Contact Lens Spectrum
Issue:
August 2009
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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
four
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