens delineate the axis of the cylinder to aid alignment on the steep meridian.
Alcon's AcrySof Toric has shown minimal rotation in FDA clinical trials.

As part of the FDA clinical study, 250 AcrySof Toric implants have been evaluated for rotation. The cumulative data was presented by Paul Ernest, M.D., at ASCRS. The data showed that the mean rotation at 3 months was 4°; 83% of the implants rotated less than 5°; and none rotated more than 15°. For comparison, another popular toric lens was included in the study; 5% of those implants rotated more than 30°, enough to negate the astigmatic correction.

		AMO will be offering several new options during the coming year: Extended diopter range. This Spring, AMO announced the availability of an extended diopter range for its ClariFlex IOL with OptiEdge. This summer, AMO will be launching a similar range expansion for its acrylic IOL, Sensar, which also features the OptiEdge design. Like the ClariFlex, the Sensar will soon be available. This will make AMO the only U.S. company offering the extended low diopter range in both acrylic and silicone.
AMO's Sensar IOL will soon join the ClariFlex in having an extended low diopter range.

The OptiEdge design features a squared posterior edge that creates 360° capsular contact to help prevent posterior capsular opacification (PCO), and a rounded anterior edge to reduce internal reflections by scattering light. The edge is slanted overall, to minimize the potential for edge glare.

Promoting the Tecnis lens. As mentioned previously, AMO is in the process of acquiring the assets of Pfizer's surgical ophthalmology business, including Pfizer's Tecnis IOL, which recently received FDA approval for new labeling claims. The lens was designed to minimize spherical aberration (which many standard IOLs actually increase), and thus improve what the company calls "functional vision" -- the ability to see well in varying light conditions. Clinical trials demonstrated that patients implanted with the Tecnis lens produced significantly better simulated night driving results and had better visual acuity as a result of reduced spherical aberration. (The new labeling states that the lens reduces postoperative spherical aberration and has improved patients' night-driving simulator performance.) AMO was unable to comment on plans for the lens in the next 12 months because the transfer of ownership has not been completed. (A multifocal version of the Tecnis should begin clinical trials later this year.

The next-generation lens. According to Jim Mazzo, president and CEO of AMO, the company will introduce a new model of the multifocal IOL this year. The new lens will use an acrylic platform and feature AMO's proprietary OptiEdge design.

		B&L plans to introduce two new products during the next 12 months: A new Soflex IOL designed to lessen spherical aberration, and a new "foolproof" injector system. The Soflex AO. At the end of the year, B&L plans to add this aspheric IOL to the Soflex line of silicone lenses. (The AO stands for "Advanced Optics.") The new lens reduces spherical aberration compared with a conventional lens.
B&L's forthcoming Soflex AO lens reduces positive spherical aberration compared with a conventional IOL, using a design that's not affected by decentration or tilt.

STAAR is planning to launch a 3-piece version of its Collamer IOL, along with a new injection system.

A new study conducted by Robert G. Martin, M.D., found that the collamer IOL has 55% to 117% fewer induced higher-order aberrations than acrylic or silicone materials; as a result, it produces less post-op glare. Another study by Elizabeth Davis, M.D., found a statistically significant reduction in the amount of flare and inflammation produced by implantation of a collamer lens, compared with an acrylic lens.

Other IOL-related developments include:

In clinical trials. Several IOLs are under investigation:

		ThinOptX is currently setting up investigational sites for a multicenter FDA clinical trial -- the first large-scale study of the Thinlens, an ultra-thin IOL designed to be injected following microincision phacoemulsification. Enrollment of 400 patients at 10 sites should begin shortly.
		Eyekon Medical, based in Clearwater, Fla., has an acrylic IOL currently undergoing FDA clinical trials. The company notes that this lens is hydrophilic, very similar to the natural crystalline lens of the eye, which is expected to be a major selling point.
		The C-Flex IOL from Rayner (Hove, East Sus-sex, UK) is currently in clinical trials here in the United States. The C-Flex is a hydrophilic acrylic lens with a modified edge designed in collaboration with David Apple, M.D. Mark Packer, M.D., has been implanting the lens as part of the trials. He reports: "In my experience the lens remains exceptionally well-centered, and the capsule continues to look perfectly clear." (See photo, above.) "The patients implanted with this lens at our center have so far not complained of dysphotopsia."