Annual Soft Contact Lens Solution Usage and Costs

Julie A. Schornack, OD, MEd, Ronald Watanabe, OD, Sally M. Dillehay, OD, MS, Steven Grant, OD, Douglas W. Stephey, OD and Glenda Secor, OD
AUGUST 1998

Cost is a key factor in how compliant patients are with their lens care.  This multisystem comparison may help you decide how to best present the system you prescribe.

Determining the estimated annual cost of a prescribed contact lens care system is much more difficult than estimating the annual cost for a patient's contact lens materials and services. There are several variables that can significantly alter the annual volume of a care system used by the patient, including: replacement schedule for contact lenses, extended versus daily wear schedules, full-time versus part-time wear, compliance with care system directions, care system complexity and pricing.

Previous Findings

Earlier studies examining estimated total annual costs of care systems for the average patient have varied greatly. Some of the variation can be attributed to the differences in the methods used. Silbert (1993) conducted a study that investigated the annual usage of four systems, assuming that the patient adhered to manufacturer's recommendations. According to the study, the annual estimated cost of AOSEPT was $231.65, ReNu was $318.45, Opti-Free was $388.84, and UltraCare was $499.83.

In an attempt to more accurately address usage, Reindel (1992), looked at consumer-based research that determined how much solution was purchased by an individual over a given time period. This study concluded that consumers spent only $82.45 annually on a hydrogen peroxide system and an average of $38.14 annually on multi purpose systems. The technique used to gather this information may underestimate the true costs of the system, but the magnitude of underestimation does not account for these stark differences as compared to Silbert's projected costs. The contrast in annual expenditures is most likely attributed to compliance-based issues.

Data Collection and Calculation

Several new lens care systems have recently become available and the costs to our patients have changed as well. In this study, we determined and compared the average volume of seven different soft contact lens care systems used by patients. We gathered pricing information from manufacturers, mass merch- andisers, grocery stores and drug stores, and used national Nielsen data to determine and compare associated annualized patient costs of these seven lens care systems, given the average volume used for each system.

We randomly assigned 406 patients who had worn hydrogel contact lenses for a minimum of three months to one of the following seven different soft contact lens care systems: Complete (Allergan), Opti-Free (Alcon), Pure Eyes, Quick CARE and SOLO-care (CIBA Vision), ReNu (Bausch & Lomb), and UltraCare (Allergan). We instructed study participants to wear their lenses for daily wear during the study, even if they were typically extended wear patients. We instructed patients to use the systems according to the manufacturer's specifications. Patients currently using enzymes were told to continue usage in accordance with the indications of the assigned system. If a patient was randomly assigned to his habitual system, he was still dispensed that solution, but told to use it according to manufacturer's directions.

We instructed all patients to use the care system for a two-week period and then return all the bottles and remaining solutions to the study center. We again asked patients how many days they used the system. They were not informed of the nature of the study nor of the sponsor, to safeguard against altered usage patterns of the care systems or bias on the part of the patient.

We weighed and marked each bottle with an identification number prior to dispensing the products to patients. At the end of the study, we again weighed each bottle with the remaining solution in it and then emptied it into a volumetric flask to determine how much solution was left unused. We weighed each empty bottle and calculated the total volume of solution used by each patient.

To determine the calculated volume used per day, we divided the number of days each patient reported using the system into the calculated total volume used. We made random calls to mass merchandisers, grocery stores and drug stores in four regions throughout the country to determine the retail prices of the specific care products (Table 1). National costs were based on the average retail prices reported by A.C. Nielsen Corporation in 1996, and we used the suggested retail price for the SOLO-care brand, since it was not yet available at the time of the study.

To determine the annual costs of each lens care system to the patient, we multiplied the mean daily usage by 365 days to determine an annual volume usage, which we divided by the volume of each product's bottle. We then muliplied this result by the cost for that size bottle from a specific retail location to determine the annual cost of the system.

Results and Theories

Table 2 shows the daily usage values for each product of the seven care systems. The observable variation in daily usage among all the systems is evidenced by the disparity between minimum and maximum daily usage totals, and may be a result of patient compliance with the system instructions.

Although the rub and rinse portions of any contact lens care system are crucial to maximizing the care system's efficacy, they are also the steps that patients choose to shortcut. Some of the minimum daily usage numbers are actually less than the average contents of a lens case (approximately 2.75 - 3.00ml per well). This occurred even though patients were thoroughly instructed on how to use each system and were directed to use the system per its instructions.

Among the multi purpose solutions used in this study (ReNu, Complete, and SOLO-care), we found an interesting difference in daily usage despite the similarity of the instructions. Nearly 26 percent more ReNu than Complete was used on a daily basis and 17 percent more ReNu than SOLO-care was used. However, the percentage of patients on each system using enzyme tablets didn't explain this difference in daily usage. Slightly more patients who were randomly assigned to the Complete system used enzymes than did those randomly assigned to ReNu or SOLO-care.

A second possibility for the increased use of ReNu over SOLO-care and Complete on a daily basis is the difference in the volume of the lens cases used for overnight disinfection purposes. However, an inspection revealed that the volume of each well in the ReNu, SOLO-care and Complete lens cases is 2.75ml, 2.75ml and 3.00ml, respectively. Therefore, the volume of the lens case does not seem to account for the difference in daily usage either.

The third theory to account for the higher daily usage of ReNu was the aperture size on the bottle. This could lead to greater volumes of solution being dispensed for similar time periods, especially during rinsing. To test this theory, we sent 12-ounce bottles of ReNu, SOLO-care and Complete to the Department of Packaging Science at a major university. Here, each bottle was cut to expose the limiting orifice. A sewing needle was then placed in the orifice and marked with a felt tip pen at the point of the limiting orifice opening. The thickness of the needle was measured at that point. The aperture sizes were found to be: 0.030 inches for ReNu, 0.028 inches for SOLO-care and 0.023 inches for Complete. Additional testing was also done on the diameter, the thickness of the sidewalls, the surface area, and the weight of each bottle. Small differences were found to exist in these areas as well.

Lastly, to simulate actual patient usage, a force of 5lbs. of pressure was applied to each bottle, and the amount of solution that was expelled by this force was measured. On average, an equivalent of force dispensed 65 percent more ReNu than SOLO-care, 15 percent more SOLO-care than Complete and almost 90 percent more ReNu than Complete. Overall, the lab felt that the small differences in bottle diameter combined with the differences in orifice size were the cause of these different usage rates.

Silbert's data suggested that the daily use of a multi purpose solution used compliantly according to manufacturer instructions should be approximately 45ml. In this study, the average daily usage of all three multi purpose systems was approximately one-third of that amount; another possible indication that we need to strongly discuss and reinforce compliance with patients on these systems.

Table 3 shows the annual cost of each lens care system based on the average daily volumes used and the A.C. Nielsen average retail price date. We found UltraCare to be the most expensive and SOLO-care to be the least expensive of the systems.

The Bottom Line

This study provides practitioners with information about actual usage patterns and annual costs associated with seven different soft contact lens care systems. This information can be useful when advising patients on costs associated with specific care systems. The ultimate annual cost of a contact lens care system may have some impact on a patient's adherence to recommended contact lens care regimens. CLS

This study was sponsored by CIBA Vision Corporation.

Dr. Schornack serves on the executive committee of the association of contact lens educators; Dr. Secor practices in Huntington Beach, Calif. Dr. Watanabe practices part-time in New Hampshire and Dr. Dillehay is manager, academic development at CIBA Vision.Dr. Stephey is in private practice in covina, calif and Dr. Grant owns and operates his private practice in Costa Mesa, Calif.