GOLD STANDARD DELIVERS SATISFACTION AND COMPLIANCE
CLEAR CARE® Cleaning & Disinfecting Solution can help keep patients satisfied in their lenses while helping to promote a healthy lens-wearing experience*
Dr. Epstein: I’m excited to be working with this expert panel on hydrogen peroxide disinfection. As our readers know, contact lens disinfection has been a hot and somewhat controversial topic for the past few years. Following the recall of two major lens care products in 2006 and 2007, we’ve seen a marked increase in the use of hydrogen peroxide disinfection. Our last roundtable exploring this topic received many positive comments from our colleagues. This time, I’d like to focus on some specific areas of clinical concern in even more detail.
So let’s begin with a simple question that should set the stage for the rest of our discussion. Dr. Townsend, you’ve been in practice about as long as I have and your extensive experience with hydrogen peroxide disinfection dates back to its introduction.
Very few of my patients who use CLEAR CARE® Solution have any dryness issues. To the contrary, patients experience excellent comfort using CLEAR CARE®.
— Dr. Townsend
Could you share your perspective on the strengths and weaknesses of peroxide systems in general?
Dr. Townsend: As I see it, the single greatest benefit to patients who use peroxide systems is that they avoid added preservatives. We have hundreds of patients who successfully use multipurpose solutions (MPS) with absolutely no issues. But there’s a segment of the population that develops sensitivity to some component of the MPS, and for these individuals, peroxide systems are very beneficial. Peroxide systems promote compliance because patients who wear soft lenses do not have to rub them.1 CLEAR CARE® Cleaning & Disinfecting Solution also provides very good disinfection.2-5
Peroxide systems don’t have many weaknesses. The most obvious one occurs when a patient inserts a lens soaked in non-neutralized peroxide on their eye. It’s difficult to do so with a system that’s neutralized by a catalyst, but some people manage anyway. Also, if a patient is an “occasional wearer” who infrequently wears and disinfects his lenses, I’m less likely to prescribe peroxide disinfection due to the products’ short storage time.
Dr. Epstein: That’s a great overview. Dr. Chalmers, do you have anything to add?
Dr. Chalmers: Dr. Townsend summed it up nicely. I like that hydrogen peroxide systems have the ability to transform from very active antimicrobial solutions to very biocompatible solutions through the use of catalytic conversion of the peroxide to water and oxygen gas.
Dr. Epstein: I love the way you said that. Essentially, peroxide is a simple, yet elegant disinfection system that works well and, when formulated and used properly, is gentle on the eye. That’s a perfect way to describe peroxide disinfection.
Moving on…CLEAR CARE® has been the gold standard for peroxide disinfection for many years. Dr. Lievens, you have a really busy practice at SCO, so I know you’re proactively looking to minimize problems in your contact lens wearers. I also know you have a high number of complex fits. From a clinical perspective, why do you choose CLEAR CARE®? Which patients do you select CLEAR CARE® for? Is it for every patient?
Dr. Lievens: I choose CLEAR CARE® for contact lens disinfection in my patients who have the most challenges. For example, patients who have sensitivities to added ingredients or preservatives found in other solutions are typical targets for CLEAR CARE®. Additionally, I also select CLEAR CARE® for patients with a particular personality. Patients with type-A personalities are very detail-oriented, so they’re prime candidates. They often love the system and are very diligent and compliant with the steps in the system. I also find that these patients are compliant with return visits and I see them year in and year out.
Dr. Townsend: I touched on this earlier but it’s worth repeating that for individuals who simply won’t follow a rub-and-rinse regimen, CLEAR CARE® is often the best option.
Dr. Brujic: As Dr. Townsend said, CLEAR CARE® also works remarkably well for patients wearing a reusable lens where solution sensitivity is suspected. I also recommend CLEAR CARE® when a wearer is a heavy depositor or has significant seasonal allergies, but isn’t a candidate for daily disposable lenses because of power availability. Finally, I recommend it for gas permeable lens wearers with solution sensitivities or patients who wear piggyback lens designs.
Dr. Epstein: Excellent points. I think you’ve touched on just about everything. I’ll add that many of our colleagues trust CLEAR CARE® more than any other solution.6
Some people describe peroxide disinfection as an old technology, but I see it as proven technology. Many of its early issues, such as case spillage and the risk of forgetting to replace the catalytic disk, have been addressed, particularly with CLEAR CARE® for which a decade of experience has proven its efficacy. Dr. Chalmers, you’ve been involved with CLEAR CARE® for a long time. Can you share your thoughts on this?
Dr. Chalmers: I was part of the hydrogen peroxide disinfection system research and development team that supported AOSEPT® and CLEAR CARE® solutions. I’ve been particularly struck by the improvement in patient comfort with CLEAR CARE® and the low rate of corneal staining, infiltrates7 and papillary conjunctivitis complications associated with its use.8,9 Rather than being old-fashioned, it seems to have stood the test of time, especially compared to some of the lens care failures that caused infectious outbreaks in the past decade.
