EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/387844
EW SECONDARY FEATURE 86 October 2014 by Ellen Stodola EyeWorld Staff Writer IOL innovations outside the U.S. Presbyopia-correcting options differ for patients around the world I OL options for presbyopia cor- rection differ from country to country. Outside the U.S., there are a number of technologies being tested and used to treat patients, including trifocal IOLs, types of accommodating IOLs, and other unique technologies. Addi- tionally, many other ideas are com- ing to light to treat these patients. Damien Gatinel, MD, PhD, Rothschild Foundation, Paris, and Richard Lindstrom, MD, Minnesota Eye Consultants, Minneapolis, discussed which technologies they are using and what they see potential for in the future of presbyopia correction. Trifocal IOLs Trifocal IOLs offer different advan- tages than the normally bifocal IOLs, and Dr. Gatinel has experience working with these types of lenses. "I have engineering and pioneering experience with the FineVision IOL, which I co- designed," he said. "It has become my main indication for premium IOL surgery in patients who seek spectacle independence." This PhysIOL technology (Liege, Belgium) provides both near and intermediate vision in addition to distance correction, and it alleviates the need for mix-and-match strate- gies. "In my experience, diffractive multifocal IOLs are more robust for any irregular corneal astigmatism than refractive multifocal ones," Dr. Gatinel said. Accommodating IOLs Dr. Gatinel has not yet found suc- cess with accommodating IOLs. "My experience with accommodating IOLs has been negative," he said. "I have not found any effective design and reproducible concept yet." Dr. Lindstrom is enthusiastic about a few technologies and ideas that are being developed for accom- modating IOLs. He mentioned the AkkoLens product (Breda, the Neth- erlands), which is currently being tested in a clinical trial in Europe. The lens uses a dual optic system with the 2 lenses moving across each other from side to side. "Instead of an in-the-bag lens, it's in the ciliary sulcus, so it's pushing against muscle when it accommodates; it's a more reliable power source," he said. "That lens is showing promise to be a real accommodating intraocular lens that can generate accommodat- ing amplitudes superior to what we recognized in early technologies." Other ideas not currently in patients may be good options for presbyopia correction, Dr. Lindstrom said. One concept proposes using interface fluids so that when the patient looks down, the power increases, and when the patient looks straight ahead, the power of the lens decreases. "It's been very difficult to develop an accommodating intraoc- ular lens," Dr. Lindstrom said. One issue with this is fibrosis. "After you remove a cataract, the capsular bag undergoes fibrosis and loses its ela - ticity, and the amount of elasticity that it loses is different for every patient," he said. This means that in some patients, even though a lens could work, the capsular bag is totally rigid. Even though the ciliary muscle is doing its work and changing shape and accommodating, the capsular bag does not change shape. The forces generated have created a challenge. "We have not learned how to eliminate that problem," Dr. Lindstrom said. One way to possibly eliminate it is to bypass the capsular bag and go right to the ciliary mus- cle and use force generated directly rather than indirectly. "This seems promising," Dr. Lindstrom said, although surgeons generally like to put lenses in the bag. FluidVision PowerVision (Belmont, Calif.) is cur- rently working with an in-the-bag lens, the FluidVision lens, which Dr. Lindstrom said has potential. It is in trials in Germany. "It uses a hydraulic system, meaning it's using the movement of fluid, and in the periphe y it has what looks like a big inner tube," he said. "As the eye accommodates, that peripheral inner tube with fluid is compressed, and the fluid i moved through channels centrally and pushes against a very flexible membrane. That can cause meaning- ful accommodation to occur." Future of presbyopia correction? Dr. Gatinel thinks that corneal inlays, laser refractive surgery, and IOL surgery all have potential to play a significant role in the future of presbyopia correction. "Surgeons should improve the quality of patient selection to better match a specific treatment modality to the patient's visual expectations," he said. "Based on the preoperative refraction, the level of crystalline lens opacification, the pupil d - namics, and the pre-existing level of corneal multifocality, it should ap- pear that some techniques are more suitable than others in a particular eye or patient." In his work, Dr. Gatinel has found that multifocal IOLs are well tolerated by patients who have a cataract. "When the lens is clear, inlays or laser refractive surgery may be The FineVision IOL Source: Erik L. Mertens, MD, FEBOphth The AkkoLens accommodating IOL uses the ciliary muscle to move sliding aspheric surfaces laterally. Source: AkkoLens International