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BLOG: EDOF lenses in post-refractive eyes
Millions of people around the world have undergone refractive surgery procedures, including LASIK, PRK and RK. These patients have already demonstrated an interest in refractive surgery and a willingness to pay out of pocket for the lifestyle benefits of refractive surgery.
I have a large post-refractive population in my practice, and I’m finding that as many of these patients develop presbyopia and cataract, they have a strong interest in restoring or maintaining their relative spectacle independence. Of course, we know that prior surgery makes IOL power calculation more challenging and less predictable. In the past, if a post-refractive patient had a relatively regular cornea, I might have considered implanting a low-add multifocal — but that was the exception, not the rule.
One of the things we have learned from our international colleagues is that extended depth of focus (EDOF) lenses may allow us to offer presbyopia-correcting IOLs to patients we would not previously have considered as candidates for multifocal IOLs. There are several reasons for this. First, the EDOF optics do not impact contrast sensitivity in the same way that multifocal optics did. Second, optical bench and clinical defocus curves from clinical trials of both the Tecnis Symfony (Johnson & Johnson Vision) and the IC-8 (AcuFocus) lenses suggest that these IOLs may be forgiving of residual sphere or cylinder. In theory, in post-RK eyes with diurnal fluctuation, an EDOF IOL may be an ideal way to manage this issue, and we have had good success with this approach.
Since the Symfony was approved for use in the U.S., I have implanted it in the majority of my post-myopic LASIK patients and those who had RK with eight or fewer cuts. The Symfony lens has the highest available negative spherical aberration, which helps to compensate for the induced spherical aberration in a post-myopic LASIK eye.
I would recommend becoming comfortable with EDOF lenses in virgin eyes first, and then eventually choosing post-refractive eyes in which the irregularities are relatively symmetrical.
Additionally, no matter how “forgiving” the lens is, it is imperative to follow all the tenets of good surgery in these more aberrated eyes.
For example, surgeons should treat the ocular surface before and after surgery, and be meticulous with biometry, IOL power calculation, astigmatism measurement and correction, and refractive targeting. Residual refractive error may certainly affect the performance of these IOLs and may require enhancement. It is also important to provide informed consent about the increased possibility of dysphotopsia and the potential need for enhancement or even lens exchange.
My post-refractive patients have done very well with EDOF lenses. I’m thrilled that EDOF technology has allowed me to provide a presbyopia-correcting solution to some of my challenging but most highly motivated patients.
Disclosure: Waring reports he is a consultant for Johnson & Johnson Vision and a member of the Johnson & Johnson Vision optics advisory board.