A Patient-Acceptance Study of a Switch in Lens Care Systems


A Patient-Acceptance Study of a Switch in Lens Care Systems

By Joseph P. Shovlin, OD
March 2000

The use of soft contact lens care systems with hydrogen peroxide as either the disinfecting agent or the solution preservative is due largely to the belief that such systems offer greater disinfection efficacy and a lower likelihood of sensitivity reactions. On the other hand, chemical-based care systems are often thought to provide greater convenience, which may in turn lead to greater patient compliance.

As part of a larger investigation undertaken to establish patient acceptance of Alcon Laboratories' New Opti-Free Express Multi-Purpose Disinfecting Solution with Enhanced Disinfection and Aldox, a subset of subjects using peroxide-based care systems was identified. A prior investigation established that this new product provides a level of lens disinfection on a par with that of peroxide-based systems. This study contrasts the frequency of slit lamp findings and subjective symptoms with New Opti-Free Express in patients with prior experience using hydrogen peroxide-based systems.


A subset of 49 patients currently using hydrogen peroxide-based care systems were identified as part of the group of 212 subjects enrolled in the patient-acceptance study of New Opti-Free Express. All subjects were seen at baseline, and for follow-up evaluation after three months of wear. After providing informed consent and undergoing slit lamp examination at the preliminary visit, each subject completed a questionnaire regarding their symptoms of burning or stinging, lens dryness and lens awareness with their pre-study lenses. The scale used for these ratings was 0 = no symptoms, 1 = trace, 2 = mild, 3 = moderate and 4 = severe. Additionally, each participant was asked to report on pre-study contact lens comfort, satisfaction with wearing time and habitual lens care product convenience using a 1 to 10 scale, where 1 = extremely dissatisfied and 10 = extremely satisfied.

Patients were dispensed a new pair of lenses identical to their pre-study lenses, along with New Opti-Free Express Solution. Each subject was instructed to use the solution in accordance with the manufacturer's directions for use. No separate surfactant cleaner or enzyme removal product was used in the study. Of the 49 subjects represented in this investigation, 25 previously used AOSept (CIBA Vision), 18 used the QuickCare System (CIBA Vision) and six used The Ultracare System (Allergan).

At the three-month visit, the investigators performed a slit lamp examination for edema, neovascularization, staining, injection, and tarsal abnormalities. Findings were recorded using a 0 to 4 scale (0 = none, 1 = trace, 2 = mild, 3 = moderate, 4 = severe). Each subject completed another questionnaire, reporting on subjective symptoms of burning or stinging, lens dryness and lens awareness with their study lenses. Finally, each subject again reported on overall contact lens comfort, satisfaction with contact lens wearing time and product convenience using the same 1 to 10 scale described above, with these results to reflect their experience with New Opti-Free Express after three months' use.


TABLE 1:  Frequency of Slit Lamp Findings Grade 2 or Above

Baseline Visit 0 3 2 1 0
Three-month Visit 0 0 0 3 0


The frequency of reported symptoms by severity at baseline and three months are reported against the total number of eyes enrolled (98), as shown in Figures 1 and 2. The overall frequency and severity of patient-reported symptoms didn't increase significantly from pre-study levels, with 48 out of the 49 subjects reporting either no or trace amounts of burning or stinging at the three-month visit. Table 1 (above) summarizes the frequency of slit lamp findings grade 2 or above. There were no noteworthy changes reported by the investigators between baseline and the three-month visit.

FIG. 1: Baseline Visit Symptoms by Frequency (n = 98)

FIG. 2: Three-Month Visit Symptoms by Frequency (n = 98)

The average pre-study response on the subject questionnaire regarding lens comfort and satisfaction with lens wear time was 8.55 and 8.45 respectively, based on the 1 to 10 scale described. In comparison, the three-month visit responses were 8.59 for comfort and 8.43 for satisfaction with lens wearing time.


Historically, soft lens care systems that utilize hydrogen peroxide as the disinfection agent, (AOSept and UltraCare), or as the preservative in the saline rinse (QuickCare), have been chosen for their higher level of disinfection efficacy and/or for their perceived ability to limit sensitivity reactions. At the same time, there have been attempts to develop chemical-based care systems with enhanced disinfection ability that can match the low frequency of sensitivity reactions reported with peroxide-based systems.

This three-month investigation was intended to confirm patient acceptance of New Opti-Free Express MPDS among a group of established soft lens wearers already using peroxide systems. We did not screen subjects, as is often specified in other study protocols, because we felt that our results would better reflect the real world experience of the eye care professional with real patients.

Slit lamp findings remained, on average, at baseline values throughout the study, with well over 99 percent of all findings being graded 0 (none) or 1 (trace). Of potentially even greater significance, subjectively reported symptoms of burning or stinging, lens dryness and lens awareness with New Opti-Free Express didn't differ significantly from those experienced with hydrogen peroxide-based systems, despite its enhanced level of disinfection ability. The overall patient acceptance of this new product is also evidenced by the high subjective ratings for overall lens comfort (8.59 on a scale of 1 to 10), as well as for satisfaction with lens wear time (8.43) at the three-month visit.

An advantage of chemical-based care systems is their convenience over peroxide systems, which involve no less than two (QuickCare) or three (AOSept and UltraCare) different products. Patients clearly state that the convenience and reduced expense of having to purchase fewer bottles would likely affect their compliance level. These facts explain why, when asked at the study termination to judge on a 1 to 10 scale (where 10 = definitely yes and 1 = definitely no) their likelihood of purchasing New Opti-Free Express, an overwhelming 86 percent of these prior hydrogen peroxide care system users gave a response of eight or greater, suggesting a strong overall desire to continue with this new care system.

Product use convenience is important to consider in deciding upon the most efficacious soft lens care system. At the same time, you must consider disinfection capability and the likelihood of sensitivity reaction. This investigation provides evidence for the consideration of Opti-Free Express, even for patients who we would otherwise recommend hydrogen peroxide systems. Even among a subset of previously adapted hydrogen peroxide users, there was no evidence of solution sensitivity. Switching patients from hydrogen peroxide-based systems should now be easier with the introduction of this new product. 

This study was sponsored by Alcon Laboratories.

Investigators: Joseph Barr, O.D., M.S., Bobby Christensen, O.D., Michael DePaolis, O.D., Burt Dubow, O.D., Arthur Epstein, O.D., Julie Eilers-Jackson, O.D., Kenneth Lebow, O.D., Brian Pall, O.D., John Schachet, O.D., Joseph Shovlin, O.D. and Walter West, O.D.

To receive references via fax, call (800) 239-4684 and request document #58. (Have a fax number ready.)

Dr. Shovlin is director of the Contact Lens Service at the Northeastern Eye Institute, Scranton, Penn.