This article is more than 5 years old. Information may no longer be current.
Which is the future of presbyopia correction, multifocality or accommodation, and why?
Click Here to Manage Email Alerts
True accommodation is the ultimate solution
 Jack T. Holladay |
Multifocality has never been considered anything but an interim step along the way toward the successful treatment of presbyopia in pseudophakia. Multifocality by definition is associated with reduction in contrast, loss of best focus and the association of nighttime dysphotopsias, the latter being the most significant in dissuading surgeons and patients from choosing this modality for their IOL with cataract surgery. For the past 20 years, multifocality has never reached a market share greater than 5% due to these limitations. The “true” solution must provide at least 4 D of actual accommodation (not pseudoaccommodation) or more, as determined by measuring the actual amplitude of accommodation. Novel mechanical methods, such as the Synchrony IOL (Abbott Medical Optics) and the FluidVision IOL (PowerVision), and electrical methods that can change the power of an IOL by changing the index of refraction of the material are in the pipeline (minimum of 5 to 7 years away from approval), appear promising and satisfy all of these requirements. A method that provides the necessary accommodation will not have loss of contrast or resolution and will have no nighttime dysphotopsias. The answer, by definition, is accommodating, and anyone who disagrees has no understanding of basic optics, specifically multifocality.
Jack T. Holladay, MD, MSEE, is OSN Optics Section Editor. Disclosure: Dr. Holladay is a consultant to Abbott Medical Optics and Nidek.
There will still be a place for multifocal IOLs
 David F. Chang |
Like everyone, I look forward to using future generations of accommodating IOL technology. We all concur that a more continuous range of focus, improved contrast sensitivity and reduction of unwanted images, such as halos, would be significant improvements over the inherent optical tradeoffs of multifocal IOLs. Even after superior accommodating IOLs are approved, however, I predict that we will still use multifocal IOLs to correct presbyopia in some patients. One big reason will be cost. The top digital cameras priced at $1,000 today will cost $300 in 2 years. At that time, they will nicely fit the needs and budgets of many consumers who will not want to spend $700 more for the extra benefits of the newest model. The same will be true of multifocal IOLs a decade from now, assuming that they will be priced substantially lower than the latest accommodating IOLs. Aspheric diffractive multifocal IOLs are an excellent functional solution for many patients. Particularly after toric multifocals become available, they will have a lower enhancement rate than many accommodating IOL models and will not carry the risk of loss of function due to capsular changes over time. Despite the theoretical advantages, do not assume that accommodating IOLs will render multifocal IOLs obsolete in a market where patients will continue to weigh the functional benefits against the out-of-pocket cost.
David F. Chang, MD, is an OSN Cataract Surgery Board Member. Disclosure: Dr. Chang is the medical monitor for the Synchrony accommodating IOL, and his consulting fees from Alcon and AMO are donated to Project Vision and the Himalayan Cataract Project.