contact lens care
Caring
for Silicone Hydrogel Contact Lenses — Part 3
BY SUSAN J.
GROMACKI,
OD, MS, FAAO
In parts
1 and
II of this three-part
series, I described the properties of the silicone hydrogel materials and discussed
the lens care systems that the FDA has approved for them. In this column
I'll highlight the known incompatibilities between certain care products and certain
silicone hydrogel materials.
Reported Contraindications
Two care system contraindications
appear on contact lens package inserts:
1. The Advanced Medical Optics
(AMO)
UltraCare Disinfecting System or any of its components (Ultra-care Disinfecting
Solution, Ultra-care Neutralizing Tablets, Lens Plus Daily Cleaner and Ultrazyme
Enzymatic Cleaner) with PureVision (Bausch & Lomb) lenses. NOTE: This precaution
is specific to Ultracare and PureVision. Other hydrogen peroxide systems are acceptable
for use with PureVision and other silicone hydrogel materials. Clear Care (CIBA
Vision) has received specific FDA indication for use with silicone hydrogels.
2. Solo-care
(CIBA) with Acuvue
Advance (Vistakon) lenses. It alters the parameters of this lens. NOTE: The other
polyhexamethylene biguanide (PHMB) systems — ReNu MultiPlus (B&L), Complete
(AMO) and Aquify
MPS (CIBA) — do not cause this effect with Acuvue Advance. Solo-care is no
longer on the market.
Researchers Study Solutions
Although there are many anecdotal
reports regarding silicone hydrogel-solution-cornea interactions, following
are the results from various well-controlled, randomized studies of silicone hydrogel
materials and care systems:
Jones et al (2002) discovered that,
in 50 patients fit with PureVision lenses, 37 percent of patients using ReNu MultiPlus
demonstrated corneal staining consistent with a solution-based toxicity reaction,
while two percent of patients using Opti-Free Express (polyquaternium-1, Alcon)
developed similar staining.
Amos (2004) studied patients wearing
Night & Day (CIBA) lenses and found marginally less overall staining for patients
using AOSept Plus (hydrogen peroxide, CIBA) than for patients using Opti-Free Express.
In addition, no AOSept patients exhibited atypical staining, as opposed to two of
25 (eight percent)
using Opti-Free Express.
Jones (2004) fit 20 lens-related
dry eye patients in both PureVision and Night & Day lenses and alternated each
group with ReNu MultiPlus and AOSept. He found no significant difference from baseline
staining in patients using AOSept, but 47 percent of ReNu-PureVision and 21 percent
of ReNu-Night & Day eyes showed staining.
Lastly, Amos (2004) studied two
PHMB-based regimens — ReNu MultiPlus and Aquify MPS — when used with
Night & Day. At the end of one month, Amos found that 24 percent of the patients
using ReNu MultiPlus exhibited atypical staining, as opposed to none of the Aquify
MPS patients.
Again, this study illustrates that
PHMB is not the real culprit. Rather, it's a more complex solution-material interaction
that we don't yet completely understand.
Don't Assume Anything
The bottom line is, if any unusual
sign or symptom occurs after switching a patient to a silicone hydrogel material,
don't assume the cause is the material alone. Consider a material-solution interaction
and then report your findings. Help us add to the growing body of knowledge concerning
these new materials, the silicone hydrogels.
For
references, visit www.clspectrum.com/references.asp
and click on document #117.
Dr. Gromacki is
in group practice in Burke, Virginia, and has served as a faculty member at
the University of Michigan Department of Ophthalmology and Visual Sciences.
Contact Lens Spectrum, Issue: August 2005