Article Date: 2/1/2006

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

S
ilicone 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