Solution Drops Digital Cleaning Step
By Mary Jo
Stiegmeier, OD, FAAO
A multi-purpose disinfecting solution receives FDA clearance to drop the rubbing step.
Although rubbing contact lenses to clean them has long been part of every soft lens care system, patients consider this step inconvenient and sometimes omit it.
Recently the Food and Drug Administration cleared Opti-Free Express Multi-Purpose Disinfecting Solution as the first multi-purpose solution that does not require a rubbing step. This no-rub clearance covers soft lenses worn for up to 30 days. Data to support all soft lens wearing schedules has been submitted for review by the FDA.
Safely eliminating the rubbing step requires a significantly enhanced disinfecting solution, with greater cleaning, protein removal and antimicrobial capability. To be marketed as a no-rub product, the test disinfecting product must achieve the same level of disinfection efficacy without a rub as today's products achieve with a rub. The FDA guidelines and Draft ISO Standards require a 5-log (99.999 percent) reduction of each of five test organisms when tested using the product's full directions for use. The product must also clinically demonstrate the ability to keep lenses clean.
We report here on a clinical investigation conducted to establish the cleaning effectiveness, safety and patient acceptance of Opti-Free Express MPDS when used without manual rubbing for contact lenses worn up to 30 days.
Some 133 adapted soft contact lens wearers were enrolled in the study. Subject selection was limited to individuals currently wearing either FDA Group I (low water non-ionic) or Group IV (high water ionic) lenses. There were no other restrictions regarding patient age, gender, occupation or reason for using contact lenses. Subjects randomly received either Opti-Free Express MPDS (without rubbing) or Bausch & Lomb ReNu MultiPlus Multi-Purpose Solution (with contact lens rubbing in accordance with the manufacturer directions for use).
Both the patient and eye care professional were masked as to the lens care products being used. All subjects were seen at baseline and for follow-up evaluation after 14 and 30 days of wear. At the baseline visit, after providing informed consent and undergoing slit lamp examination, subjects rated the overall comfort of their pre-study lens care regimen on a three-point scale as either very comfortable, comfortable or uncomfortable.
Group I lens wearers were fitted with several 38 percent water polymacon lenses (Biomedics 38, Edge III Proactive, Hydron Zero 6, Optima 38, Optima FW, Soflens Series U4). Group IV lens wearers were fitted with Surevue lenses (etafilcon A, 58 percent water). Subjects wore the new lenses on a daily-wear basis only, with a minimum wear time of eight hours per day and no scheduled lens replacements for the duration of the study.
At each visit, investigators recorded average wear time and visual acuity and performed a slit lamp examination and visual quantification of lens deposits using a modified Rudko scale.
Practitioners recorded slit lamp findings for edema, injection, staining, infiltrates, neovascularization and tarsal abnormalities using a 0-4 scale (0=none, 1=trace, 2=mild, 3=moderate and 4=severe). Subjects reported on subjective comfort of their assigned study regimen. After the final visit, investigators collected all contact lenses worn for the duration of the study for laboratory evaluation of residual lysozyme levels at Alcon Laboratories.
Some 130 (97.7 percent) subjects completed the one-month evaluation. One subject did not return for follow-up, and two dropped out due to solution-related reactions, one with Opti-Free Express and one with ReNu MultiPlus.
Lens deposits as visually graded by Rudko examination were reported as none or minimal (Type I or II) at 30 days for better than 97 percent of all subjects regardless of treatment group.
To quantitatively evaluate the cleaning effectiveness of each regimen, protein remaining on the lenses at the end of the study was measured using high performance liquid chromatography (HPLC) by laboratory technicians who were masked as to the treatment group used for each lens. Technicians evaluated only lenses which had been worn for the entire study period. Averaged laboratory measured residual lysozyme levels were evaluated separately for the FDA Group I and Group IV lenses. Evaluating each group separately was desirable because Group IV lens materials (high water ionic), which make up over 70 percent of the lenses sold in the United States, can accumulate up to 170 times more protein than a lens from a Group I material.
The average residual lysozyme on the Group IV lenses for Opti-Free Express without a rub was significantly less as compared with the ReNu MultiPlus with a rub
(Table 1). Results for Group I lenses which absorb much less protein were substantially equivalent
Investigators reported no clinically significant slit lamp findings (grade 3 or above) for either of the treatment groups. Over 90 percent of all subjects judged their overall regimen comfort as very comfortable or comfortable throughout the study
(Table 3). Visual acuity and wearing time were maintained consistent with baseline throughout the study for both lens care regimens.
Some 20 lenses required replacement during the course of this investigation: nine due to lost or damaged lenses, five due to subject or practitioner error, four due to changes in lens power or base curve and two because of solution-related irritation. Both lens replacements for solution irritation occurred with ReNu MultiPlus.
Patients dislike and often skip rubbing their contact lenses. Evidence from this clinical investigation suggests that Opti-Free Express Multi-Purpose Disinfecting Solution without the rubbing step provides the same level of comfort, slit lamp findings and patient acceptance benefits as ReNu MultiPlus used with daily manual rubbing.
Further, Opti-Free Express without a rub was shown to significantly reduce the buildup of protein deposits on Group IV lenses when compared to ReNu MultiPlus with a rub. This may be attributed to the cleaning system incorporated in the Opti-Free Express formulation which both removes proteins and lipids and inhibits their formation on the contact lens surface during the soaking phase.
The hurdle of eliminating the need for daily contact lens rubbing may have been overcome. The performance of No Rub Opti-Free Express sets a new standard for patient convenience without sacrificing performance.
The following practitioners served as investigators in the study: Richard Benninger, MD; Peter Bergenske, OD; Ronald Cedrone, OD; James Key II, MD; Joseph Lavaux, OD; Ken Lebow, OD; James McCulley, MD; Gary Meier, OD; Glenda Secor, OD.
This study was sponsored by Alcon Laboratories.
References are available upon request. To receive references via fax, call (800) 239-4684 and request document #64. (Be sure to have a fax number ready.)
Dr. Stiegemeier is in private practice in Beachwood, Ohio. She lectures throughout the country on the subject of contact lenses and performs clinical research.
TABLE 1: Average Residual Lens Lysozyme-Group IV Lenses--30 Days
TABLE 2: Average Residual Lens Lysozyme-Group I Lenses--30 Days
TABLE 3: Percentage of Subjects
Reporting Very Comfortable or
Comfortable Regimen by Visit
|Day 0 (Pre-Study)
Contact Lens Spectrum, Issue: September 2000