PRELEX or Presbyopic Lens Exchanae

A view to the past, present and future

Kevin L. Waltz, OD, MD, and Brenda J. Wahl, OD

Presbyopic lens exchange is a synonym for refractive lens exchange, or RLE. The term refractive lens exchange was popularized by the highly respected Oregon cataract surgeon I. Howard Fine, MD, among others, and is the term preferred by ASCRS.

PRELEX was coined in 2000 by a co-author of this article Kevin Waltz, OD, MD, and popularized by Dr. Waltz and R. Bruce Wallace, MD. Both terms describe the same procedure and are used interchangeably. In some countries, presbyopic lens exchange is the preferred term and in other countries refractive lens exchange is preferred.

Genesis of PRELEX in the United States

In the late 1990s, the popularity and growth rate of then-new LASIK was spectacular. The popularity of LASIK was a phenomenon unlike anything seen before in ophthalmology and affected surgeons' willingness to consider new treatment modalities. It also brought with it new types of patients presenting for treatment — patients with a willingness to consider new surgical options for their vision problems.

Patients with all types of manifest refractions were interested in correction (Figure 1). At the time, the lasers in the United States were only approved for myopic corrections. We had many patients who came to our laser center with hyperopic corrections. Several phakic patients presented to my laser center with manifest refractions of +10.0 or more. Clearly, these patients were not candidates for laser vision correction, but they were desperate for relief from their onerous glasses.

Figure 1. This chart shows that there is an almost equal distribution between myopes and hyperopes in the US, offering many potential patients for Presbyopic Lens Exchange.

Simultaneously, with the peaking in interest in LASIK, the pioneering AMO Array multifocal IOL was approved in late 1997. Coincidentally, Dr. Waltz developed cataracts in late 1997 and had bilateral Array MIOLs implanted in his own eyes in the spring of 1998. The Array MIOLs provided Dr. Waltz with excellent uncorrected distance and near vision in both eyes. Dr. Waltz and others began implanting the Array MIOLs in a rapidly increasing percentage of their cataract surgery patients.

Patients Benefit From a New Procedure

The convergence of the large volume of persistent patients with hyperopic refractions presenting to our laser center combined with the success of the Array MIOL in cataract patients presented an interesting possibility. Dr. Waltz's reasoning in 1999 was this: If a patient presented with aphakia, a +10.0 manifest refraction and visual complaints, that patient would have an IOL implanted without delay.

Was it necessary for a patient to be rendered aphakic before having a suitable IOL implanted, or could a phakic patient with a high hyperopic refractive error have what was essentially a self-paid cataract surgery without having a cataract? At the time, a self-paid cataract surgery without a cataract was commonly called a clear lens extraction.

Clear lens extraction did not enjoy a good reputation among most surgeons in the late 1990s. The lack of enthusiasm was multifactorial. Laser interferometers were not generally available to obtain a very precise axial length. Most surgeons did not have topographers, so the subtleties of the cornea surface were not generally appreciated. The IOL formulas were less accurate.

In addition, there was no mechanism to provide distance and near vision except for monovision. The concept of LASIK enhancement over an IOL was new and not widely trusted. All of these issues conspired to leave a patient with less thick glasses and bifocals after their clear lens extraction. The process was generally not pleasing to patient, surgeon or staff.

The emerging combination of enthusiasm for LASIK by surgeons and patients and a proven multifocal IOL presented a new and unique opportunity. All of the abovestated problems could, in theory, be resolved by a multifocal IOL to provide uncorrected distance and near vision combined with LASIK to resolve any residual refractive error. In this context, presbyopic lens exchange was created.

Genesis of PRELEX in Europe

A few of our European colleagues came to the same conclusions about PRELEX, but years ahead of US surgeons. Our European colleagues had laser vision correction and multifocal IOLs available to them for years prior to US surgeons. The European surgeons combined their experience with multifocal IOLs and laser vision correction and came to the conclusion that implanting a multifocal IOL to reduce dependence on glasses made sense.

Professor Charles Claoué made the first presentation of what subsequently became known as PRELEX at the 1997 ESCRS meeting in Prague: “Do We Already Possess the Technology to Treat Presbyopia?” He presented a hyperopic woman who had become contact lens intolerant and was reluctant to wear glasses. She was successfully implanted with multifocal IOLs to reduce her dependence on glasses. Professor Claoué was confident his patient would do well because he had approximately five years of experience with multifocal IOLs and laser vision correction.

