June 14, 2016
2 min read

Cross-linking will quickly change corneal ectasia management

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American physicist Thomas Kuhn first coined the term “paradigm shift” to describe a fundamental change in how we conceptualize and approach a specific discipline. As eye care providers we are no strangers to this phenomenon. Personally, as I look back over the past few decades, I have certainly seen my share.

I remember the days in which cataract patients were rendered aphakic, soft contact lenses were replaced annually, and glaucoma treatment meant choosing between pilocarpine four times daily or timolol twice daily. While each of these practices was proven and prudent at the time, they were anything but perfect. In the final analysis, it was their shortcomings that drove conceptual change, innovation and evolving practice patterns – in short, a paradigm shift.

Whether considering intraocular lenses, disposable contact lenses or prostaglandin analogs, there is a commonality among paradigm shifts: It is the rather meteoric rise with which things happen. While any new scientific concept is destined to face its share of skepticism and resistance, in general, paradigm shifts seem to gather momentum quickly. Certainly, in the case of the aforementioned examples, it took a mere decade for each to reach a dominant position. If my intuition is correct, we are about to witness another paradigm shift in eye care in the form of corneal collagen cross-linking (CXL).

Michael D. DePaolis, OD, FAAO
Michael D. DePaolis

While lecturing on corneal ectasia recently, I suggested that within the next 5 to 10 years, presentations on this subject will no longer focus primarily on contact lenses. It is not that I believe CXL is destined to eliminate contact lenses in the management of corneal ectasia – quite the contrary. There certainly are plenty of keratoconus, pellucid marginal degeneration and postsurgical ectasia patients to keep specialty contact lens practitioners busy for decades to come. But do we really want to continue diagnosing these conditions relatively late in the game, merely managing visual needs with contact lenses only to then watch patients progress – relentlessly and unpredictably? Do our corneal ectasia patients not deserve better?

It only makes sense that a fundamental change in the way we manage corneal ectasia patients transpires. Essential to this paradigm shift is a strategy by which to halt corneal ectasia progression ... and this is precisely where CXL comes into play. In much the same way atropine and certain contact lens designs have helped us reign in myopia progression, CXL provides us a much-needed tool in the war against corneal ectasia.

How will this paradigm shift play out? It will likely be the result of four factors. First, as in virtually all aspects of eye care, genetics will play a role. With a better understanding of the genetics of conditions such as keratoconus and pellucid marginal degeneration, we will identify at-risk patients sooner. Second, our quest for earlier diagnosis will be fostered by newer technologies. Improved anterior surface topography, full-thickness corneal imaging and corneal elasticity/hysteresis instruments will provide us with diagnostic clues long before patients become symptomatic. Third, I anticipate a more aggressive approach to environmental and lifestyle modification as key in mitigating ectasia progression. Finally, and perhaps most importantly for future generations of corneal ectasia patients, CXL will serve as the main driver of this paradigm shift.

With the FDA’s recent approval of CXL for treating progressive keratoconus – in conjunction with a decade of global experience to draw upon – I anticipate things will move quickly. That being said, the challenges are numerous: Will epi-on or epi-off prevail? Is continuous or pulsed fluence CXL more effective? How will CXL be integrated with PRK and Intacs (AJL Ophthalmic)? Who will perform the procedure?

While it will undoubtedly take time to sort this out, one thing is certain. Our corneal ectasia patients will look to us for guidance, support and answers. Personally, I am looking forward to the challenge, as this is certainly a paradigm shift that is long overdue.

Disclosure: DePaolis reports no relevant financial disclosures.