This month’s cover focus is dedicated to the hot topic of accommodating IOLs. Surgeons and patients agree that, once symptoms of presbyopia are evident, it would be ideal to have a technology that could restore the crisp vision of a 30-year-old at all distances. Many ophthalmologists, engineers, and inventors are searching for the holy grail—the perfect accommodating IOL—that would deliver long-term performance without the issues of predictability, safety, or unwanted lens capsule changes.
We know that today no such lens exists; none is even expected to be available for routine clinical use in the next few years. However, a variety of available accommodating IOLs provide patients with something we ophthalmologists have termed pseudoaccommodation. Currently, many surgeons rely on these and other presbyopia-correcting IOLs, each of which comes with its own set of pros and cons. A variety of multifocal IOLs with different optical properties are available; however, all designs share the same compromise of splitting light and therefore imparting some degradation of image quality.
Single-optic accommodating IOLs have attracted much attention, and some surgeons have used or still use them, including the Akkommodative 1CU (HumanOptics AG, Erlangen, Germany), the Crystalens (Bausch + Lomb, Rochester, New York), the Tek-Clear (Tekia, Inc., Irvine, California), and the Tetraflex (Lenstec, St. Petersburg, Florida). New designs appear and disappear, but the debate over whether single-optic accommodating IOLs work is ongoing. Recent scientific data indicate that there is very little objective pure lens shift effect and that pseudo accommodation and/or lens-optic flexing is the source for intermediate and some near vision with these IOLs.1,2
It is fascinating that spherical aberration induction is integrated into this discussion. I am a little startled when optical scientists defend the complete correction of spherical aberration to obtain perfect vision at a certain distance, rather than the induction of spherical aberration to create greater depth of field. Maybe we should dedicate a cover focus to the topic of spherical aberration and its influence on image quality versus depth of focus.
In addition to the discussion about pseudo- or real accommodation, we should not forget the option of mini, moderate, or full monovision, which many colleagues use successfully to provide a certain degree of spectacle independence.
Recently, Abbott Medical Optics Inc. (Santa Ana, California) launched the Synchrony accommodating IOL in Europe. Its dual-optic concept provides a reasonable amount of accommodation, with 5-year data indicating long-term preservation of action. But this IOL is still in its infancy, and more clinical data are needed to convince ophthalmic surgeons of its long-term efficacy and safety.
The innovative and completely new concepts for restoring accommodation such as the NuLens DynaCurve (NuLens, Ltd., Herzliya Pituach, Israel), the FluidVision (PowerVision, Inc., Belmont, California), and the SmartIOL (Medennium, Inc., Irvine, California), although interesting, are in very early clinical research phases. It is obvious that incorporating a true accommodative effect into an IOL, without significant drawbacks, is not easy to accomplish. However, I am hopeful that we shall reach the holy grail—hopefully before it is time for my own cataract surgery.
In order to provide more insight into the world of accommodating IOLs, we asked a panel of experts including Victor Bohórquez, MD; Sheraz M. Daya, MD, FACP, FACS, FRCS(Ed), FRCOphth; Robert K. Maloney, MD; Samuel Masket, MD; Mark Packer, MD, FACS; Magda Rau, MD; and Sunil Shah, FRCOphth, FRCS(Ed), FBCLA, to answer five questions about the various accommodating IOLs on the market or in the pipeline. From their answers, you can perceive that there is still a lot of skepticism, but also hope for the future.
I have not yet used any of the accommodating lenses available today, but I am interested in what the future will bring—the holy grail or the garbage bin.