Eyeworld

58 February 2015 by Michelle Dalton EyeWorld Contributing Writer EW REFRACTIVE Experts discuss innovations in IOLs D iscussing "new technol- ogy" involves more than just the next iteration of a technology or a minor (but still useful) enhance- ment. Last month, EyeWorld asked experts around the world for their opinions on extended depth and range of focus lenses. This month, EyeWorld asked about corneal inlays, accommodating, and "true" new technologies currently under inves- tigation in at least one region of the world. Here is what the experts said. Where the interest lies One of the biggest challenges for cataract surgeons today is that most lenses will improve best corrected vi- sual acuity (BCVA), "but we still ha- ven't nailed the refraction. We still have issues with IOL predictions and accuracy, and there are still some patients who will develop posterior capsule opacification [PCO] after surgery," said Arthur B. Cummings, MB ChB, FCS(SA), MMed(Ophth), FRCS(Edin), consultant ophthalmol- ogist at the Wellington Eye Clinic and Beacon Hospital, Dublin. The Harmoni lens (ClarVista, Aliso Viejo, Calif.) not only boasts the lowest PCO rate of any cur- rently available lens (80% less PCO in rabbit studies), but it will allow surgeons to swap out the optic in the case of a refractive surprise while the haptics remains in place in the capsular bag. "This lens has an amazingly stable base because of the haptic New technology IOLs: where innovation lies configuration and a capsular tension ring built around the lens," Dr. Cummings said. With a "completely interchangeable optic," he thinks that the lens will also have great potential in pediatric cases in addi- tion to the traditional premium lens patient. Jorge L. Alio, MD, PhD, pro- fessor and chairman of ophthalmol- ogy, Miguel Hernandez University, Alicante, Spain, and medical director of Vissum Corporation, Spain, has discussed the 16-month results in 52 cases implanted with the Lumina IOL (AkkoLens, Breda, the Netherlands) in Bulgaria, said Liliana Werner, MD, PhD, asso- ciate professor, and co-director of the Intermountain Ocular Research Center, John A. Moran Eye Center, Salt Lake City. The range of accom- modation obtained was 2 D to 5 D, and the "hydrophilic acrylic lens has shifting cubic optical elements designed to be implanted in the sul- cus. The focal length is supposed to change when the refractive elements shift laterally. Long-term clinical results will tell if constant shifting of the optic elements will result in problems such as pigmentary disper- sion," she said. "Outcome variability is an issue in pseudophakic accommodation, but at this moment, we have a lens that really works," Dr. Alio said. "As it is a sulcus lens, safety issues still have to be solved during this year." As the Light Adjustable Lens (LAL, Calhoun Vision, Pasadena, Calif.) becomes available in certain markets, research is being performed on other IOLs that can be adjusted noninvasively in the postoperative period such as liquid crystal IOLs with wireless control and IOLs that can be adjusted by using the femto- second laser or 2-photon chemistry, Dr. Werner said. (See this month's "Device focus" for an in-depth look at the LAL.) These other lenses are all in early stages of development. Multicomponent IOLs that can be adjusted by surgical exchange of the optic component only, while the base component remains in place, are also under clinical evaluation, from developers Infinite Vision Optics (IVO, Strasbourg, France) and ClarVista Medical, she said. True accommodation? The group of Dr. Werner and Nick Mamalis, MD, has evaluated the FluidVision accommodating IOL (PowerVision, Belmont, Calif.) in "different rabbit studies and ob- served that overall capsular bag opacification with this lens was remarkably low in comparison to a commercially available control." The lens incorporates large, hollow haptic elements that keep the an- terior and posterior capsules apart. The optic and haptics are made of a hydrophobic acrylic material, and the haptics and interior of the optic are filled with silicone oil that is index-matched to the acrylic, she said. The lens is designed "so that when the haptics are subjected to accommodative forces, silicone oil is pushed into the optic through fluid channels that connect the haptics to the optic. As silicone oil flows into the optic, the deformable front optic surface is changed, increasing the power of the lens," she said. The lens is under evaluation in Europe. The lens may enter U.S. tri- als as early as the first half of this year, said Mark Packer, MD, CPI, medical director of Boulder Eyes, Boulder, Colorado. Some of the data coming out of the European mul- ticenter studies indicates the lens "changes shape, and the company can correlate the shape change to an amount of accommodation by measuring the surface curvature of the fluid-filled bag," he said. In some studies, the accommodation has been as high as 5 D, he added. Dr. Mamalis, professor of ophthalmology, co-director of the Intermountain Ocular Research Center, and director of ocular pathology, John Moran Eye Center, Correcting astigmatism I n Europe, toric lenses are typically prescribed "for anything that is about 2 or more diopters," Dr. Alio said, and for anything under 1.5 D, he will use opposite clear corneal incisions. In Spain, the national healthcare system will prescribe toric lenses, but not multifocals. Limbal relaxing incisions "are prevalent but they are performed manually as they add an extra cost that is inadequate, financially, for doctors. Toric lenses have a higher value but indeed are considered as worthwhile by most doctors," he said. In Ireland, "given the state of the lenses that we have freely available right now, I think the market that's growing quickest is definitely toric, much quicker than multifocals," Dr. Cummings said. In his clinic, Dr. Cummings discusses toric lenses with patients with more than 1.5 D of astigmatism "and 8 out of 10 opt for the lens. The additional 350 euros copayment is a negligible cost considering the benefit." However, if the patient has toric corneas but an asymmetric astigmatism, "I don't think toric IOLs are the best option in these asymmetric cases," Dr. Cummings said. "In these cases, I normally put a spherical IOL in and do a topography-guided LASIK treatment to make the corneal surface as symmetrical as possible and as spherical as possible. I believe that a spherical IOL with a spherical cornea gives you a better result than a toric cornea corrected by a toric IOL." In the U.S., Dr. Mamalis prefers toric lenses, "because I'm not a refractive surgeon. I don't do LASIK or PRK, but I find the toric lenses are very adept at correcting the higher levels of astigmatism." EW " The holy grail is being able to provide clear vision in both eyes; to get an implant that truly does accommodate; and to have an implant that gives a wide enough range of focus. " –Nick Mamalis, MD

• Cover