DAILY DISPOSABLE LENSES
Daily Disposable Lenses: A Look Back and Ahead
While some focus on the cost, others embrace the convenience and high compliance rates of the modality.
By Renee Reeder, OD
Dr. Reeder is an associate professor and the chief of the Cornea Center for Clinical Excellence at the Illinois College of Optometry. She has lectured and/or conducted research for Abba Optical, Alcon, Bausch + Lomb, Blanchard, Ciba Vision, CooperVision, Metro Optics, and Vistakon. She can be reached at email@example.com.
Daily disposables entered the marketplace in 1994 to the surprise of many. The viability of such a product began with a multi-center study using Acuvue lenses (Vistakon) on a daily disposable basis. I recall thinking, “Will patients really want this?” The results of this study showed that patients loved the comfort and convenience of replacing the lenses daily. I remember how enthusiastic many of them were about the concept.
Still, we wondered whether these same patients would continue wearing the lenses when they had to buy them. Remarkably, many of them said they would purchase them and many did after the study's conclusion. However, we still wondered whether we could get patients to try daily disposables initially if they had to pay for them. Today, cost continues to be an issue, although the issue seems to be more ours than our patients'.
The initial use of daily disposables and their continued strongest utilization is for part-time wear. It was—and still is—easier to recommend this modality for those wearing lenses occasionally. Cost is less of a factor. Convenience and compliance are key. Lens care is problematic for those using lenses part-time, and many parttime wearers stretch out one or two boxes of two-week lenses for one or two years. They see two-week lenses as 14-use lenses. Of course, that requires a patient to keep track of each use. Today, part-time wear still comprises a significant portion (approximately 60 percent according to Efron and Morgan, 2009) of daily disposable prescriptions.
There were other barriers to the modality initially, including parameter availability. 1-Day Acuvue (Vistakon) was the only product available. Thus, there was only one material with only single vision spherical correction for almost three years. In 1997, Ciba Vision entered the daily disposable race with Focus Dailies. Ciba's product brought competition to the market and encouraged the development and progression of this modality. In the last several years, there has been rapid growth in availability and options within the modality (Table 1).
Despite increased availability, daily disposable lenses have exhibited very slow growth in the United States, in which they account for only 10 to 15 percent of contact lens sales annually. Elsewhere in the world, single-use lenses exceed 50 percent of the market. With so much availability and so much on the horizon, why the disparity?
Daily disposables are now available throughout the world and in a wide range of parameters (Table 2).
There are very few prescriptions that cannot be accommodated with daily disposable lenses for single vision prescriptions, and there are more than a dozen options available in spherical correction. These offerings include both low- and high-water options, biomimetic materials, colors, and silicone hydrogels (SiHy). Spherical power availability ranges from +8.00D to −12.00D.
Toric expansion has also been significant. There are now three players in astigmatic correction, and they offer cylinder powers from −0.75D to −1.75D. Additionally, toric options are available in up to six axes. There are even axis markings on the lenses now so we can make axis changes if necessary.
Presently, there is still only one multifocal option, the Focus Dailies Progressives (Ciba), which has one nominal add power.
When you consider that 90 percent of lenses prescribed in North America are for myopia with aver-age powers of −3.00D to −3.25D, there is now a daily disposable lens for almost everyone.
What about patients who are active outdoors? Many daily disposable lenses are available with UV protection. While UV contact lenses will never replace the need for good sunglasses, sunscreen, and a hat to protect the delicate skin of the eyelids and surrounding the eye, they are a start to protecting the lens and the retina from harmful UV rays.
SiHy daily disposables became available in the United Kingdom in 2008. Some are concerned about patients trying to sleep in their daily disposable lenses, and there certainly are blogs that indicate that some overnight wear is occurring. However, it is encouraging to note that 85 percent of current daily disposable wearers report that they never sleep or only nap in their lenses. Given that, do we even need SiHy daily disposables? As Harvitt and Bonanno (1999) have found that the open eye oxygen transmission (Dk/t) should be, at minimum, 35, then we have to realize that our current hydrogel options fail to meet this need, even with a −3.00D prescription. So where does that leave the +6.00D or −10.00D patients?
Over the course of 2005 to 2007, there were lens solution recalls and serious microbial keratitis outbreaks. Acanthamoeba studies found that showering while wearing lenses was a risk factor. Does anyone know a continuous wear SiHy patient who takes his lenses out to shower? However, daily disposables used properly can eliminate this risk.
Daily disposable lenses also eliminate solutions. This is a definite benefit when you consider that none of the currently available solutions were effective against Acanthamoeba after a standard six-hour disinfection cycle (Shoff et al, 2008). In fact, the clinical isolates required hours of direct exposure to hydrogen peroxide to kill even a portion of the cysts. Exposing a lens to peroxide for such a duration would cause significant lens swelling and distortion of the optics.
