discovering dry eye
Solving Contact Lens-Induced
Dry Eye With Silicone Hydrogel Lenses
An interview with Kelly Nichols, OD, PhD
BY N. REX GHORMLEY, OD,
FAAO
Silicone hydrogel contact
lenses offer patients better ocular health owing to their high degree of oxygen
permeability. Compared with hydrogel lenses, silicone hydrogels have a stiffer
lens modulus and lower water content. Many clinicians have found that some
silicone hydrogel lenses also reduce dry eye symptoms.
Recently, I discussed dry eye and silicone
hydrogel contact lenses with Kelly Nichols, OD, MPH, PhD. Dr. Nichols is an
associate professor at The Ohio State University College of Optometry. Dry eye
is a research interest of Dr. Nichols and she has received a grant funded by the
National Institute of Health to study dry eye in postmenopausal women.
Advantage: Silicone Lenses
Rex Ghormley (RG): Do patients report
decreased dryness with silicone hydrogel lenses? If so, why?
Kelly Nichols (KN): Schafer and colleagues1
reported decreased dryness with silicone hydrogel lenses; and anecdotal evidence
also supports the hypothesis that silicone hydrogel lenses improve comfort for
many patients.
It's unclear whether all silicone hydrogel lenses
decrease dryness equally due to differences in lens design, modulus, surface
treatment, oxygen permeability and water content.
RG: Schafer1 also reported
dryness symptoms were significantly related to redness and itching symptoms.
Patients with decreased dryness symptoms reported higher levels of contact lens
comfort.
Managing Lipids
RG: Silicone hydrogel lenses have
increased lipid deposition when compared with hydrogel lenses. Does lipid
buildup affect dryness? How do we manage lipid deposition?
KN: Jones and colleagues2
reported silicone hydrogel contact lenses deposit more lipid than HEMA soft
lenses do. As yet, no in-vivo studies of lipid deposition in symptomatic and
asymptomatic silicone hydrogel lens wearers have been performed. Symptomatic
patients with lipid deposition may need to replace their lenses more frequently.
RG: It's also important to instruct
patients to start rubbing with their "no-rub" multipurpose solutions. I instruct
my patients to rub each lens surface for 15 seconds and then rinse the lens
thoroughly before placing it in the disinfection/storage solution.
You also may want to add a good surfactant
cleaner to your patient's lens care regimen. A surfactant cleaner that contains
alcohol can help reduce lipid
deposits on silicone hydrogel lenses. We have found Miraflow (CIBA Vision)
to be an excellent surfactant cleaner.
Rewetting Drops
RG: Are rewetting drops, such as Blink
Contacts (AMO) and Aquify Long-Lasting Comfort Drops (CIBA Vision), effective in
decreasing dryness symptoms with silicone hydrogel lenses?
KN: The data on these products are on file
with the respective manufacturers and not in the literature. However, many
patients adamantly report increased comfort when they use these products. In
addition, studies sponsored by Allergan and Alcon have shown the use of
lubricant eye drops before and after lens wear increases comfortable wearing
time.
This suggests additional lubrication is
beneficial to patients who wear contact lenses, not just silicone hydrogel
lenses, especially if they are symptomatic.
RG: In my experience, both Blink Contacts
and Aquify Comfort Drops are excellent contact lens rewetting drops. Both
contain sodium hyaluronate, an agent that ophthalmic surgeons have used
off-label for many years as a rewetting drop.
Blink Contacts uses Ocupure (stabilized oxychloro
complex) as a preservative, and Aquify Comfort Drops uses sodium perborate
stabilized with phosphoric acid as a preservative.
Lens Care and Dryness
RG: Is there a relationship between
dryness symptoms and the care system used with silicone hydrogel lenses?
KN: Symptoms of dryness can be decreased
in some patients by changing their lens care system. Currently, five solutions
have an FDA indication for silicone hydrogel lenses: Aquify MPS and Clear Care
(CIBA Vision); Opti-Free Express and Replenish (Alcon); and ReNu with MultiPlus
(Bausch & Lomb).
RG: I've noticed some patients have a
reaction to all multipurpose lens care systems. Clear Care or Ultracare (AMO)
hydrogen peroxide-based systems
work very well for these patients. Many patients notice decreased dryness
and whiter eyes with a hydrogen peroxide system.
Therapeutic Lenses
RG: Have you used silicone hydrogel lenses
as bandage lenses for severe dry eye patients?
KN: I haven't had the opportunity to use a
silicone hydrogel lens as a bandage lens; although
I would, given the high
oxygen permeability. We must remember that even a bandage lens must be fit
properly so the increased modulus of the lens material will not cause mechanical
damage.
RG: The FDA has approved only two silicone
hydrogel lenses for therapeutic use: Night & Day (lotrafilcon A) (CIBA Vision)
and PureVision (balafilcon A) (Bausch & Lomb). The therapeutic use of silicone
hydrogel lenses has been a revolutionary development in our ability to manage
recurrent corneal erosions and epithelial dystrophies.
Postmenopausal Dry Eye
RG: Dr. Nichols, you're studying dry eye
in postmenopausal women. In your opinion, will
silicone hydrogel lenses play
a role in relieving these patients' symptoms?
KN: Dry eye is more prevalent in women,
and several studies indicate hormonal changes during and after menopause may
contribute to dry eye. Women who are wearing soft contact lenses and approaching
meno-pause (average age 52) are likely to be interested in bifocal contact
lenses. As a clinician and a scientist, I'm looking forward to the development
of bifocal contact lenses in silicone hydrogel materials. If these materials can
help prevent dryness symptoms, then it's reasonable to expect a silicone
hydrogel bifocal contact lens could help keep these patients from discontinuing
lens wear.
RG: I totally agree. The first company to
develop a good silicone hydrogel bifocal lens will hit a home run.
Bright Future
I'd like to thank Dr. Nichols for contributing to
our knowledge of the dry eye patient and silicone hydrogel lenses. We both agree
this new technology solves many of our patients' physiological and comfort
problems.
I look forward to the many new developments in
silicone hydrogel technology that will be arriving in our offices in the near
future. I believe new advances in silicone hydrogel lens materials and designs,
as well as in rewetting drops and lens care care systems will drive the growth
of the contact lens industry.
Dr. Ghormley
is in a group practice in St Louis. He is a past president of the American
Academy of Optometry and a diplomate of its Cornea and Contact Lens Section. Dr.
Ghormley is a consultant to CIBA Vision.
REFERENCES
1. Schafer J, Barr J, Mack C. A characterization of dryness
symptoms with silicone hydrogel contact lenses. Optometry & Vision Science;
2003. Annual Meeting Abstract and Program Planner accessed at www.aaopt.org. American
Academy of Optometry.
2. Jones L, Senchyna M, Glasier MA, Schickler J, Forbes I,
Louie D, May C. Lysozyme and lipid deposition on silicone hydrogel contact lens
materials. Eye Contact Lens. 2003;29(1 Suppl):S75-S79; discussion S83-S84,
S192-S194.
Contact Lens Spectrum, Issue: February 2006