Dr. Szczotka: Let me add that there’s at least a decade of proven efficacy with CLEAR CARE®. The length of time on the market has allowed it to be assessed epidemiologically in situations of contact lens-related infectious outbreaks. Peroxide systems haven’t been associated with any outbreaks of infectious keratitis.10,11 Additionally, there is virtually no solution-induced corneal staining with CLEAR CARE®, allowing it to serve as a control in studies comparing staining across lens care products.12,13
Dr. Epstein: I think that’s the essence of why CLEAR CARE® is a gold standard for many of us. With its proven disinfection efficacy and its successful use in challenging patients, there’s a reason it has been successful for so long.
Most of us realize that lens care formulations have become quite complex. Attempts have been made to update contact lens care products in tandem with lens materials to enhance comfort, but the unique formulation of CLEAR CARE® Solution continues to offer an excellent option for a wide variety of patients and lens materials. Among them, peroxide is considered a relatively simple and straightforward disinfectant. How important is formulation with a product such as CLEAR CARE®?
I’ve been particularly struck by the improvement in patient comfort with CLEAR CARE® and the low rate of corneal staining, infiltrates and papillary conjunctivitis complications associated with its use. Rather than being old-fashioned, it seems to have stood the test of time.
— Dr. Chalmers
Dr. Townsend: Numerous studies have established that formulation is important, perhaps even critical to the safety and efficacy of any contact lens solution. Multiple past recalls are a reminder that formulation matters. Its patented Triple Action Cleaning formula and the inclusion of its proprietary surfactant make CLEAR CARE® one of a kind. Other peroxide systems are readily available but we have very little information on the precise formulation of these products and there are differences. That’s a concern. Perhaps that’s why CLEAR CARE® is the lens care solution most trusted by eye care practitioners.6
Dr. Epstein: Dr. Chalmers, you have extensive technical experience with the product. Can you share your thoughts?
Dr. Chalmers: The product formulation, its stabilization system and the precision in manufacturing and placement of the catalytic neutralization system are all important components in hydrogen peroxide systems. So, CLEAR CARE® is complicated to make, but fortunately ends up with few chemical agents being carried onto the eye surface with the lens.
Dr. Epstein: That’s very important—perhaps even more so with this product, the proof of the pudding is in the overall design and implementation. It’s easy to overlook those finer points, but it again explains why CLEAR CARE® has been so successful for so many patients for so long.
Let’s focus on the key issues associated with peroxide disinfection—speed of neutralization, effectiveness of kill and I am referring to time kill curves here and let’s contrast that with residual peroxide and the potential discomfort and corneal disruption/staining that can occur when residual levels are too high. Dr. Lievens, this is right up your alley.
Dr. Lievens: Hydrogen peroxide (H2O2) offers many advantages of alternative means of contact lens disinfection. H2O2 actually penetrates the lens matrix and oxidizes foreign matter. 3% H2O2 has been the optimal concentration to kill numerous microbes. Of additional benefit is the ability to break protein to deliver a clean lens inside and out. Of recent note, there’s evidence to demonstrate an improved pre-lens tear film and ocular adnexa with the usage of CLEAR CARE® Solution.8,9 The pre-lens tear film is more stable and the lids are clearer (less papillae and hyperemia) when compared to a multipurpose disinfecting solution. This can be very important as the pre-lens tear film is already challenged with the introduction of a soft contact lens (SCL) and the lid/SCL interaction can cause a multitude of issues when compromised.
Dr. Epstein: Dr. Townsend, can you discuss the fine balance between efficacy and toxicity with peroxide systems?
Dr. Townsend: As we know, hydrogen peroxide kills by directly damaging cell membranes and disrupting genetic material, which disrupts proteins. At a 3% concentration, it kills cells within minutes of exposure. These characteristics make it very efficacious, but also very toxic. It is not selective for bacteria or corneal epithelial cells, so patients must understand that burning, stinging or redness will occur if they unintentionally get unneutralized peroxide in their eyes. For a better understanding of antibiosis of peroxide, I would recommend an article by Linley et al, “Use of hydrogen peroxide as a biocide: new consideration of its mechanisms of biocidal action,” published in the April 2012 issue of the Journal of Antimicrobial Chemotherapy.
Dr. Sindt: I agree. Peroxide is an extremely potent disinfectant. It is very effective at disrupting cell membranes, so it must be neutralized before it comes in contact with the ocular surface. When developing a product, the neutralization curve must be adjusted through the use of stabilizers and buffers to create very low levels of residual peroxide at the end of the soaking cycle. CLEAR CARE® Solution was created with this balance in mind, to formulate a powerful disinfectant, while only having a range of 5-60 ppm residual peroxide at the end of the cycle, (Figure 1) even when the case has been cycled up to 100 times. This is well below the long-established ocular awareness threshold of 100 ppm, so CLEAR CARE® is powerful and safe when used as directed.14-16
Dr. Epstein: Different lens care products require different soak or neutralization times.
