Article Date: 4/1/2002

Solution Comparison
A Comparison of Multi-purpose Care Systems
A study compares patient dryness and discomfort symptoms found with MPS and a one-bottle peroxide system.
Sally M. Dillehay, OD, MS, FAAO; Heather E. McCarter, BA, and the AOSept Clear Care Study Group

The most often cited reasons for drop out or discontinuation of soft contact lens wear are discomfort and dryness. Several recent clinical studies have indicated that multi-purpose soft contact lens solutions (MPS) cause increased symptoms of dryness and discomfort. These increased symptoms of dryness and discomfort with MPS have been referred to as multi-purpose "non-keratitis." This term has been suggested because these patients clinically show all the signs of having adequate tear levels, yet they complain of feelings of dryness and discomfort when wearing their contact lenses.

A new disinfection product recently launched by CIBA Vision, AOSept Clear Care, is a one-bottle, no-rub solution that uses hydrogen peroxide as the disinfecting agent. Because AOSept Clear Care has no added MPS preservatives, this clinical study was undertaken to see if AOSept Clear Care helped to reduce or eliminate patients' symptoms of dryness or discomfort experienced with MPS products.

Figure 1. Subjects' current MPS brand at enrollment.

Study Design

This study was a single-masked, open-label, multi-center study, and was completed at 18 eye care offices throughout the United States. To reduce bias in the results, patients were masked by not disclosing the name of the sponsor to them. A total of 148 patients were enrolled in the study (114 females and 34 males). The average patient age was 35.58 + 10.38 years (range 18 to 70 years). Of the 148 patients enrolled, 140 completed. Four patients were discontinued due to discomfort, and four patients were discontinued due to a missed visit.

To participate in the study, patients had to be current daily wear, soft contact lens wearers who replaced their lenses every two weeks, had worn soft lenses for at least one year and had used a currently available MPS care system for at least one year. Patients completed a questionnaire concerning the frequency and intensity of dryness symptoms, comfort and vision with their lenses and current MPS care system. The practitioner completed detailed vision, slit lamp and tear film examinations.

Each patient was then dispensed a one-month's supply of AOSept Clear Care and scheduled for a return visit in one month. Patients continued to wear their same contact lenses and were instructed to follow their normal lens replacement schedule throughout the study period. At the second visit, the patients again completed the subjective questionnaire rating the frequency and intensity of dryness, comfort and vision with their lenses while using AOSept Clear Care for the past month. The visual, slit lamp and tear film evaluations were repeated. Patients were also asked to specify whether they preferred their regular lens care brand or the lens care brand used in this study.

Figure 2. Subjects' current contact lens brand at enrollment.

Methods

Using a patient-completed survey, several different symptoms were evaluated. The frequency of dryness symptoms were evaluated using a scale of 1 to 4 where 1=never, 2=some days, 3=most days, and 4=everyday. The scale for intensity was: 0=none, 1=slight, 2=mild, 3=moderate, and 4=severe.

In terms of specific symptoms experienced with patients' previous multi-purpose care system as compared to AOSept Clear Care, symptoms such as burning/stinging, itchiness/scratchiness, lens awareness, redness, irritation/discomfort and cloudy/blurry/ hazy/variable vision were all investigated.

For those patients indicating they did experience a specific symptom, they evaluated both the frequency and severity of each symptom. The scale used for frequency was 1= rarely, 2=occasionally, 3=often, 4=constantly. The scale used for severity of each symptom was 1=very little, 2=mild, 3=moderate, and 4=severe.

The evaluation scale used for overall comfort was 1=poor, 2=fair, 3=satisfactory, 4=good, and 5=excellent, and the evaluation scale used for overall vision was 1=poor, 2=fair, 3=satisfactory, 4=good, and 5=excellent.

Figure 3. Subjects' dryness frequency during the day.

Results

Previous MPS Brand For the 148 patients enrolled in this study, their lens care brands at enrollment were as follows and are shown in Figure 1: Opti-Free=62, ReNu=52, Solo-care=9, Complete=13, other brands=12. The average length of time for using their current multi-purpose solution was 4.0 ± 3.4 years. Some 4.7 percent of the patients enrolled reported using enzymatic cleaners with their lenses.

Contact Lens Brand The contact lens brands worn by study patients are shown in Figure 2. The average duration of having worn contact lenses was 9.36 ± 7.35 years for patients enrolled in the study.

Frequency of Dryness Symptoms A comparison between the frequency of dryness symptoms with their MPS lens care brand at enrollment and AOSept Clear Care is shown in Figure 3 for symptoms experienced during the day, and Figure 4 for the end of the day.

The average value for dryness frequency during the day with MPS was 2.05 ± 0.83 and 1.63 ± 0.76 for AOSept Clear Care. The average value for dryness frequency at the end of the day with MPS was 2.39 ± 0.94 and 1.94 ± 0.90 for AOSept Clear Care. These findings were statistically significant (p¾ 0.001 for during the day and p¾ 0.001 for the end of the day, two-tailed t-test), indicating that patients experienced dryness symptoms significantly less often when using AOSept Clear Care, both during the day and at the end of the day.

