Refractive lens surgery comes of age as Ridley’s IOL revolution enters phase 2

The broad refractive potential of the IOL is now being realized by many surgeons.

Issue: April 1, 2004

ByWilliam F. Maloney, MD

This spotlight section is dedicated to refractive lens surgery, and I have been asked to contribute some thoughts on the lens-based approach to vision correction. I have chosen to focus of the big picture rather than the details of specific techniques because the big picture is the way I see trends best. This broad-brush perspective gives me the best fix on the trajectory of our present pathway and thus a possible clue to its next destination. For the more detailed approach and specific techniques, I hope that you will visit our regular column, which will appear in our next issue.

I want to start by recounting a brief conversation I had with Howard Fine. I believe the year was 1994. We were discussing PRK and LASIK, which had recently begun to generate interest. We regularly taught together, and after many similar discussions on other issues, Howard had come to know of my penchant for the big picture, and our conversation turned to LASIK and the IOL. “Which do you think it will be in the end? Which will dominate refractive surgery?” Howard asked. “The IOL is a major technological breakthrough,” I said. “I think its refractive potential is too compelling for it to be limited to cataract surgery. In the end, I think that we’ll see the IOL carry the heavy load in vision correction.” Without hesitation, Howard concurred.

I never forgot that conversation, but I had assumed that Howard did, until a recent Ocular Surgery News roundtable discussion in which we both participated, along with Bruce Wallace. The topic was refractive lens exchange (RLE). In the course of our discussion, Howard referred to that same conversation from 10 years earlier. As it turned out, that conversation had registered permanently for both of us, and it guided us like a laser beam to RLE and other applications of refractive lens surgery.

Refractive potential of the IOL

A decade earlier, both of us had been able to see the refractive potential of the IOL. We shared a common view of the future shaped by that insight. It was as if we were together driving an unfamiliar road at night unsure of what was up ahead, and then the headlight brights clicked on. Suddenly we could see further, and we knew what lay ahead. The bright lights are clicking on everywhere now. Having completely transformed cataract surgery during phase 1 of Ridley’s revolution, the IOL is now increasingly seen for what it has always been — not merely a replacement for cataract but the most effective vision correction tool at our disposal. It was there all along, only it was just beyond the reach of our vision until the brights clicked on. This is a metaphor for a classic paradigm shift, which I have written about before.

The paradigm shift

In his text “The Structure of Scientific Revolutions,” Thomas Kuhn’s familiar phrase, paradigm shift, was first used to describe the process by which progress takes place within a particular scientific community (ophthalmology in our case). Gifted individuals who are able to see what lies ahead sooner than the rest introduce an innovation into the community. These visionaries are endowed with permanent brights, if you will. Thereafter, subsequent innovations will be seen as an advance only by those equipped with this new broader prospective, the new paradigm. Our paradigms are the organizing principles by which we parse or structure our world. Those concepts that make sense to us are only those that are consistent with and advance our paradigm. An innovation that is inconsistent with our paradigm is immediately discounted as irrelevant.

Kuhn thus described the conflict between the visionaries and the established authorities not so much as a turf war but rather as a communications problem. Individuals holding to different paradigms within the same scientific community literally cannot communicate as they have no common reference. What is deeply real for one is not yet in existence for the other. They are as two people comparing a hidden image sketch where only one sees the hidden image. The one who sees it is attempting the impossible — to convince the other of a reality not yet real for him. It is not yet within the range of his perspective or headlights. No amount of persuasion can help. Either you see it or you do not.

But then in a gestalt-like instant, his brights click on, and the hidden image suddenly leaps into view. In that moment, the paradigm has shifted for yet another member of the community. He sees it now. Dumbfounded that he could not see it just an instant before, he shares his newfound insight with another colleague and attempts to convert him. Soon, when a sufficient number of individuals have seen it, the tipping point occurs, and the community as a whole adopts the new paradigm, which becomes the new organizing principle for yet another generation of innovations.

Kuhn’s theory is extremely useful. It reminds us that change is inevitable by showing the mechanism by which it occurs. It loosens our grasp on what we want to take for a permanent reality. It is the tough lesson we need to keep our gaze on the future, not the familiar present. Apply it to physics, for example, and watch Newton’s universal theory of planetary motion (gravity) as it is rudely shoved aside by Einstein’s theory of relativity. But right now, let us return to Ridley’s revolution and look at it within the context of one of our own paradigms.

