Performance of Two Single-Solution Care Systems

BY ALAN BOIS, O.D.; DANIEL BRAZEAU, O.D., F.A.A.O.; SHARON GOLDBERG, M.O.C.L.A.; KEITH W. HARRISON, M.O.C.L.A, F.C.K.S.A.; JOHN D. JANTZI, O.D., M.SC.; GERALD S. KOMARNICKY, B.SC., O.D.; TON J.P. ROWEN, M.D., PH.D.; RIENTS VISSER, OPTOMETRIST A.N.V.O.; JAN WILLEM VAN DER LINDEN, OPTOMETRIST, A.N.V.O.
JULY 1996

In parallel 2-month and 6-month crossover studies, patients preferred the cleaning and lubricating ability of ReNu over Complete.For a multipurpose lens care formula to clean, disinfect and hydrate hydrogel lenses effectively while maintaining comfort, its composition must be complex. Each constituent must have its own chemical and physical environment, yet the components must be mutually compatible and not harmful to ocular tissue.

We evaluated two single-solution contact lens care systems in two-month and six-month crossover studies. In these double-masked studies, we compared performance on the basis of ocular response, subjective evaluation of performance and user preference. We ran the studies in parallel, but treated them as independent studies.

STUDY DESIGN AND INCLUSION CRITERIA

Each study was a randomized, double-masked, crossover study with a minimum of 100 patients. At the initial visit, we assigned either Allergan Complete Multi-Purpose Solution or Bausch & Lomb ReNu Multi-Purpose Solution and dispensed a new set of study lenses. The two-month study consisted of an initial visit with observations at weeks 1, 2, 4, 5, 6 and 8, with the crossover at week 4. The six-month study consisted of an initial visit with observations at weeks 1, 6, 12, 13, 18 and 24, with the crossover at week 12. At the crossover visits, we collected the worn contact lenses and dispensed new lenses and a supply of the second lens care system.

Study participants were adapted full-time daily wearers of the dispensed soft (hydrophilic) contact lenses for at least three months. They were required to wear their lenses a minimum of four hours per day, five days per week. Visual acuity must have been correctable with contact lenses to 20/40 or better in each eye. Because part of the study was a comparison of the participants' previous care system, they must have been using either a traditional chemical or hydrogen peroxide care system prior to inclusion in the study.

LENSES AND CARE SYSTEMS

We used Bausch & Lomb Medalist (or other polymacon lenses) and Vistakon Surevue (etafilcon A 58) soft (hydrophilic) contact lenses for daily wear. Patients received new lenses at the beginning of the study and at the crossover visit.

Solution X was Bausch & Lomb ReNu Multi-Purpose Solution, which is also known as Bausch & Lomb Sensitive Eyes Multi-Purpose Solution (polyaminopropyl biguanide [Dymed] 0.00005% as anti-microbial agent with boric acid, edetate disodium, poloxamine as surfactant, sodium borate and sodium chloride). Solution Y was Allergan Complete Multi-Purpose Solution (polyhexamethylene biguanide hydrochloride [TrisChem] 0.0001% as anti-microbial agent with edetate disodium, tyloxapol as surfactant, tromethamine and sodium chloride).

VISIT PROCEDURE

At the initial visit, we:

• performed a slit lamp examination using fluorescein;
• determined patient eligibility;
• dispensed new lenses;
• obtained visual acuities with the new lenses;
• dispensed study supplies and instructions.

• obtained lens visual acuities;
• performed a slit lamp examination using fluorescein;*
• had patients rate symptoms on a visual analog scale;
• replaced lenses if necessary; and
• dispensed study product if needed.

At the crossover visit and at the end of the study, patients completed a questionnaire.

*Note: we graded corneal staining, limbal injection, bulbar injection and tarsal conjunctival abnormalities on a 5-point scale from 'none' to 'severe.' [Editor's note: For further data analysis information, see end of article.]

RESULTS OF THE TWO-MONTH STUDY

Of the 120 patients enrolled in the two-month study, 108 completed all phases (36 males and 72 females). Like the general population of contact lens wearers, the patient sample was skewed toward females and younger patients, with 77 percent of the sample between the ages of 18 and 40.

Paired comparisons of signs and symptoms (visual analog scale) during one month of treatment with each of the lens care systems showed statistically significant differences in favor of ReNu for comfort (7.95 versus 7.59, p=0.005). There were fewer reports of dryness in the group using ReNu (7.02 versus 6.65, p=0.069). There were no significant differences between the test solution in patients' rating of vision or stinging.

In the second phase of the crossover study, we asked patients to compare the lens care solution they were using with the solution they used in the first phase. As shown in Table 1, patients were significantly more likely to prefer ReNu to Complete on cleaning ability, lubricating ability and design of the nozzle/cap.

When comparing one month of lens care with Complete and one month of lens care with ReNu, patients reported greater comfort and less dryness at the end of the wearing time with ReNu.

Users of the two solutions reported different levels of comfort although there were no objective signs of disturbed conjunctival or corneal health. There were no differences between the two test solutions in terms of corneal staining, limbal injection, bulbar injection or tarsal conjunctival abnormalities. Patients favored ReNu over Complete with respect to cleaning ability, lubricating ability and design of the nozzle/cap.

RESULTS AFTER SIX MONTHS

Of the 119 patients enrolled in the six-month study, 108 completed all phases (31 males and 77 females).

There were fewer reports of corneal staining (paired t-test, p=0.036) and limbal injection (paired t-test, p=0.022) when patients were on the ReNu phase of the study. There were no differences between the solutions in the observation of tarsal conjunctival abnormalities and bulbar injection.

As shown in Table 2, patients reported better vision, greater comfort and less dryness at the end of the day with ReNu.

As in the two-month trial, we asked patients in the second phase of the six-month trial to compare the present lens care system with the system they had used in the first phase. Patients expressed a strong preference for ReNu in this masked comparison. As shown in Table 3, patients reported a preference for ReNu on scales measuring comfort at the end of the day, less scratchy feeling, overall system rating and overall preference compared to the pre-study regimen.

Patients consistently preferred ReNu on scales measuring cleaning ability, comfort upon inserting the contact lens, packaging, nozzle/cap design and overall preference (Table 4).

CONCLUSION

The longer study allowed sufficient time for objective signs of disturbed conjunctival or corneal health to develop. Symptoms may still have anticipated signs, but objective signs of abnormalities did eventually appear. Results were in favor of ReNu over Complete in slit lamp findings, patient report of symptoms and patient comparisons of the two lens care systems with each other. There was significantly less corneal staining and limbal injection when patients participated in the ReNu phase of the study. Patients reported better vision, greater comfort and less dryness at the end of the wearing time when using ReNu.

In a direct comparison of ReNu and Complete, patients were more likely to report discomfort at the end of the day and particularly a scratchy feeling on the Complete phase of the study than the ReNu phase. Patients were also more likely to prefer ReNu in terms of cleaning ability, comfort on inserting the contact lens and overall preference. Packaging and nozzle/cap design were also rated more highly for ReNu.

As this study demonstrates, differences in the formulations of the two lens care solutions have significant effects on the performance of the solution and on patient preferences of one over the other. Slit lamp findings, patient reports of comfort and visual acuity, as well as overall preference ratings favored Bausch & Lomb ReNu Multi-Purpose Solution over Allergan Complete Multi-Purpose Solution. CLS

This study was sponsored by Bausch & Lomb, Rochester, N.Y.

Data analysis information is available upon written request to the editors at Contact Lens Spectrum. To receive this information via fax, call 1-800-239-4684 and request Document #15. (Be sure to have a fax number ready.)