contact
lens materials
Managing Lipid Deposition on Silicone Hydrogel
Lenses
BY
N. REX GHORMLEY, OD, FAAO, & LYNDON JONES, PHD
Five silicone hydrogel contact lens materials
are currently available in the United States and Canada. Each is unique. Compared
to hydrogel lenses, these materials absorb less protein, exhibit increased increased
lipid deposition and display reduced wettability because of the exposure of silicon
groups at the material surface.
Studying Lipid Deposits
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Figure 1.
Lipid deposition as a film on a silicone hydrogel lens.
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Increased lipid deposition with silicone hydrogel lenses is a
clinical complication we need to understand and have a management plan for. You
may see lipid deposition in the form of a heavy film on the lens surface (Figure
1) or as lens calculi "jelly bumps" (Figure 2).
In
2003, Jones and Senchyna reported the degree of lipid deposition on Night &
Day (lotrafilcon A, CIBA Vision), PureVision (balafilcon A, Bausch & Lomb)
and Acuvue (etafilcon, Vistakon) contact lenses. They found that both the lens material
and lipid class influenced the degree of lipid deposition. The two silicone hydrogel
lens materials (lotrafilcon A and balafilcon A) showed significantly higher lipid
deposition as compared to the hydrogel (etafilcon) lens material.
Should we stop using silicone hydrogel lenses because we occasionally
see lipid deposition? No. We believe silicone hydrogel lenses still have many advantages,
but we must learn to manage complications that are unique to this class of lens
materials.
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Figure
2. Lipid deposition as lens calculi on a silicone hydrogel lens. |
How to Manage Lipid Deposits
• Instruct your silicone hydrogel patients to start
rubbing with their no-rub solutions. Corporate marketing departments —
not clinicians — developed the no-rub lens care regimen. The no-rub technique
may be simple and easy, but it's not the most effective method to clean a contact
lens surface.
We instruct all silicone hydrogel patients to rub each lens surface
for 15 to 20 seconds and then to rinse the lens thoroughly before placing it in
disinfection/
storage solution.
• Patients can occasionally use a soft contact lens
surfactant cleaner. One that has alcohol in its formulation can help reduce
lipid deposits on silicone hydrogel lenses. We have found Miraflow (CIBA Vision)
to be an excellent surfactant cleaner.
• Replace silicone hydrogel lenses on a more frequent
basis. Patients tend to stretch the life of their lenses. Make sure they
replace their two-week lenses every two weeks and their monthly lenses every month.
If necessary, consider recommending a more frequent replacement schedule.
• Consider the silicone hydrogel contact lens material.
Each silicone hydrogel material has different characteristics and none show the
same degree of lipid deposition. So, you may need to change the lens material to
reduce lipid deposition.
For references, visit
www.clspectrum.com/references.asp and
click on document #122.
Dr. Ghormley is in private
practice in St. Louis, MO. He is a past president of the American Academy of Optometry
and a Diplomate of its Cornea & Contact Lens Section. He is also a consultant
to CIBA. Dr. Jones is an associate professor at the University of Waterloo School
of Optometry and associate director of the Centre for Contact Lens Research at Waterloo.
Contact Lens Spectrum, Issue: January 2006