What are the advantages of a longer soak time? Are there risks when removing the lenses prior to the end of the indicated neutralization schedule for a product? How do you handle the patient who requests a system with a shorter disinfection/neutralization cycle? Dr. Sindt, what’s your perspective?
Dr. Sindt: With a shorter neutralization time than what’s indicated for the product, there may be higher residual peroxide and a greater risk of stinging, discomfort or outright chemical toxicity.16-18
We know contact lens dropouts due to discomfort can have a financial impact on a practice.24 CLEAR CARE®, however, has the most loyal lens care users of any brand and it has been shown they are highly satisfied with the product.6
— Dr. Epstein
We all understand that lens care does not fit into everyone’s busy schedules, however, there are certain steps that must be taken in order to remain safe and effective. Patients who want a shorter care cycle are excellent candidates for daily disposable lenses. I describe daily disposable lenses as lenses that are ready when they are.
Dr. Epstein: Different strokes for different folks? Actually, I think you’ve just described the essence of the good clinician—finding the best solution for a patient’s needs. And while no one solution is perfect for every patient, CLEAR CARE® Solution has been a problem-solver for me. So, I was a bit surprised by several recent articles generally critical of peroxide that seemed to imply issues with CLEAR CARE®. I also saw a poster at AOA 2012 titled “Issues and Symptoms Experienced While Using Hydrogen Peroxide Solutions” that reported peroxide users are encountering significant discomfort and dryness. I certainly understand that this was a market research survey and was not a scientific work, but I still find this curious since most clinicians recommend CLEAR CARE® for their most sensitive patients. You would think that this potential bias would have been accounted for and disclosed, but patient selection criteria were not reported in this survey. Personally, I’ve seen no comfort issues with CLEAR CARE® when used properly over many years of use and these reports are certainly not representative of the scientific literature, at least what I’ve read. Dr. Townsend, what’s your experience and perspective on this?
Dr. Townsend: Based solely on clinical experience, very few of my patients who use CLEAR CARE® Solution have any lens dryness issues. To the contrary, patients experience excellent comfort using CLEAR CARE®. It has no added preservatives, and so it leaves no irritating residue on lens surfaces or within the polymer matrix,14-16 so contact lenses are left feeling more like new and ocular tissues are not compromised by residual preservative. We know nothing feels better than a fresh, new lens, so it is interesting that a recent retrospective analysis of 28 separate studies of contact lens and lens care combinations showed that users of CLEAR CARE® Solution experience enhanced comfort on insertion and end of day comfort similar to daily disposables (Figure 2).19
Dr. Epstein: Interesting. In fact, in a survey of CLEAR CARE® users, 4 out of 5 respondents agreed that cleaning and disinfecting their lenses with CLEAR CARE® got their lenses so fresh, they felt like new.20 Dr. Szczotka, your thoughts on this?
Dr. Szczotka: A recent BCLA poster showed that CLEAR CARE® Solution was reported to be better tolerated by eyelid tissues when used in conjunction with silicone hydrogel lenses compared to a leading MPS. Less papillae were observed with CLEAR CARE® after three months of use and a decrease in subjective ratings of eyelid hyperemia and papillae compared to use of a habitual PHMB care system were reported, suggesting less inflammation of the eyelids possibly associated with a decreased mechanical interaction.8,9
Also, in a recent clinical trial my group just completed, we did not find differences in CLPC between CLEAR CARE® and MPS users, but there was a significantly higher proportion of MPS participants experiencing superior epithelial arcuate lesions compared to peroxide users (6 vs. 0, respectively; p = 0.03) during 1 year of daily wear with silicone hydrogel lenses.21
I am not aware of any evidence that supports peroxide solutions causing lens discomfort when used as directed. On the contrary, I usually recommend peroxide-based solutions for the most sensitive patients.
Dr. Epstein: Let’s shift gears a bit and look at some of the challenges clinicians face in ensuring patient safety and compliance. Recent publications by the FDA underscore how real-world conditions can negatively impact the efficacy of disinfection systems. Please discuss issues such as compliance, topping off, biofilm formation, the emergence of acanthamoeba as a more commonly encountered pathogen and how CLEAR CARE® Solution addresses these challenges and fits into your clinical armamentarium. Dr. Szczotka, you’ve done extensive research on biofilms. Can you share some of your work and its implications relative to peroxide disinfection?
Dr. Szczotka: Biofilms form rapidly on surfaces within aqueous environments. These microbial communities are made of microorganisms with different genotypes and phenotypes compared to their less pathogenic free-floating (planktonic) forms, which make them much more resistant to disinfection. In the real world, even when cases are replaced regularly, biofilms can form within cases and on lens surfaces. I’ve collaborated with Mahmoud Ghannoum, PhD, and his team at Case Western Reserve University to sort out disinfection capabilities of common MPS and peroxide products against the biofilms formed by bacterial and fungal organisms that are commonly implicated in contact lens infection and inflammation.
