A Clinical Comparison of Lens Care Systems for Soft Contact Lenses

BY THOR MAGNE SELAND & JENS KRYGER, OPTOMETRISTS
JAN. 1997

In this study, conducted at the Seland Optikk Clinic in Norway, patients preferred the Pure Eyes hydrogen peroxide lens care system 3 to 1 over their previous systems.

Eighty-nine patients wearing soft contact lenses in a monthly replacement program and using either ReNu or Opti-Free multipurpose lens care systems, participated in this one-month study. We dispensed new lenses and placed the patients on Pure Eyes, a multipurpose disinfection system. The majority of patients preferred the Pure Eyes system over their previous lens care system, and their lenses showed fewer deposits.

METHODS

Study participants included 61 women and 28 men between the ages of 15 and 35. Fifty-three patients wore Focus, 29 wore Surevue, six wore Medalist, and one wore 'other' lenses. Sixty-six patients used ReNu and 23 used Opti-Free multipurpose solutions.

At the initial study visit, we performed slit lamp examinations and questioned patients about their current lens care system. We asked the patients how often they rubbed and rinsed their lenses (never, seldom, once a week, 2 to 3 times a week or every day) and how they would grade their overall satisfaction with the current care system with respect to ease of use, lens insertion comfort and overall lens comfort on a scale from 1 to 10, where 1 is very poor and 10 very good.

Slit lamp examination included observation of epithelial integrity, corneal infiltrates, microcysts, corneal vascularization and conjunctival hyperemia. We graded these findings according to the Cornea and Contact Lens Research Unit (CCLRU) Standards for Success of Daily and Extended Wear Contact Lenses. We inspected the lenses while on the eye and noted deposit type as none, lipid, protein or both. We graded deposit amount as none-0, slight-1, moderate-2 or heavy-3.

Overall Preference

We then dispensed a new pair of their habitual soft contact lenses to the patients and gave them a one-month supply of the Pure Eyes system on open label basis (patients and practitioners were aware of the identity of the new lens care system). We instructed the patients on the proper use of the Pure Eyes system, including the need to rub and rinse lenses prior to disinfection.

At the end of 30 days, we evaluated the patients as we had on the initial visit. We also asked them to compare Pure Eyes to their previous lens care system on a continuous scale of 1 to 10, with values from 1 indicating preference for the previous system, 5 indicating no preference, and 10 indicating preference for Pure Eyes.

The data were analyzed to compare the Pure Eyes system to ReNu and Opti-Free, and only paired results were used for statistical analysis. In some cases, certain results were inadvertently not obtained or recorded at the final study visit, so paired observations may vary in number. For instance, in two cases for the ReNu users, one of the overall comfort grades was not available. This is reflected in the data summaries.

RESULTS

Those patients who expressed a preference at the end of the study (Fig. 1) preferred Pure Eyes 3 to 1 (46 vs. 14).Patients graded the Pure Eyes system higher for both lens insertion comfort (Wilcoxon, p=0.2915) and overall lens comfort (Wilcoxon, p<0.05) and lower for ease of use (Wilcoxon, p<0.05) than the comparative systems (Fig. 2).

Fig. 2: Subjective Gradings

Fig. 3: Frequency of Rubbing Lenses

The frequency of lens rubbing and rinsing was significantly greater for Pure Eyes use than with the comparative systems (Fig. 3).

Fig. 4: Frequency of Deposits by Amount

Lenses cleaned with the Pure Eyes system exhibited fewer deposits (determined by slit lamp observation using a CCLRU scale) than those cleaned with the comparative systems (p<0.05) (Fig. 4). Pure Eyes also produced fewer protein and combined lipoprotein deposits than either ReNu or Opti-Free (Fig. 5).

Fig. 5: %of Patients with Specific Deposits

Pure Eyes had statistically significant lower average grades for epithelial disruption with (Wilcoxon, p<0.05) and without (Wilcoxon, p<0.05) fluorescein, redness (Wilcoxon, p<0.05), and microcysts (Wilcoxon, p<0.05) than the comparative group (Table 1).

CONCLUSION

Study results indicate that a majority of patients preferred Pure Eyes over their previous multipurpose lens care system. This may be due to to better overall lens comfort resulting from fewer lens deposits and better slit lamp findings with Pure Eyes.

Pure Eyes disinfectant (hydrogen peroxide) does not contain preservatives which could cause sensitivities. The reduced deposit formation may be related to: lower toxicity of the nonpreserved, neutralized hydrogen peroxide, resulting in fewer corneal sensitivities; and increased patient compliance with rubbing and rinsing the lenses prior to disinfection compared to the previous regimens. We cannot rule out the possibility that change to any system and re-instruction on lens care would have improved the results.

It's important to note that a majority of patients preferred Pure Eyes over their previous system despite the fact that they were rubbing and rinsing their lenses more frequently. This compelling fact reinforces the importance of these steps in promoting contact lens success and patient satisfaction. CLS

This study was sponsored by CIBA Vision Nordic. Processing of statistical data was done by Bill Long, clinical systems specialist at CIBA Vision Ophthalmics Communications.

Dr. Seland, a graduate of the School of Optometry in Norway, is chairman of the Norwegian Contact Lens Association. Educated in Denmark, Dr. Kryger is employed by Seland Optikk Clinic.