Surgical solutions for presbyopia abound

Lens-based surgical solutions for presbyopia include familiar IOLs and others not yet approved.

Issue: October 15, 2003

ByWilliam F. Maloney, MD

The restoration of reading vision for patients with presbyopia is shaping up to be one of the most important components of lens-based refractive surgery. We increasingly hear about the emergence of the baby boomers as an entire generation of eager candidates for a permanent surgical solution. In my last column I tried to discourage this sort of hyperbolic demographic projection that could lead us to overreach and repeat the “next new thing” problem we encountered with LASIK.

Today I want to review the various lens-based surgical solutions for presbyopia and share some of my clinical experience, which thus far is positive. As many surgeons with first-hand experience already know, there is no refractive surgical outcome that comes close to the impact of restored reading vision for a presbyopic patient.

Successful correction of a large degree of ametropia can be a life-changing experience, but even this does not often have the same impact as restoring uncorrected reading vision to a long-time presbyope. What accounts for this unexpected response from presbyopic correction? I have discussed this at length with my patients; they love to talk about the effects of their newfound reading ability.

It seems this phenomenon has to do with a feeling of restoration — regaining what had been lost — of their “natural” vision. In contrast with the ametrope, who often describes feeling like a new person with vision they never knew before, these patients describe a sense of regaining what was theirs, in some way feeling whole again, once again their natural selves. One 54-year-old bald man described it this way: “Try to imagine how I would feel if I awoke one morning to find my former full head of wavy dark hair had suddenly grown back. This is better.”

Surprising to me, this kind of response has been common even among the more elderly patients who have requested reading vision correction at the time of cataract surgery. I had mistakenly presumed that at their age the majority would see this as an option they would have considered “if only I were younger.” As it turns out, after regaining the reading ability that had been lost for decades, many patients in their 70s and even 80s have been some of the most vocal advocates of restored reading vision.

Some cataract patients feel they have worn glasses for so long that, in their words, “I wouldn’t feel myself without them,” but this stereotype is far from the rule and in my experience should never be assumed or taken for granted.

Whatever the reasons for this kind of response, it has become clear to me that when the restoration of reading vision fully meets the patient’s needs, it is a deeply satisfying experience that almost always exceeds their expectations. This sets a high standard, and I believe the ability to consistently meet this standard depends very much upon the approach used. The approaches for lens-based presbyopia correction are discussed here.

Accommodating implants

At this juncture, it seems that most surgeons considering the correction of presbyopia are waiting for the launch of one of several accommodating implants on the horizon. While the Food and Drug Administration clinical trial data are somewhat encouraging so far, there is much we still need to learn about this technology. There are important questions as to whether or not the amplitude of accommodation is significantly greater than the pseudoaccommodation experienced with standard “static” posterior chamber implants.

Also, because their accommodative effect derives primarily from optic travel, there are questions about the sustainability of accommodation once capsular fibrosis occurs. Smaller optics may also result in unacceptable glare, particularly in younger patients with larger pupils.

Realistically, this technology, though full of potential, is in its infancy. The concept is a significant technological leap, and we likely have much to learn before it can become the mainstay of presbyopia correction. This is particularly true in light of the currently available solid alternatives that have much to offer.

Multifocal implants

This technology has been evolving in fits and starts for 20 years. The Array (Advanced Medical Optics) represents a significant advance; it is the first multifocal to stand the test of time. Provided that the limitations — night halos and insufficient add power for fine print are commonly reported — are strongly emphasized and expectations are carefully controlled, the outcome with multifocal implants will result in satisfied patients when carefully selected. This approach is not for everybody, as R. Bruce Wallace III, MD, has repeatedly told us, and part of the art is learning to identify the right candidate.

The MA60D3 multifocal implant (Alcon) is currently in FDA clinical trials. It uses diffractive optics in the near-vision component, which thus far is providing better close reading vision than the Array. Time will tell if this enhanced near acuity is achieved at the expense of some distance or intermediate.

At least one advantage of the addition of the MA60D3 implant, with its enhanced near acuity, is that it may provide some variability and flexibility that has been lacking with multifocal implants. All presbyopic patients do not require the same reading capability using the same add. On the contrary — and this is one central principle I have increasingly come to understand — the correction of presbyopia must be fully customized if it is to fully meet the needs and exceed the expectations of the wide variety of presbyopic candidates.

Blended-vision implants

Almost all of my experience in correcting presbyopia has been with this approach, designed to provide a progressive blend of near-far acuity that results from the selection of a specific customized near-far IOL pairing. Unfortunately, this approach has been likened to the IOL equivalent of contact lens monovision. This is unfortunate.

Although contact lens monovision can be very useful, particularly for younger partial presbyopes, it is rarely successful in the patient population we are considering here. Why? The main reason is that contact lenses lack the property of pseudoaccommodation, a phenomenon that is well documented but obviously not yet fully understood. It has been explained as an extended range of focus resulting from spherical aberration, small pupil, astigmatic effects and optic travel, to name a few.

Clearly these explanations are not all correct, as some are contradictory and mutually exclusive. While the explanation is still open to question, the phenomenon of pseudoaccommodation is real and reliable, with important practical applications for the lens-based correction of presbyopia. It is a central factor in the outcomes I have described here. Keep in mind that presbyopia is corrected with pseudoaccommodation just as with accommodation. The former is available to us now in implants we have been using for more than a decade.

The art of fully exploiting the pseudoaccommodation inherent in static (nonaccommodating) posterior chamber implants is a significant part of the success of the blended-vision implant approach. If you wonder why you have not heard more about this approach, keep in mind that because there is no specific new IOL technology involved, there is no inherent incentive for industry to promote it. In fact, the opposite is likely the case, so we’ll further discuss the art of applying pseudoaccommodation to presbyopia correction in the November 15 issue.

For Your Information:

William F. Maloney, MD, an associate clinical professor at the University of California, Irvine, and head of Eye Surgery Associates, of Vista, Calif., is a well-known teacher of cataract and lens-based refractive surgery techniques. He can be reached at 2023 West Vista Way, Suite A, Vista, CA 92083; (760) 941-1400; fax: (760) 941-9643; e-mail: williammaloney2000@yahoo.com. Dr. Maloney has no financial interest in any products and has no financial relationship with any ophthalmic company.