I find my patients using CLEAR CARE® return for their yearly visits, and know exactly what they are using lens and disinfection wise and are very involved in their wear. They’re a pleasure to work with.
— Dr. Lievens
In brief, biofilms of Fusarium solani and Fusarium oxysporum were resistant to the antifungal activity of several soft contact lens care products, but the peroxide systems we tested consistently demonstrated effective antifungal activity against both Fusarium strains.3 Biofilms of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus were resistant to commonly used biguanide-preserved multipurpose care solutions but were susceptible to CLEAR CARE®, which was the only peroxide system tested.2
In other publications, researchers have also found disinfection with CLEAR CARE® to be more effective against both trophozoite and cyst forms of Acanthamoeba species than tested MPDSs.4
Lastly, in a large multi-variate analysis, no significant associations were found between peroxide lens care systems and bacterial driven corneal inflammatory events.5
Dr. Epstein: I think it’s important for our readers to understand the critical nature of your work on biofilms. FDA testing has focused on planktonic organisms—essentially individual organisms, but we now know that some pathogens that cause infections in lens wearers are biofilm formers.
I’ll direct this next question to Drs. Sindt and Lievens. You both deal with difficult populations. Have you seen any differences in patient compliance between CLEAR CARE® and conventional MPS and if so, any thoughts on why?
Dr. Sindt: Compliance is a big issue. CLEAR CARE® Solution users are more compliant with lens care practices than MPS users.1 This may be a phenomenon of why they use the product—they switched because of past problems or perhaps the built-in compliance of the system necessitates replacing cases regularly and using fresh solution with each use or stinging will develop.
A study has shown that 42% of MPDS patients top off their solution.21 While noncompliance can still happen with peroxide users, it is to a much lesser extent.
Dr. Lievens: I think the key is in the bubbles. CLEAR CARE® is a H2O2 disinfection system that is very potent. Despite its potency, it also seamlessly neutralizes into a gentle saline solution that is well tolerated. The remaining peroxide is counted in mere parts per million and has been shown in multitude of papers to deliver insignificant ocular effects and an absence of symptoms.5,15-17,23 It is very safe and effective when used as directed. From the patient’s watch, the key is in the bubbles. There’s a visible bubbling reaction when the case-attached platinum disk is inserted into the vial of CLEAR CARE®. The patient can see and hear the chemical action and disinfection. This feedback assists in compliance and not only delivers a clean, comfortable and disinfected lens but the patient perception of all of these as well. This results in a happy and compliant patient.
Dr. Szczotka: Let me add that it’s hard to be noncompliant with CLEAR CARE®. Few patients ever admit to topping off with CLEAR CARE®. They understand and “see” the disinfection step working as the bubbles and gas exchange signal the neutralization cycle.
CLEAR CARE® users also understand the importance of using the correct amount of solution in the lens case because using a smaller amount won’t sufficiently wet the lenses. Lastly, cases with the platinum coated discs are routinely replaced with each purchase of CLEAR CARE®, so patients do not experience burning, stinging, or redness from lack of neutralization due to worn disks in old cases.
Dr. Epstein: All very good points and I completely agree. Unlike MPS products where store brands have been aggressively marketed at major retailers, we’re starting to see similar promotion of store branded activity with peroxide disinfection systems. What are the differences between CLEAR CARE® and store brand peroxide from the clinician’s perspective, and from the patient’s perspective?
Dr. Brujic: Patients have been programmed to think of “generics” as being identical to their name-brand equivalents with the only difference being the labeling and the cost. As clinicians, we understand that these “unbranded” formulas can be much different from their name-brand counterparts.
CLEAR CARE® Solution is unique in its own right. Although we think of CLEAR CARE® as 3% H2O2, it’s truly much more than that with a patented formulation that cannot be duplicated by other peroxide solutions. CLEAR CARE® contains the proprietary Pluronic^ 17R4, which is a unique surfactant that cleans the surface of the lens helping remove protein and debris. Additionally, its unique basket-mounted platinum disk ensures that neutralization of the hydrogen peroxide begins simultaneously with lens insertion into the solution. Store brand products often have their platinum disks located in the bottom of the cup and aren’t attached to the basket that holds the contact lenses. Unfortunately, this creates a potential neutralization process that starts in the absence of contact lenses. So, if the patient doesn’t place the lenses in the basket immediately after pouring solution in the cup, significant amounts of peroxide may be neutralized before the lenses are submerged. Anything that pulls a patient away after the solution has entered the vial, such as getting a phone call, could cause this to occur. This is simply a non-issue with CLEAR CARE® because the case design lends itself to more compliant use. It’s one less concern that we have with CLEAR CARE® when compared to store brand products.
Dr. Epstein: We know contact lens dropouts due to discomfort can have a financial impact on a practice.24 CLEAR CARE®, however, has the most loyal lens care users of any brand and it has been shown they are highly satisfied with the product.6 Why do you think that is? How do you think CLEAR CARE® impacts your patient retention and loyalty? Do you think it makes any difference?
