The Debate Rages On
The Debate Rages On
BY JASON J. NICHOLS, OD, MPH, PHD, FAAO
It's unlikely that you've missed the many publications, editorials or lectures on corneal staining associated with contact lenses and care solutions. Debate surrounds the idea that certain care solutions can induce corneal staining. In this regard, research has shown that some care solutions can be associated with the induction of corneal staining on a short-term basis. Yet, other research has shown that other care solutions can be associated with more frequent corneal staining over a longer-term basis. There has even been some research demonstrating that certain contact lens materials can be associated with increased corneal staining even in the absence of a contact lens care system.
In all of this debate, it is critical that we not lose sight of some fundamental questions that remain unanswered. First, regardless of the cause of corneal staining, what is the clinical significance of it and when, if ever, does it pose a risk to our patients? What specifically is that risk — infection, inflammation? Likewise, if we do assume that there is risk to our patients with some level of corneal staining, what is that critical threshold? Beyond safety issues, another important consideration is comfort. The relationship between comfort and corneal staining is important to consider, particularly for regulatory agencies when considering clinical trial end-points. Some population-based studies have failed to show a correlation between corneal staining and patient symptoms, while other studies may indicate a relationship when a specific question is asked.
Lastly, is a "solution" needed and what is it? Research seems to show a trend of reduced staining with the use of hydrogen peroxide-based systems, although clearly these are not without problems. Likewise, daily disposable lenses present a potential strategy, given that they don't require a care solution. However, the United States market has yet to embrace this modality to the same extent as other parts of the world.
Clearly, there are numerous unanswered questions associated with this topic. As we noted in our year-end communications, we've made some editorial changes in the journal that should spark some interesting discussions. In this month's issue, we unveil a new department called Point/Counterpoint in which we have two respected, expert clinician-scientists address a timely issue selected by our editorial staff. In its inaugural printing, we've asked Drs. Lyndon Jones and Phil Morgan to tackle the issue of corneal staining head on (see Point/Counterpoint article of this issue). We hope you enjoy this new format and the future topics and debate to come.
Contact Lens Spectrum, Issue: February 2009