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Response to multipurpose disinfecting solution article

Issue: April 25, 2013

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To the Editor:

We appreciate the opportunity to respond to the information shared by Neal A. Sher, MD, FACS, Jason Jedlicka, OD, FAAO, and Mikhail Golben (Ocular Surgery News, April 10, 2013, page 36). Since the company’s inception, patient safety has remained Alcon’s highest priority. Introduced in 1998, Opti-Free brand lens care products have been safely and successfully used by more than 60 million contact lens wearers throughout the world. Recent work published by the U.S. Food and Drug Administration underscored the disinfection efficacy of polyquaternium-1 and myristamidopropyl dimethylamine used in Alcon lens care products. In addition, research published by Szczotka-Flynn et al demonstrated the strong efficacy of this disinfection system against biofilm-producing organisms.

All reports of adverse events involving Alcon products undergo thorough medical safety investigation. Alcon also monitors the literature for any reports involving our products. In response to anecdotal reports of infiltrative events with Opti-Free Replenish multipurpose disinfecting solution, Alcon, in 2010, supported a large multicenter, case-controlled retrospective multivariate study, conducted by Robin Chalmers, OD, FAAO. The results were reported in a peer-reviewed paper published in Optometry and Vision Science. This study concluded that no single contact lens, solution or contact lens-solution combination was found to have been associated with a significant increase in the risk of corneal infiltrative events. Notably, this study remains the only peer-reviewed scientific work investigating the occurrence of infiltrative keratitis among contact lens wearers.

The concerns expressed by Sher, Jedlicka and Golben regarding alleged confounding of results due to inclusion of undifferentiated Opti-Free branded products based on market share in the Chalmers study are unsubstantiated and were previously addressed in a response to a letter to the editor submitted by Katz and Schein. In that response, Chalmers and Lisa Keay, PhD, confirmed that the results were unchanged regardless of inclusion or exclusion of unknown Opti-Free branded products.

Reports of infiltrates associated with contact lens wear are neither new nor uncommon. Numerous subsequent reports have clearly established that infiltrates are multifactorial in nature and associated with a multitude of independent inciting factors. The work by Chalmers and colleagues underscores the difficulty in understanding these events, particularly in a limited context.

While we encourage the sharing of clinical information and experience, the anecdotal reports presented by Sher, Jedlicka and Golben (30 cases over 4 years selected for inclusion by the use of Opti-Free Replenish) provide little new or additional information given the numerous potential causes of corneal infiltrates. Beyond the peer-reviewed published work of Chalmers and colleagues, the extensive global use and exceptional safety record of Opti-Free Replenish do not corroborate the experience or conclusions of Sher, Jedlicka and Golben.

Alcon takes any reported issues with our products very seriously. We have extensive quality control mechanisms and safety processes in place to ensure the safety and performance of our products. We appreciate the trust that both patients and practitioners place in our company and our products.

Peter Bergenske, OD, FAAO
Director Professional & Clinical Support, Alcon

References:

• Chalmers RL, et al. Optom Vis Sci. 2012;doi: 10.1097/OPX.0b013e318240c7ff.
• Chalmers RL, et al. Optom Vis Sci. 2013;doi: 10.1097/OPX.0b013e3182851d92.
• Shoff ME, et al. Eye Contact Lens. 2012;doi: 10.1097/ICL.0b013e31826f0fdb.
• Szczotka-Flynn LB, et al. Cornea. 2009;doi: 10.1097/ICO.0b013e3181a81835.

The authors respond:

We appreciate Dr. Bergenske’s response to our article describing infiltrative events seen with Opti-Free Replenish and agree that patient safety is the highest priority. We have chosen to present these cases to alert other practitioners to the infiltrate problem associated with Opti-Free Replenish and to encourage the reporting of these cases to manufacturers and governmental authorities. Since our initial report, other clinicians have contacted us with similar observations. There are several points brought up by Dr. Bergenske that deserve comment.

The disinfection efficacy of polyquaternium-1 and myristamidopropyl dimethylamine multipurpose solution is open to discussion. Dr. Bergenske’s position ignores the study published by Wilcox in Optometry and Vision Science that used simple culturing techniques to demonstrate that Opti-Free Replenish was relatively ineffective in comparison to Opti-Free Express based on lens case contamination after only 1 month of normal use. Specifically, Opti-Free Replenish allowed the growth of gram-negative bacteria, particularly Delftia acidovorans (63,244 microbes for Opti-Free Replenish vs. 223 for Opti-Free Express). Other investigators, such as Kilvington and Shovlin, have also found a problem with gram-negative bacteria in the cases and lenses of patients using Opti-Free Replenish. It is important to consider all the disinfection efficacy data in the literature, but in the case of corneal infiltrative events, efficacy against gram-negative species is particularly important.

Dr. Bergenske cites the Chalmers study from 2010 that Alcon helped design and coauthor. The study was designed to exclude patients with mild symptoms or who presented for routine care and were found to have asymptomatic infiltrates that we have more commonly seen. The lumping of Opti-Free Express and Opti-Free Replenish makes the study’s conclusions questionable. In fact, 32% of the corneal infiltrative event cases in the Chalmers study did not accurately identify or were missing which lens care solution was used by the patient.

We agree with the criticisms of this article in the letter published by two leading experts from Johns Hopkins, Joanne Katz, ScD, a biostatistician, and Oliver Schein, MD, MPH, a corneal and contact lens expert at Wilmer Eye Institute. They questioned the inclusion of microbial keratitis, acute red eye, solution hypersensitivity, superior epithelial arcuate lesions, vial keratoconjunctivitis, contact lens peripheral ulcer and asymptomatic infectious keratitis in the case definition of corneal infiltrative events. It is a worthy goal to look at all these conditions, but this dilution of the case definitions makes it more difficult to find a true association with the entity we are seeing, contact lens-associated infiltrative keratitis. Of more significance is Katz and Schein’s conclusion that the Chalmers study was grossly underpowered and needed a much larger sample size to be considered definitive.

The Chalmers study is subject to similar confounding errors as retrospective studies like ours and the many others that have been published or presented showing the same pattern of association of corneal infiltrative events with Opti-Free Replenish. We disagree with the assertion that the Chalmers study is the only peer-reviewed study of infiltrative keratitis in contact lens wearers. This is false. The excellent study by Carnt et al in Archives of Ophthalmology has demonstrated corneal infiltrative events in contact lens wearers, predominantly associated with Opti-Free Replenish.

We again thank Dr. Bergenske for his comments and hope that our experience will help further elucidate this problem and stimulate further reporting of adverse events and research to eliminate any potential harm to our patients.

Neal A. Sher, MD, FACS, Jason Jedlicka, OD, FAAO, and Mikhail Golben
Minneapolis