Let me add that there’s at least a decade of proven efficacy with CLEAR CARE®. The length of time on the market has allowed it to be assessed epidemiologically in situations of contact lens-related infectious outbreaks. Peroxide systems haven’t been associated with any outbreaks of infectious keratitis.10,11
— Dr. Szczotka
Dr. Lievens: CLEAR CARE® Solution is simple and easy to use, but the patient must take more care to complete all of the steps compared to multipurpose solutions. The patients to whom I typically recommend CLEAR CARE® have challenges with their contact lens wear already, have been symptomatic SCL wearers or have personalities that I believe will mesh well with this form of disinfection. All of the aforementioned patients are likely to be more careful and diligent contact lens wears. This results in a very loyal consumer base. I find my patients using CLEAR CARE® return for their yearly visits, and know exactly what they are using lens and disinfection wise and are very involved in their wear. They’re a pleasure to work with.
Dr. Brujic: CLEAR CARE® Solution users typically are using the care regimen for a reason. These patients have been educated about the utilization of this product from their eye care professional. We seem to spend more time and emphasis educating CLEAR CARE® users on the wear and care of their lenses with this system and I think that adds to the “loyalty” that we see with this brand. We could actually learn from our time spent educating patients about CLEAR CARE®, which likely directly correlates with how loyal they are and apply it to multipurpose disinfecting solution recommendations. I think that if we placed a fraction of the effort we do when educating our patients on CLEAR CARE® into our MPDS recommendations, we’d likely see a dramatic increase in the compliance of that portion of our lens wearers as well.
Dr. Sindt: Doctors and staff also take the time to explain exactly how to use CLEAR CARE® Solution. They explain why it is different and why the patient should use it. Once the patient experiences the comfort of the product, they become very loyal. The patient understands the benefits and feels the product was selected to meet his specific needs.
Dr. Epstein: How do you think this impacts patient retention and loyalty?
Dr. Brujic: Simply stated, compliant lens care is best for our patients. So whenever we can improve compliance and loyalty, we will improve patient outcomes. Improving outcomes really translates to improving the contact lens-wearing experience. When we accomplish this, we’re much more likely to keep those patients in contact lenses. ■
CLEAR CARE® Solution Still the Gold Standard in Lens Care
Dr. Epstein: I’ve had the good fortune of working closely with Ralph Stone for many years. He’s become a close friend, a generous teacher and mentor, and one of the greatest influences in my professional career. He had a hand in developing almost every currently available lens care product during his long career. Kasey Minick is another of my heroes. He’s among the most notable scientists working in this area and has tremendous experience with peroxide. I had the privilege of talking with both of them about their perspectives on peroxide disinfection.
Dr. Stone, can you discuss the strengths and weaknesses of hydrogen peroxide systems in general?
Dr. Stone: Hydrogen peroxide is often described as having outstanding microbial efficacy and in the end, becomes a gentle saline solution with no added preservatives to prevent toxicity from preservative systems. While this is the objective of the peroxide care systems, it’s only a general perception. Hydrogen peroxide at the currently used 3% or 30,000 ppm concentration is very effective at dealing with most of the organisms that can cause infection during contact lens wear. However, 3% hydrogen peroxide is very irritating and is toxic. Most of us are aware of the result of direct installation. The use of this potent chemical requires neutralization when we use it with contact lenses. How much neutralization is enough? The general opinion in the literature is that it needs go from 30,000 ppm to a concentration of less than 100 ppm before wear. That becomes the weakness of using a hydrogen peroxide system. Neutralization cannot be forgotten or ignored. Compliance is an uncompromising must for successful contact lens wear.
Dr. Epstein: Why were peroxide systems developed?
Dr. Minick: Peroxide systems were originally developed to give practitioners, and patients, a means of disinfecting lenses for patients who’ve been shown to be sensitive to, or have some discomfort or reactivity from, commercial biocides used in many multipurpose lens care solutions. For many practitioners today, this is a key attribute.
Dr. Stone: As a historical note, hydrogen peroxide systems appeared in the late 1970 and early 1980s to move away from heat disinfection and first-generation cold disinfection products that used the biguanide chlorhexidine and the mercury-containing thimerosal. The early peroxide systems allowed us to address the disadvantages of both baked-on deposits from heat, which caused GPC, as well as eliminating allergic reactions resulting from thimerosal and irritation from chlorhexidine.
As we’ve advanced in our technologies, the advantages of an end product with no added preservatives remain a key attribute of hydrogen peroxide systems. The advent of all-in-one multipurpose products in the late 1980s markedly reduced the incidence of allergy-like reactions, but this remains a concern for some patients. Many practitioners have relegated hydrogen peroxide to a problem-solving role when the multipurpose alternative didn’t provide the answer.
Dr. Epstein: Have peroxide systems advanced since their introduction?