Ridley, phase 1

Phase 1 of Ridley’s IOL revolution virtually reinvented cataract surgery within the span of 50 years. During that time, the cataract surgery paradigm shifted, slowly at first and then very rapidly within the last decade, from a solely extractive procedure to a refractive procedure for both hyperopic and myopic cataract patients. Today, there is no practitioner in the developed world who is unaware of the refractive paradigm for cataract surgery.

As the paradigm shifted, potential refractive benefits became an increasingly important consideration for cataract surgery. Innovations in the field of cataract surgery were increasingly directed toward improving the refractive results of cataract surgery. The search for an astigmatically neutral incision, astigmatic keratotomy and improved IOL calculation formulas are all early examples. None of these innovations would have made sense to an individual who could not yet see the new refractive paradigm for cataract surgery. More recently, immersion A-scans, the IOLMaster for more accurate spherical refractive correction and multifocal IOLs or blended vision implants for presbyopia have all greatly enhanced the corrective capability of cataract surgery. As these refractive improvements took hold, the threshold of obstructive visual impairment necessary to recommend cataract surgery dropped dramatically for the many patients with a significant refractive visual impairment. The very reasons for performing cataract surgery were altered by the new refractive paradigm.

By the end of phase 1, Ridley’s IOL revolution had brought us to refractive cataract surgery — the name reflecting the increasing emphasis on its powerful corrective capabilities. As these capabilities were increasingly applied, it was inevitable that cataract surgery would move closer and closer to the 20/20 threshold, beyond which is our topic here today, refractive lens surgery and a new paradigm.

Ridley, phase 2

What Ridley saw 50 years ago and Kelman saw 35 years ago, Howard, I and many others have begun to see within the past 10 years. The trajectory of that pathway has brought us to refractive cataract surgery. The next flagstone on our path is now in clear view as the brights click on all around us. It is now one small step from refractive cataract surgery across the 20/20 threshold to refractive lens surgery. That is our next step. Either you see that or you do not (yet).

Cataract as we have known it is about to be removed from the equation as the paradigm is shifting to the lens. This is happening in part because of a significant redefinition of visual impairment from Snellen acuity standards to more subjective criteria based upon lenticular aberrations. The traditional opacified cataract is increasingly seen as the end stage of a series of lens changes that will be addressed much earlier in order to eliminate the aberrations but more so to realize the vision correction that accompanies removal of that lens, in particular presbyopia.

The tipping point has been reached, and innovations that advance this new paradigm will line up on our horizon waiting to be applied. The change in visual standards is one such innovation. The accommodating IOL is another, as is the phakic IOL. As all these innovations seek our acceptance, it is crucial that we remember our role as physicians in this process. It is our responsibility to separate the science from the salesmanship. It is up to us to withhold our acceptance of any particular innovation until we are certain that it advances the paradigm without harming our patients.

One giant leap

Finally, I want to emphasize something that I have mentioned before. That small step across the 20/20 threshold is a giant leap in terms of the demands placed upon the surgeon to consistently achieve the necessary refractive results without complications. When the cataract is removed from the clinical picture and the only reason for surgery is vision correction, that vision must be corrected to the patient’s full satisfaction. This requires careful alignment of patient expectations and a thorough understanding of the patient’s lifestyle and visual needs.

This aspect of refractive lens surgery is an art, and it requires significantly more chair time than cataract surgery typically does. Learn this art by treating every cataract patient who expresses interest in vision correction as a RLE. These patients are typically willing to pay for the uncovered services involved such as corneal topography, astigmatic keratotomy and any other service designed solely to eliminate glasses. Patients who do not elect this custom vision cataract surgery are informed of the likelihood that they will have some need for glasses after their surgery. This eliminates the problem of the unspoken assumption that routine cataract surgery automatically eliminates glasses. (Click here to read guidelines on the proper billing procedure. An article by Kevin Corcoran in the June 1, 2003, issue.)

As the IOL assumes its rightful place in the refractive arena, surgical skills become increasingly important. State-of-the-art skills are now more important than ever. This is as it should be because regardless of how clearly we see the new paradigm and regardless of how promising the new technology, the success of the surgery can never be separated from the surgeon.

For Your Information:

William F. Maloney, MD, 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.