Contact Lens Spectrum
Issue: August 2009
contact lens care and compliance
A New Technology in Lens Care
BY SUSAN J. GROMACKI, OD, MS, FAAO
The challenges associated with developing an optimal lens care solution are not always appreciated by practitioners and patients. It takes, on average, five-to-seven years from idea to market-place. One reason it's so difficult: the active ingredients or preservatives must be strong enough to kill pathogens and to maintain solution sterility, but gentle enough to prevent damage to ocular tissue. The solution must also be compatible with eye and tear chemistry in areas such as pH and osmolarity. A perfectly efficacious system may theoretically be quite cumbersome and expensive, but patients, of course, desire convenience and low price.
In addition, interactions among the solution, lens material, and contact lens case must also be taken into account. For example, silicone hydrogel lenses have different compositions and solution uptake rates than traditional hydrogels do. This can, in turn, lead to issues such as solution-induced lens parameter alterations or corneal staining.
We now understand these challenges more than ever, having experienced two outbreaks of microbial keratitis and two recalled solutions — both of which passed the United States Food and Drug Administration's recommended testing procedures.
Looking Outside of Eye Care
Enter some outside-of-the-box thinking, courtesy of the water purification industry. As briefly described in my June column, ozone is being investigated as a potential contact lens disinfectant. Alab LLC is developing a device called QuickPure (Figure 1) that, although not yet commercially available, is in its sixth generation prototype stage.
Figure 1. The QuickPure Contact Lens Sanitizer.
The unit creates ozone from oxygen in the air via electricity from a battery. According to the company's Web site, ozone (O3), or "activated oxygen," is the "most powerful disinfectant known." One part-per-million of ozone can kill pathogens that would resist 30,000 parts per million of 3% hydrogen peroxide. Alab LLC states that, at concentrations so low, contact lenses can be placed directly onto the eyes after disinfection and that any additional ozone reverts back into oxygen.
The Perfect Lens Care System?
Ozone kills bacteria, viruses, yeasts, algae, fungi, and protozoa, including Acanthamoeba trophozoites and cysts. Because it eradicates microbes by destroying their cell membranes, microorganisms are unable to evolve resistance. In addition to disinfection, the QuickPure process also cleans lenses by destroying biofilms and by agitation.
The technology requires no rubbing or rinsing of the contact lenses. The lenses are placed in the lens holder after removal from the eyes. The cup is then filled with a proprietary isotonic buffered saline. The lens holder is placed in the cup, and the cup is then placed into the base unit. This turns on the disinfection process, which automatically turns off after three minutes. The company states that the ozone inactivates 99.99 percent or more of the FDA's challenge organisms in this time period. The unit is battery-powered for easy transport, and the lens cup may be removed from the base and carried separately.
A Work in Progress
Alab LLC has obtained
For references, please visit www.clspectrum.com/references.asp and click on document #165.
Dr. Gromacki is a Diplomate in the Cornea and Contact Lens section of the