Dr. Stone: As we’ve developed one-step multipurpose lens care disinfecting systems with the ability to work with new lens materials, peroxide formulations have added cleaners and wetting agents to provide better comfort. As a category, hydrogen peroxide has remained constant except we’ve lost all of the two-step peroxide systems. Hydrogen peroxide itself has not only disinfecting capabilities but helps in the removal of deposits. Kiel1 showed that a simple peroxide system removes nearly 40% of the protein associated with lenses during a platinum disk disinfection cycle. The addition of a surfactant wetting agent in CLEAR CARE® Cleaning & Disinfecting Solution has made that peroxide system a viable alternative to multipurpose solutions. Hydrogen peroxide remains simple compared to many current multipurpose alternatives that may have multiple disinfectants, cleaners and wetting agents in their formula.
Dr. Minick: It’s funny, but I have to add that the “simple” formulation of CLEAR CARE® Solution is actually quite complex based on the raw materials, engineering of the system and the formulation balance needed to achieve a physiologically acceptable pH and isotonic solution for the patient to safely place the disinfected, clean lenses back into their eyes following neutralization. The addition of the no-rub internal cleaning agent—Pluronic^ 17R4—that Dr. Stone mentioned is proprietary to this product and was added to allow better cleaning and increased buffer capacity to this product over the previous product, AOSEPT® Plus Solution. For this type of a solution, less is better. Less ingredients means a higher chance patients won’t experience problems with the formulation and thus won’t have difficulty wearing their lenses. As a formulator, I see this as a win for both the practitioner and the patient.
Dr. Epstein: Is CLEAR CARE® the Gold Standard for disinfection?
Dr. Minick: When it comes to a peroxide solution, a balanced formulation is very, very important. The raw materials all have to be very high purity and have been screened specifically for use in CLEAR CARE® Solution. From the trusted, high grade hydrogen peroxide to the sodium chloride and phosphates used to make the buffering system in CLEAR CARE®, this formulation is made of the finest quality materials. This attention to quality by the manufacturer assures the quality and stability of this product. This in turn ensures the consumer and practitioner that the patient is getting the same high quality product each time they buy CLEAR CARE®. The formulation is also specially designed to be highly efficacious against bacteria and still give the patient a gentle phosphate buffered saline at the end of neutralization before they put the lenses back into their eyes.
The design of the neutralizing cup and disc is also critical to anti-microbial efficacy. The CLEAR CARE® system was specifically designed with the disc on the lens basket stem, so the solution doesn’t lose peroxide potency. This way the lenses are exposed to the full level of disinfection efficacy of the solution.
The patented formulation of CLEAR CARE® when used with its special cup and disc are shown to keep “end of neutralization” residual peroxide levels in the 5 ppm-60 ppm range over the use of the cup—even up to 100 cycles.2 This designed balance makes CLEAR CARE® very powerful yet gentle on the eye when used as directed. Literature and clinical studies using soaked lenses show this observed level to be safe and within the ocular tolerance level for residual peroxide in the eye, which is usually accepted to be below 100 ppm with soaked lenses. So none of this is as simple as it seems and not all products are the same.
Dr. Epstein: Very nicely stated. More than 20 years ago, I wrote a paper that discussed residual peroxide and variability in innate tear antioxidants so keeping levels as low as possible is important. Formulation differences, soak times and design and age of the case may be important.
Dr. Minick: Absolutely. The eye has catalases in the tear film and ocular tissues, which are the eyes’ natural defense mechanism against peroxide and other free radical systems. The amount of ocular tolerance to a certain chemical such as hydrogen peroxide is usually dependent on the individual and their eye health. Even in healthy individuals the ocular tolerance has been shown to be ~ 250 ppm-300 ppm with peroxide drops instilled directly into the eye before they experience burning and stinging. This ocular tolerance is greatly reduced for soaked lenses to be ~ 100 ppm for hydrogen peroxide and possibly even lower for individuals who might have tear deficiency problems.2 That is why it is so important to try to keep residual peroxide as low as possible so burning and stinging or other discomfort do not arise. Adding extra ingredients to slow down peroxide neutralization in the beginning of the cycle to increase the Area Under the Curve (AUC) for anti-microbial efficacy could result in higher end residual peroxide levels post neutralization. If a patient misuses the product by shortening the soak time, peroxide-based solutions can also result in higher residual peroxide levels because there may not be enough time for complete neutralization of the peroxide to tolerable levels. This could result in more patient complaints about discomfort, burning and stinging.
Dr. Epstein: Do you have anything you would like to add?
