Caring for GP Lenses, the Material Matters
JEFF SCHAFER, OD, MS
Choosing a care system often requires considering
many factors, including but not limited to lens type, wearing schedule, cost, convenience,
managing deposits, preservative sensitivities and, of course, the
contact lens material. Knowing the characteristics of the material you're fitting
will help when troubleshooting problems with wettability, comfort, fit or even vision.
In today's lens practices, most GP lenses are manufactured from
fluorosiliconeacrylate (FSA) materials. FSA materials generally offer excellent
oxygen transmissibility while maintaining surface wettability. They also have decreased
susceptibility to protein deposition. However, their surfaces can be more lipophilic,
leading to hazy areas of non-wetting when contacted with various cosmetics, soaps,
lotions and creams.
When fitting GPs manufactured with high-Dk FSA materials, recommending
compatible care systems is critical to maintaining a clean, wettable surface.
Train patients on proper lens handling techniques and caution
them to rinse any oils, lotions or soap from their hands before touching their lenses.
Patients should avoid abrasive lens cleaning products such as Boston Original cleaner
and Boston Advance cleaner (Bausch & Lomb) in high-Dk FSA materials including
Menicon Z (Menicon Co., Ltd.), HDS-100 (Paragon Vision Sciences) and Boston XO (B&L)
to avoid damaging the lens surface. Better alternatives for these delicate materials
are Optimum by Lobob (Lobob Laboratories), Unique pH (Alcon Laboratories) and Boston
Optimum Cleaning/Disinfecting/Storage (CDS) solution allows the
lenses to soak overnight in a surfactant that dissolves lens deposits and retains
a wettable surface. Patients may perform a digital rub cleaning step with the CDS
solution or with a separate Extra-Strength Cleaner (ESC) for tough deposits. Optimum
is preserved with benzyl alcohol, and after soaking in CDS solution, the patient
must rinse the lens with saline before applying it to the eye.
Unique pH is preserved with Polyquad and contains the surfactant
Tetronic 1304. It contains HP guar, also found in Systane, which allows for a low
viscosity for overnight wetting, but at the pH of the tears increases in viscosity
to provide cushioning and greater wetting after lens application.
Boston Simplus is also a one-bottle multipurpose product that's
gentle on lens surfaces. It's preserved with chlorhexadine, PHMB and EDTA, which
sometimes leads to preservative sensitivity. Simplus contains the cleaning agents
PEO sorbitan monolaureate and betaine, the surfactants poloxamine and hydroxyalkylphosphate
and the lubricating agents glucam-20 and HPMC.
The disadvantage of systems that don't contain an abrasive cleaner
is in controlling heavy protein deposits. In these patients, I incorporate a liquid
enzyme such as Boston One Step Liquid Enzyme Cleaner (B&L) or SupraClens Daily
Protein Remover (Alcon). If enzyming isn't effective, then I occasionally clean
the lenses with Progent (Menicon), which is an in-office, intensive protein remover
for GP lenses. If heavy lipid deposits are a problem, then an in-office cleaning
with Fluoro-Solve (Paragon Optical) or Boston Laboratory Cleaner (B&L) usually
does the trick.
For more information on GP materials and solutions, check out
the online version of Contact Lenses & Solutions Summary at clspectrum.com
or the GP Lens Institute at www.gpli.info.
Dr. Schafer is the chief
of Contact Lens and Disease Services at The Ohio State University College of
Contact Lens Spectrum, Issue: September 2006