It is fascinating that, presented with the same confluence of technology, European surgeons and US surgeons reached similar conclusions several years apart.

The Beginning: PRELEX Before 2005

PRELEX was more controversial during this time frame than it is today. There was an ongoing discussion within the profession about if it was appropriate to offer this surgery and, if so, to whom could it be safely and effectively offered. Drs. Waltz and Wallace presented a series of courses on the procedure in the United States and Europe. These courses were well attended and there was always a lively debate. They focused on the most current methods to achieve the best results.

The tools to provide PRELEX improved every year and they steadly became more available. The laser interferometer was found to dramatically decrease the variability of axial length measurements for IOL calculations. Therefore, PRELEX experienced dramatic growth during this period. The IOL formulas improved and became better understood by more surgeons. Topographers were shown to be very helpful to evaluate the anterior ocular surface preoperatively and were found in more and more surgeons' offices.

Laser vision correction was FDA-approved to treat both myopic astigmatism and hyperopic astigmatism. It became a more common method to enhance residual refractive errors.

Improved technology and better understanding of the process steadily improved the typical results achieved with PRELEX in the first years of the new century. A side benefit to the efforts required to improve the refractive outcomes of PRELEX was that many surgeons noted the refractive outcomes of their cataract surgeries also improved.

This period was the real beginning of the merger of refractive and cataract surgery. The term refractive cataract surgery was used more and more frequently. PRELEX was essentially the reverse image of refractive cataract surgery. It was essentially elective, preemptive, self-paid cataract surgery held to the very highest standard of refractive outcomes and spectacle independence.

The Present: PRELEX from 2005 to 2012

The year 2005 changed the world of refractive cataract surgery. In 2005, the Center for Medicare and Medicaid Services (CMS) published rule 05-01 that allowed Medicare patients to elect to pay for a presbyopia-correcting IOL.¹

This allowed the surgeon and the facility to cover the additional cost of the lens and the extra services needed to effectively implant it. Before this, the latest models of presbyopia-correcting IOLs, such as the ReZoom, ReSTOR and Crystalens, were not generally available to Medicare patients. This discouraged some surgeons from using these lenses. By creating a clear path to allow a surgeon and facility to charge for presbyopia-correcting IOLs in cataract patients, CMS rule 05-01 was a profound step forward in making these types of lenses available to all surgeons and patients.

This rule was essentially CMS sanctioning the merger of cataract surgery and refractive surgery. It allowed the patient to pay for elective refractive surgery more or less simultaneously with cataract surgery.

CMS rule 05-01 allowed more surgeons to feel the effects, good and bad, of refractive surgery combined with cataract surgery. While the possibility of increased revenue associated with presbyopia-correcting IOLs was attractive, the reality of refractive surgery-level patient expectations in a cataract patient was a significant barrier to increased adoption of presbyopia-correcting IOLs.

Concurrent Growth in Both Procedures

Suddenly, there was not much difference between a wholly elective procedure like PRELEX and refractive cataract surgery with a presbyopia-correcting IOL. The patient was making a significant investment in either procedure and was quite demanding about the return on their investment.

Throughout this time, all of the tools used to achieve a great result with PRELEX continued to improve and the utilization of these lenses continued to increase (Figure 2). The quarterly increase in utilization was incremental, and as surgeons became more comfortable with their results with presbyopia-correcting IOLs, they recommended the lenses to their patients with increasing frequency. The patients' desire for these lenses is evident in the upward trend in the adoption rate. These lenses and the services that go with them are more expensive than cataract surgery with a monofocal lens.

Figure 2. Patient acceptance of “premium” IOLs has been steadily growing in both patient-shared billing and for use in presbyopic lens exchange.

We are not aware of a more consistently, upwardly trending line for a purchased luxury item during the most recent recession and afterward than that of presbyopia-correcting and toric IOLs. We have also noted a steady increase in patients presenting at out practice who are already educated about their lens options and are more than willing to invest in their vision with the understanding that they will receive the value they seek. OM

Reference

1. Centers for Medicare & Medicaid Services Rulings, Ruling No. 05-01. May 3, 2005. Available at: https://www.cms.gov/Regulations-and-Guidance/Guidance/Rulings/Downloads/CMSR0501.pdf. Accessed July 25, 2012.

Kevin L. Waltz, OD, MD, and Brenda Wahl, OD, are in practice at Eye Surgeons of Indiana in Indianapolis. The authors report no financial interest in any of the products mentioned in this article. Dr. Waltz may be reached at KWaltz56@gmail.com.