Dr. Stone: The hydrogen peroxide systems today all start with 3% hydrogen peroxide and disinfection starts. As the cycle progresses, the concentration decreases until at the end of the cycle, a minimal amount of peroxide remains. Most of the organisms we are concerned with are readily killed by 3% hydrogen peroxide 90 to 99.9% removed in less than 10 minutes.3 The decreasing concentration observed for use of a platinum disk continues to be active although at a slower rate through much of the cycle. Beyond the disinfecting process, it is imperative that the peroxide level be reduced to safe, non-irritating levels. Janoff4 reported that peroxide solution as low as 30 ppm can be irritating dependent on the pH. Tripathi5 reported that in primary epithelial culture even 30 ppm can cause toxic effects on cell. In clinical studies by Paugh and co-workers6 they recommended a residual peroxide of no more than 100 ppm. Even in a recent study by Cavet and co-workers7 data show that toxicity appears somewhere between 85 and 480 ppm. So the design takeaway for these products is the lower the residual peroxide, the better.
Dr. Epstein: We now better understand real world challenges. Where does peroxide fit in?
Dr. Stone: Every disinfecting system has organisms that are more resistant to the ingredients in those products. Today’s testing is designed to evaluate a series of bacteria and fungi, which represent key organisms associated with contact lens infections. All products are effective against these organisms. We can find organisms and strains able to defeat each and every system available including heat and hydrogen peroxide. The efforts are to minimize the risk of infection without causing increased toxicity. With the issues arising from the recalls of 2006 and 2007, new testing procedures have been developed which are undergoing scrutiny by ISO for incorporation into our testing protocols. These tests include the impact of the lens and case in the disinfection process. With hydrogen peroxide the inclusion of the lens and case is not an issue as it is with the disinfecting ingredients currently used in multi-purpose systems. Acanthamoeba has always been a concern and today, depending on the species and strain and testing protocol, the efficacy of products is variable, with many showing activity against the trophozoite form. CLEAR CARE® has always been among the leaders in efficacy against Acanthamoeba.7-9
Dr. Epstein: Recently, some have focused on problems with peroxide. I thought it a bit confusing given my clinical experience. Your thoughts?
Dr. Stone: In the beginning, hydrogen peroxide was developed as an alternative to the more toxic disinfectants—chlorhexidine and thimerosal. As multi-purpose products appeared that were easier to use, many clinicians moved hydrogen peroxide from the first line to a problem solver. We’ve used this for patients with “issues.” By doing, so we shifted the demographic of patients using hydrogen peroxide. In a recent advertorial by Chris Snyder,10 I’m encouraged that when patients with problems of contact lens-related intolerance and discomfort are switched to a hydrogen peroxide care system, they’re often still able to wear lenses successfully. It appears that peroxide systems have resolved issues for nearly 57% of patients who have used a peroxide system. Of the specific symptoms reported, less than 11% (for irritation) are symptoms related to the use of hydrogen peroxide.11 In other research looking at CLEAR CARE® specifically, the persistent foreign body sensation and mechanical irritation—even, in some cases, papillary conjunctivitis—that can come from significant contact lens deposits were often ameliorated by CLEAR CARE®.12,13 In addition, a recent retrospective analysis of 28 separate clinical studies of lens/lens solution combinations involving 3,277 participant months showed that CLEAR CARE® users experienced enhanced comfort on insertion and end-of-day comfort—very similar to daily disposable lenses.14 Given the long history of positive patient and clinician experience with CLEAR CARE® and the volume of data on this product, significant comfort issues seem unlikely when used properly. ■
1. Kiel J. Protein Removal from Soft Contact Lens Using Disinfection/Neutralization with Hydrogen Peroxide/Catalytic Disk. Clinical Therapeutics. 1993;15(1):30-35.
2. Alcon data on file.
3. Janoff LE. Origin and Development of Hydrogen Peroxide Disinfection Systems. The CLAO Journal 1990;16(1):Supplement: S36-S42.
4. Janoff LE. The Effective Disinfection of Soft Contact Lenses Using Hydrogen Peroxide. Contacto. January 1979:37-40.
5. Tripathi BJ, Tripathi RC. Hydrogen Peroxide Damage to Human Corneal Cells In Vitro. Arch Ophthalmol. 1989;107:1516-1619.
6. Paugh JR, Brennan NA, Efron N. Ocular Response to Hydrogen Peroxide. Am. J. Optometry and Physiol. Optics. 1988;65(2):91-98.
7. Mowrey-McKee M, George M. Contact lens solution efficacy against Acanthamoeba castellani. 2007;33(5):211-15.
8. Johnston SP, Sriram R, Qvarnstrom Y, Roy S, Verani J, et al. Resistance of Acanthamoeba Cysts to Disinfection in Multiple Contact Lens Solutions. J Clin Microbiol. 2009;47(7):2040-2045.
9. Szczotka-Flynn LB, Imamura Y, Chandra J, Yu C, Mukherjee P, et al. Increased resistance of contact lens-related bacterial biofilms to antimicrobial activity of soft contact lens care solutions. Cornea. 2009;28(8):918-926.
10. Snyder C. Your Patients Are Not Telling You the Whole Truth. Advertorial sponsored by Bausch and Lomb.
11. Cavet ME, Harrington KL, VanDerMeid KR, et al. Effect of Hydrogen Peroxide Lens Care Solution on Human Corneal Cell Viability and Barrier Function. Poster presented at Global Specialty Lens Symposium 2013.