Intensity of Dryness Symptoms A comparison of the intensity of dryness symptoms between their previous lens care brand and AOSept Clear Care is shown in Figure 5 for during the day and Figure 6 for at the end of the day.

Figure 4. Subjects' dryness frequency at the end of the day.

The average values for dryness intensity during the day with MPS was 1.46 ± 1.10 and 0.81 ± 1.01 for AOSept Clear Care. The average values for dryness intensity at the end of the day with MPS was 2.02 ± 1.30 and 1.23 ± 1.15 for AOSept Clear Care. These average findings were statistically significant (p¾ 0.001 for during the day and p¾ 0.001 for the end of the day, two-tailed t-test), indicating that patients experienced significantly decreased severity of dryness symptoms with AOSept Clear Care both during the day and at the end of the day.

Interestingly, more than 43 percent of the patients stated they experienced moderate to severe dryness symptoms at the end of the day when using their MPS, even though patients enrolled in the study were not believed to be having any problems with their current MPS system.

Frequency and Intensity of Specific Ocular Symptoms A Wilcox-paired test was conducted in order to analyze both the number of patients experiencing each symptom and when it occurred, how frequent or severe it was, with MPS as compared to AOSept Clear Care. The symptoms analyzed included burning/stinging, itchiness/scratchiness, lens awareness, redness, irritation/discomfort, and cloudy/blurry/hazy or variable vision.

The results of the Wilcox-paired test showed that for all of these symptoms investigated, patients in this study experienced statistically significantly fewer symptoms with less frequency and less severity with AOSept Clear Care as compared to MPS (p¾0.001).

Figure 5. Subjects' dryness intensity during the day.

Overall Comfort Overall comfort with patients' lenses was compared and is shown in Figure 7. Overall comfort of patients' lenses while using their multi-purpose solution was 4.01 ± 0.82, and 4.26 ± 0.84 with AOSept Clear Care. This difference in comfort was statistically significant (p¾ 0.01, two-tailed t-test).

Overall Vision Overall vision with patients' lenses was compared and is shown in Figure 8. Overall vision with their lenses while using a multi-purpose solution was 4.16 ± 0.70, and 4.33 ± 0.77 with AOSept Clear Care. This difference in vision was statistically significant (p¾ 0.05).

Wearing Time The majority of patients in this study were long-time contact lens wearers, as shown by the average number of years wearing contact lenses to be 9.36 ± 7.35 years. Therefore, most of these patients were at a near maximum wearing time per day and days per week, with an average wearing time of 6.49 ± 0.94 days per week and 13.11 ± 2.56 hours per day. Still, 29.3 percent of people reported wanting to wear their lenses longer when using their MPS. Some 46.0 percent reported being able to actually wear their lenses longer when using AOSept Clear Care as compared to their MPS.

Figure 6. Subjects' dryness intensity at the end of the day.

Lens Care Preference

Overall, out of 140 patients completing the study, 113 (80.7 percent) patients preferred AOSept Clear Care over their multi-purpose lens care system, as shown in Figure 9. Many patients commented specifically about how much cleaner, more comfortable or less dry their lenses seemed when using AOSept Clear Care.

The preference for AOSept Clear Care is shown in Figure 10 as compared specifically to the patients' previous MPS systems.

The preference for AOSept Clear Care is shown in Figure 11 broken down by the patient's contact lens brand.

Dry Eye Patients

At enrollment, patients were asked, "Do you have dry eyes?" This question was included in the survey based on a previous report that asking patients if they think they have dry eyes is one of the simplest predictors that a patient does indeed have symptoms of dryness severe enough to be indicative of dry eye. Some thirty-seven patients identified themselves as having severe enough symptoms of dryness that they considered themselves as having dry eyes. For these patients, 30 of them (81.1 percent) found that AOSept Clear Care decreased their symptoms of dryness in either frequency, intensity, or both. Some 33 of these 37 self-perceived dry eye patients (89.2 percent) preferred AOSept Clear Care over their current multi-purpose solution.

Figure 7. Overall comfort of contact lenses.

Allergy Patients

At enrollment, patients were asked if they had any allergies. Some 54 patients identified themselves as having allergies. The allergies listed included: seasonal (33 patients), pollen (6 patients), hay fever (10 patients) and other types (18 patients). Some patients expressed having more than one type of allergy.

For those self-identified allergy patients, 40 of them (74.1 percent) found that AOSept Clear Care decreased their symptoms of dryness in either frequency, intensity, or both. Some 43 of these 54 self-identified allergy patients (79.6 percent) preferred AOSept Clear Care over their current multi-purpose solution.

