Sponsored by CIBA VISION®
A 2009 study conducted by the Centre for Contact Lens Research at the School of Optometry at the University of Waterloo (CCLR) provides new definitive evidence about low rates of compliance of two-week replacement lens patients with replacement schedules recommended by manufacturers and ECPs.
Participants in the large study included 1,654 patients of 158 U.S. practices, including 265 daily disposable lens wearers, 741 wearers of two-week replacement silicone hydrogel lenses and 648 wearers of monthly replacement silicone hydrogel lenses. Lens brands worn by patients in the sample included those of all the major manufacturers and the distribution of brands worn approximates the U.S. market shares of the lenses. The demographic and lens wearing habits of patients in the study sample mirror those of all U.S. soft lens wearers.
Patient Characteristics and Wearing Habits
- 66 percent women, 34 percent men
- Mean age: 34 years; median age: 32 years
- Mean years wearing contact lenses: 12.9
- Mean days per week wearing lenses: 6.2
- Mean hours per day wearing lenses among daily wear patients (88 percent of sample): 12.8
The study revealed that for daily disposable and monthly replacement silicone hydrogel lenses nearly all ECPs recommended a lens disposal schedule consistent with the manufacturer’s recommended replacement schedule. But for 18 percent of patients wearing two-week replacement silicone hydrogel lenses, ECPs recommended a longer replacement interval (generally one month).
Table 1 shows the compliance rate for patients whose ECPs recommended a replacement interval the same or shorter than that recommended by the lens manufacturer. Eighty eight percent of daily disposable lens wearers were compliant, compared to 72 percent of monthly replacement silicone hydrogel lens wearers and 48 percent of two-week replacement silicone hydrogel lens wearers. Of all two-week replacement lens wearers in the sample (including patients whose ECPs recommended a longer interval between replacements), just 39 percent of two-week replacement lens wearers replaced lenses every two weeks or more often.
TABLE 1
Patient Compliance with Manufacturer Recommended Replacement Schedule
(% of patients when manufacturer recommended replacement schedule consistent with ECP recommendation)
Daily
Disposable
Lenses
Two-week
Replacement
Si-Hy Lenses
Monthly
Replacement
Si-Hy Lenses
Non-compliant
12%
52%
28%
Compliant
88%
48%
72%
Non-compliant patients were slightly younger on average than compliant patients. There were no significant differences in compliance by gender, years of lens wear or days/week or hours/day of lens wear. Patients wearing toric lenses were somewhat more non-compliant.
Non-compliant patients were asked to relate their primary reasons for wearing lenses longer than their ECP recommended. As shown in Table 2, the most important reasons cited were forgetting the day to replace and to save money.
TABLE 2
Primary Reasons for Non-Compliance
(% of non-complying patients)
Forget day to replace
59%
To save money
26%
Lack of time
11%
No harm
9%
ECP said OK
3%
Discussion
The CCLR study confirms findings of other recent studies of patient compliance with soft lens replacement schedules. For example, a large national survey of