12. Maissa C, Guillon M, Wong S, Lane A, Patel T, Garofalo R. Silicone hydrogel contact lens effects on eyelid tissues: lens care influence. Poster presented at the British Contact Lens Association annual meeting; June 6-9, 2013; Manchester, UK.
13. Maissa C, Guillon M, Wong S, Lane A, Patel T, Garofalo R. Effect of lens care system on silicone hydrogel contact lens wettability. Poster presented at the Association for Research in Vision and Ophthalmology annual meeting; May 5-9, 2013; Seattle, WA.
14. Diec J, Papas E, Naduvilath T, Xu P, Holden B, Lazon de la Jara P. Combined effect of comfort and adverse events on contact lens performance. Optom Vis Sci. 2013;90(7),674-681.
1. Dumbleton KA, Woods J, Woods CA, Fonn D. Compliance with current contact lens care regimens. American Academy of Optometry Meeting; October 2007.
2. Szczotka-Flynn LB, Imamura Y, Chandra J, et al. Increased resistance of contact lens-related bacterial biofilms to antimicrobial activity of soft contact lens care solutions. Cornea. 2009;28(8):918-926.
3. Retuerto MA, Szczotka-Flynn L, Ho D, Mukherjee P, Ghannoum MA. Efficacy of care solutions against contact lens Fusarium biofilms; Optom Vis Sci. 2012;89(4):382-391.
4. Johnston SP, Sririam R, Qvarnstrom Y, et al. Resistance of Acanthamoeba cysts to disinfection in multiple contact lens solutions. J Clin Microbiol. 2009;47(7):2040-2045.
5. Chalmers RL, Keay L, McNally J, Kern J. Multicenter case-control study of the role of lens materials and care products on the development of corneal infiltrates. Optom Vis Sci. 2012;89(3):316-325.
6. Based on third-party industry report, Alcon data on file 2013.
7. Andrasko G, Ryan K. Corneal staining and comfort observed with traditional and silicone hydrogel lenses and multipurpose solution combinations. Optometry. 2008;79:444-454.
8. Maissa C, Guillon M, Wong S, Lane A, Patel T, Garofalo R. Silicone hydrogel contact lens effects on eyelid tissues: lens care influence. Poster presented at the British Contact Lens Association annual meeting; June 6-9, 2013; Manchester, UK.
9. Maissa C, Guillon M, Wong S, Lane A, Patel T, Garofalo R. Effect of lens care system on silicone hydrogel contact lens wettability. Poster presented at the Association for Research in Vision and Ophthalmology annual meeting; May 5-9, 2013; Seattle, WA.
10. Chang DC, Grant GB, O’Donnell K, et al. Multistate outbreak of Fusarium keratitis associated with use of a contact lens solution. JAMA. 2006;296(8):953-963.
11. Joslin CE, Tu EY, Shoff ME, et al. The association of contact lens solution use and Acanthamoeba keratis. Am J Ophthalmol. 2007; 144(2):169-180.
12. Carnt N, Willcox M, Evans V, et al. Corneal staining: the IER matrix study. Contact Lens Spectrum. 2007;22(9):38-43.
13. Carnt N, Evans V, et al. IER Matrix Update: Adding another silicone hydrogel. Contact Lens Spectrum. 2008;23(3):40-43.
14. Alcon data on file, 2009.
15. SOFTWEAR^ Saline package insert.
16. Paugh JR, Brennan NA, Efron N. Ocular response to hydrogen peroxide. Am J Optom Physiol Opt. 1988;65(2):91-98.
17. Epstein A, Freedman J. Keratitis associated with hydrogen peroxide disinfection in soft contact lens wearers. ICLC. 1990;17:74-81.
18. Tripathi BJ, Tripathi RC. Hydrogen peroxide damage to human corneal epithelial cells in vitro. Implications for contact lens disinfection systems. Arch Ophthalmol 1989;107(10):1516-1519.
19. Diec J, Papas E, Naduvilath T, Xu P, Holden B, Lazon de la Jara P. Combined effect of comfort and adverse events on contact lens performance. Optom Vis Sci. 2013;90(7):674-681.
20. A market research study conducted amongst 107 US contact lens wearers representative of CLEAR CARE® purchasers in the United States, Alcon data on file 2007.
21. Szczotka-Flynn L, Jiang Y, Raghupathy S, et al. Corneal inflammatory events with daily silicone hydrogel lens wear. Optom Vis Sci. 2014;91(1):3-12.
22. Robertson DM, Cavanaugh HD. Non-compliance with contact lens wear and care practices: A comparative analysis. Optom Vis Sci. 2011;88(12):1402-1408.
23. Janoff L. The effective disinfection of soft contact lenses using hydrogen peroxide. Contacto. 1979;21(1):37-40.
24. Rumpakis JMB. New data on contact lens dropouts: an international perspective. Rev Optom. 2010;147(1):37-42.
* Many factors may impact eye health.
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