Separate Rinse Solution

Some practitioners have expressed a concern that AOSept Clear Care does not include a separate solution for rinsing lenses. Since AOSept Clear Care is hydrogen peroxide (H2O2) based, their concern was that a patient might accidentally use unneutralized H2O2 to rinse their lenses. In this study, approximately 4,346 uses of AOSept Clear Care occurred. There were only two reported cases where un- neutralized H2O2 was put directly in the eye by a patient which represents only 0.046 percent of the total times the product was used in the study.

Figure 8. Overall vision with contact lenses.

Discussion

The patient preference rate of 80.7 percent overall for AOSept Clear Care, 89.2 percent for self-perceived dry eye patients and 79.6 percent for self-reported allergy patients is a favorable indication that the elimination of multi-purpose solution preservatives can greatly increase a patient's comfort with his contact lenses. The fact that AOSept Clear Care was preferred over every single multi-purpose solution used by patients in this study, and nearly every multi-purpose solution currently on the market, is intriguing since the multi-purpose solutions each have different formulations. This finding suggests that multi-purpose solutions as a category may have so many added ingredients that they may tend to disrupt the delicate balance of the ocular surface and eventually lead to symptoms of dryness and discomfort.

Is it possible that the improvement in dryness or discomfort ratings seen in this study were due to a placebo effect, i.e., patients felt that their symptoms had improved solely because they were using a new lens care system? First, it is generally very difficult to get patients in comparative studies to choose something other than their current product. This difficulty may be due to a "if it ain't broken, don't fix it" mentality. Patients are creatures of habit, and especially if they have been using a product for some time, they are reluctant to change unless they experience a true benefit with the new product.

Figure 9. Subjects' overall lens care preference .

Second, the one month length of the study, would be long enough that it would negate a possible placebo effect. After one month, patients would have been able to tell if the product was truly not making a difference.

Third, if the preference for AOSept Clear care was due mainly to a placebo effect, it should have been much closer to 50 percent, indicating a random preference, rather then the 80 to 89 percent preference levels seen in this study.

Fourth, in other longer term studies, which used a randomized, cross-over comparison design for AOSept Clear Care to MPS, similar preference rates and improvements in symptoms of dryness and discomfort were also found, even though this study design would have minimized any potential placebo effect.

Fifth, the consistency in the data between decreased intensity and frequency of all investigated symptoms, increased comfort ratings and the overall preference data for AOSept Clear Care strongly suggests that the impact of a placebo effect on this study was very minimal, and that patients preferred AOSept Clear Care because it truly improved their comfort or decreased their symptoms.

Figure 10. Subjects' overall lens care preference by MPS brand.

Because AOSept Clear Care was preferred with and decreased significantly the dryness and discomfort symptoms seen with all of the major two-week replacement contact lens brands currently on the market, this also suggests that practitioners who encounter patients with symptoms of contact lens dryness or discomfort should consider first changing these patients to AOSept Clear Care rather than changing the contact lens brand or contact lens material.

The patients recruited for this study were not patients identified by their practitioners as having problems. The patients in this study were everyday, current contact lens patients who their practitioners felt were doing fine with their current contact lenses and multi-purpose solutions. Yet when completing the survey, 85.7 percent of these patients using a multi-purpose solution described having at least mild or occasional symptoms or greater of dryness and discomfort, and 50 percent of the patients reported having either moderate, severe or highly frequent symptoms. Additionally, 76.7 percent of these patients having symptoms of dryness or discomfort achieved increased comfort or decreased symptoms by eliminating the multi-purpose solution and using AOSept Clear Care.

Summary and Conclusion

Practitioners should re-examine their contact lens care recommendations and carefully evaluate how the elimination of multi-purpose lens care solutions could impact their contact lens practices. Generally, AOSept Clear Care was shown by this study to improve contact lens patient comfort regardless of which multi-purpose solution brand or contact lens brand a patient was currently using. Perhaps the reason that dryness and discomfort are the top reasons for contact lens dropouts is due to the high penetration of multi-purpose solutions in the marketplace.

 

Figure 11. Subjects' overall lens care preference by contact lens brand.

 

This study was funded by CIBA Vision.

The AOSept Clear Care Study Group includes: Jill S. Anderson, OD; Richard Centar, OD; Garry T. Chrycy, OD, FAAO; Sander S. Dorfzaun, OD; Ella Goldberg; David Grosswald, OD; Kenji Hamada, OD; Jane Lindell Hughes, MD, FACS; Michael J. Johnson, OD; James W. Kershaw, OD; Renny Knowlton, OD; Michael P. Lange, OD; Wilson Movic, OD; Rhonda Mullen, COT, FCLSA; Rod Rallo, OD; Jeffrey Schultz, OD, MS, FAAO; Barbara Smith, COA, NCLE; Christine W. Sindt, OD; Ronald Watanabe, OD; Frank H. Yoon, OD

References are available upon request. To obtain references via fax, call (800) 239-4684 and request document #81. (Have a fax number ready.)

Dr. Dillehay is the head of Academic Development at CIBA Vision.

Ms. McCarter is a research project assistant at CIBA Vision.

 


Contact Lens Spectrum, Issue: April 2002