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Although expressing different levels of enthusiasm for accommodative IOLs, clinicians debating the merits of this technology agreed that the devices have promise and said they look forward to improvements and new designs.
I. Howard Fine, MD, clinical professor of ophthalmology, Oregon Health & Science University, Portland, and Sandy T. Feldman, MD, MS, Clear View Eye and Laser Medical Center, San Diego, weighed the merits of accommodating IOLs in presentations during the Refractive Surgery Subspecialty Day here at the American Academy of Ophthalmology annual meeting.
"Multifocal IOLs require no accommodative effort, and that is an advantage, but they do require central nervous system adaptation. They will always have some halos or blur. There is some loss of contrast sensitivity, and they may be a very bad choice for patients with age-related macular degeneration," Dr. Fine said.
The first presbyopic IOL was a foldable silicone multifocal IOL (Array, Advanced Medical Optics [AMO]), an aspheric design with the entire refractive sequence in each of five concentric zones. A pivotal clinical trial showed that 41% of patients in whom the lens was implanted bilaterally required no spectacles, although spectacle independence was not guaranteed.
In Dr. Fine's experience with refractive lens exchange in these patients, 44% achieved spectacle independence and saw at least J2 and 20/25. Halos around point sources of light at night have been a common problem with this lens, but this problem tends to improve or resolve over several months, he said.
Over time, IOL technology has improved, and more designs are being tested or on the market. One multifocal lens (Tecnis, AMO) is well accepted in Europe and is undergoing FDA trials in the United States, Dr. Fine said, whereas another lens (crystalens, eyeonics) has FDA approval and achieved very good results in FDA clinical trials and in patients undergoing refractive lens exchange. Another accommodative lens (Akkommodative 1CU, HumanOptics) is available on the international market.
"Theoretical considerations show that a dual-optic IOL that moves in the eye has a higher amplitude of accommodation than a monocular IOL," Dr. Fine said.
Deformable IOLs may be the most promising technology, he continued. One (NuLens, NuLens Ltd.) has a flexible polymer between two plates. With accommodative effort, the polymer is pushed into an aperture in the anterior plate, resulting in a marked change in the curvature and a marked increase in the spherical axis.