THE TOPIC DISCUSSED here may be controversial, but in my opinion there are only two ways to look at product innovation. First, one can believe that new and innovative products should always be used because they are better—better for the patient and better for the practice. Others say we should not fix things that are not broken, unless the evidence base demonstrates definitively that the newer technology is better for the patient.

Rarely is that evidence base illuminated upon U.S. Food and Drug Administration (FDA) approval. It can take years for the evidence base to catch up to FDA approval of a new product. One can look at the development of the evidence base regarding silicone hydrogel (SiHy) and daily disposable contact lenses for an example. 

In the 1970s and 1980s, soft contact lenses were shown to cause corneal swelling—especially in the closed eye state (Holden and Mertz, 1984; Mertz, 1980). In the 1990s, the “Chang Patent” described a new type of lens material class—silicone hydrogel (Chang and Chang, 1998). SiHy lenses have since taken over market share by category. In 2022, these materials made up 88% of the soft contact lens market in North America (Grand View Research, 2022).

Over the last 25 years, most of the new products on the market have been in the SiHy product category, and the companies that have invested a lot of time and treasure to bring these new products to market have, understandably, encouraged prescribers to switch to these products.

But does the evidence base support mass conversions? Well, the prevalence of microbial keratitis (MK) hasn’t budged at all—even with all the new materials and modalities (Szczotka-Flynn et al, 2021). However, success in lens wear is not all about MK. Have the new materials and modalities moved the needle relative to the older materials and wearing schedules? The answer is a qualified yes (Chalmers et al, 2015).

There seems to be little question that newer materials and modalities, especially daily disposable (DD) lenses, reduce the frequency of corneal infiltrative events and other contact lens-related adverse events (Chalmers et al, 2015).

So, what does this say about the business of contact lens practice? We should support the industry that provides us with new materials and modalities by offering their products and treatments to our patients. And as the evidence base confirms the risks and benefits of these new materials and modalities, we must adjust the way we use them accordingly.

For example, the TEMPO Registry (Chalmers et al, 2015) showed that older patients tend to experience more adverse events with SiHy DD lenses than with hydrogel DDs. So, what should be done with that information? Maybe move older patients who have adverse events from SiHy DDs to hydrogel DDs sooner rather than later.

Finally, should you fix things that are not broken, or should every patient get the latest and greatest? One downside to keeping people in older materials and modalities if they are doing well (which has been my usual choice) is that it leaves your practice vulnerable to discontinuations of lens brands. When you have a large number of patients in a lens that has been discontinued, it is tough to switch them all.

REFERENCES

1. Holden BA, Mertz GW. Critical oxygen levels to avoid corneal edema for daily and extended wear contact lenses. Invest Ophthalmol Vis Sci. 1984 Oct;25:1161-1167.

Mertz GW. Overnight swelling of the living human cornea. J Am Optom Assoc. 1980 Mar;51:211-214.

3. Chang SH, Chang MZ. Soft Gas Permeable Contact Lens Having Improved Clnical Performance. United States Patent. 1998 Jan; 5,712,327. Available at patentimages.storage.googleapis.com/c5/0b/8f/19a0d9e867aa5b/US5712327.pdf. Accessed 2024 April 24.

4. Grand View Research. Contact Lenses Market Size, Share & Trends Analysis Report By Material (Hybrid Lens, Silicone Hydrogel), By Design (Spherical Lens, Toric Lens), By Application, By Distribution Channel, By Usage, And Segment Forecasts, 2023 – 2030. 2022. Available at grandviewresearch.com/industry-analysis/contact-lenses-market. Accessed 2024 April 24.

5. Szczotka-Flynn LB, Shovlin JP, Schnider CM, et al. American Academy of Optometry Microbial Keratitis Think Tank. Optom Vis Sci. 2021 Mar 1;98:182-198.

6. Chalmers RL, Hickson-Curran SB, Keay L, Gleason WJ, Albright R. Rates of adverse events with hydrogel and silicone hydrogel daily disposable lenses in a large postmarket surveillance registry: the TEMPO Registry. Invest Ophthalmol Vis Sci. 2015 Jan 8;56:654-663.