Discarding lenses, especially potentially contaminated ones, after one use does appear to provide the greatest hope for reducing—but not eliminating—risk. But when we look at the sales of daily disposables, especially within the United States, we do not see that large increase in utilization that you might expect. In Japan, sales have jumped to 50 percent (Figure 1). The Scandinavian marketplace has also been extremely receptive, with daily disposables exceeding 50 percent since the outbreaks.
Figure 1. Graphical representation of the growth of the daily disposable modality since the keratitis outbreaks began in 2005.
Advantages: Convenience, Compliance
Ocular surface diseases including dry eye, meibomian gland disease, and allergy are known contributors to contact lens dropout. With disposable lenses, lens coating is minimized. Less coating means less exposure to allergens and potentially a more hydrated lens, both of which should enhance patient comfort and optimize patient success in lenses.
Kids and teenagers frequently struggle with keeping their rooms clean, brushing their teeth, and showering. Do we really expect them to take their lenses out every night, clean and store them properly, and rinse and dry their case each morning? Daily disposables eliminate a portion of that concern and can ease the minds of nervous parents. In addition, there is the advantage of having plenty of spares when learning to handle lenses. It is not significant to tear a few pairs of daily disposables versus a few months' worth of monthly replacement lenses.
Lifestyle is an important factor in lens selection. Having worked in a student healthcare center at a university, I learned quickly that certain folks did not always know where they were going to end up at night. It's easy to put an extra pair of daily disposable lenses in your pocket to take with you when you go out. Do we really expect patients to carry a case and solution with them when they go out for a night on the town? How about on an overnight business trip when you don't want to check your luggage?
Lens replacement is another concern. We continue to combat infections, illegal lens sales, and over use and abuse of contact lenses by patients. Study after study has shown that the highest level of compliance is with daily disposables (Dumbleton, 2010; Sindt, 2000). While the rate of compliance may vary from the mid-70 percent range to the high-90 percent range, it still far exceeds the 30 to 60 percent compliance rate of two-week and monthly replacement.
The latest data reported by Dumbleton et al (2010) indicates that patients often forget which day they are supposed to replace their lenses. In fact, forgetting which day is the most common reason that patients report for failing to replace lenses on time. Replacing lenses daily eliminates this concern. Further, 82 percent of U.S. patients and 74 percent of Canadian patients reported that they always replace one-day lenses as prescribed. This far exceeds two-week and monthly replacement rates. The percentage of Canadian patients who say they always replace their lenses per the recommended schedule is at a much lower rate of 36 percent. When you take into consideration compliance with replacement, compliance with solution, and the convenience of dailies, you really have to wonder why they remain so underutilized in certain parts of the world.
The Cost Issue—or Cost Excuse
Time and time again when practitioners are surveyed, they report that cost is the barrier to daily disposable lenses. Yes, they are more expensive. How much more? A properly used cleaning system with regular replacement of lens cases should cost patients about $100 per year. Monthly replacement silicone hydrogel lenses, based on Internet pricing, cost between $150 to $250 per year. That means the total cost is $250 to $350 per year without rebates.
Patients can purchases daily disposable lenses online for between $320 to $520 per year. Additionally, daily disposable rebates tend to be higher than those of two-week and monthly lenses. Some one-day rebates are as high as $100 on a one-year supply. All this demonstrates that the price gap is certainly narrowing while the benefit gap is only widening.
Much work is being performed today on drug delivery systems. Daily disposable lenses may provide a vehicle for such options. Imagine a daily disposable lens with the allergy medicine in the package, or perhaps a time release version of glaucoma medication to prevent diurnal spikes in the intraocular pressure.
Material options and lens parameter availability continue to increase. With the improvements we have observed in two-week and monthly replacement multifocal designs, one can only hope that we will see such offerings in the daily disposable realm.
Cosmetic tints have continued to decline for fulltime wear, making the use of daily disposable options a fun, fashionable choice for occasional wear. As materials continue to improve, improved options for patients who have challenging tear films and comfort issues can be expected.
Manufacturers are making rapid improvements in technology. The amount of new products released in the last few years and since the keratitis outbreaks began is revolutionary. Will you join the revolution?
When I asked practitioners at a recent continuing education program what lenses they wore, the majority indicated that they wore daily disposables. For several years, lens companies that work with the educational institutions to provide educational lenses for students have reported that daily disposables are the most widely used modality within their programs. Maybe it is time for us to believe that our patients want what is most convenient despite price, too. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #173.