contact lenses

Care Impacts Successful Wear

Why it's critical to take an active role in your patients' contact lens care regimen.

Gina Wesley, O.D., M.S., F.A.A.O.
Medina, Minn.

The recent recalls of several contact lens solutions have had a tremendous impact on our solution paradigms. Today, the process behind solutions' approval and how they meet safety standards is complex, although necessary for our understanding of what is best for the patient. Why? Solution “recommendations” aren't enough anymore. Today, you, as the optometrist, must comprehend solution efficacy, what to prescribe for contact lens care and why.

Staying current

We need to familiarize ourselves with all contact lens solutions, as patients often ask questions about these products and/or are using these products outside of our prescribed regimens.

Most contact lens wearers don't worry about disinfecting issues. In large part, this is thanks to the extensive FDA approval process for any solution. Both the FDA and the International Organization for Standardization (ISO) have developed performance criteria by which contact lens solutions are measured. The ISO has published Ophthalmic optics—Contact lenses and contact lens care products—Fundamental Requirements, which specifies safety and performance requirements for contact lenses and contact lens care products.¹

In 1997, the FDA published guidance documents for contact lens care products, which provides the minimum acceptable reduction of standard “challenge” organisms.² The reduction is measured by log reductions—one-log reduction means 90% of the organism is reduced, which is the standard for fungi (Fusarium solani and Candida albicans). Bacteria (Serratia marcescens, Pseudomonas aeruginosa and Staphylococcus aureus) must be reduced by a 3-log reduction, or 99.9%, according to the FDA published guidance documents for contact lens care products.

Currently, ISO standards do not require testing against Acanthamoeba. In addition, the FDA has no performance standards for Acanthamoeba reduction by a contact lens solution. However, the FDA is currently researching Acanthamoeba with the intention of eventually including it as a test organism.³ At this time, hydrogen peroxide solution systems seem to have the best disinfection capability in this arena.⁴

While all manufacturers' contact lens solutions meet the minimum log reduction standards set by the FDA, a chart published in Contact Lens Spectrum (February 2010) shows reduction rates for each organism vary from solution to solution.⁵ However, these tests are conducted in vitro. What happens once you introduce a contact lens? The answer lies not only in looking to our past mistakes, but in continuing to demand safe and effective solutions for our patients now and in the future.

Science behind the solution

Today's multi-purpose contact lens solutions (MPS) are comprised of cleaners/surfactants, which maintain a clean surface, as well as antibiotic preservatives and buffers.⁶ Solutions also require lubricants, or wetting agents, to decrease the wetting angle and enhance lens comfort for the patient. It's been positioned that preservatives have been the culprits in some solution recall issues, as molecular weights have varied amongst them. The changes in weight caused interactions with new lens materials and possibly decreased disinfection efficacy, the manufacturers of these solutions have said. Wetting agents, as well, have been suspected to harbor opportunistic microbes in patient conditions stemming from non-compliance.

Due to recalls of MPS systems, hydrogen peroxide solutions have gained market share. These systems penetrate the matrix and oxidize microbes. This chemistry enables further breakdown of protein and lipid bonding to the lens.⁶ Another advantage of hydrogen peroxide is its ability to penetrate microbial biofilms, which is difficult for most MPS solutions.

Hydrogen peroxide systems are preservative-free, although the solution must be neutralized before placing lenses on the eyes. These mainstays of contact lens care systems have met, with mixed results, the challenge of cleaning and disinfecting the newest contact lens material, silicone hydrogel. Several studies have shown increased incidence of corneal staining associated with various care systems in combination with silicone hydrogel materials.⁷ What this staining means clinically continues to be under investigation.

Manufacturers have re-formulated several MPS systems in an attempt to improve their compatibility with the new lens materials and decrease the potential of corneal staining and infectious complications. The wetting of these lenses has proved the biggest challenge and have garnered re-formulated solutions aimed to create a moisturized lens for the patient. However, adverse events with Fusarium and Acanthamoeba keratitis have resulted in the recall of a couple of these solutions.⁸

By comparison, hydrogen peroxide systems have resulted in low amounts of corneal staining. Although potentially not as convenient or economical to use as MPS systems, these solutions have shown to be a viable option for patient lens care.⁹

Meeting today's technology

With the rise of silicone hydrogel technology, it's clear that solutions must be compatible with these materials and not the other way around. As mentioned, wettability is the biggest obstacle to successful contact lens wear in these materials. One recent study revealed that various silicone hydrogel materials had large differences in wetting properties when taken directly from the lens pack.¹⁰ Surface modifications of these lenses helped improve wettability, but at what cost to solution disinfection capabilities?

A study of MPS and hydrogen peroxide systems demonstrated that both can be viable cleaning and disinfection options for silicone hydrogel lenses.⁸ In this study, an MPS and a hydrogen peroxide solution were compared using silicone hydrogel materials. The results of the study imply that the hydrogen peroxide system could provide longer wear times than the MPS solution. However, in another study, the MPS solution improved wettability.¹⁰ The solid conclusion is that further research is needed to determine what solution is best for particular silicone hydrogel contact lenses.

Guidelines for compliance

In light of past issues, follow these guidelines to help patients improve contact lens care compliance:

1. Discuss solution and lens compatibility with patients. Utilize clinical observation and patient subjective reports to determine clinically effective solution options.
2. Present specific instructions for each contact lens patient on how exactly you want them to care for their lenses. Review this at every examination and not just with brand-new wearers. Also review the consequences of not following instructions, such as risk of infection, corneal infiltrates/ulcers, and the worst case, vision loss.
3. Instruct patients to add a rub step to the cleaning regimen, even with peroxide systems, as doing so helps to reduce deposition and resultant biofilms.⁶ This, in turn, can help reduce risk for microbial complications as well as be more economical for the patient, in terms of solution usage, compared with past no-rub regimens.
4. Evaluate corneal staining in each and every one of your contact lens patients. Staining may indicate solution/lens material incompatibility. Clinically significant corneal staining should not be accepted as the “norm” for ocular surface findings.
5. Include with your contact lens prescription the appropriate solution that will keep patients safe, comfortable and successful in their everyday contact lens wear.
6. Instruct patients not to substitute generic/private-label MPS solutions, as these do not carry formulations indicated by the FDA for use with silicone hydrogel lenses. Until we have comprehensive data on care systems and their compatibility with silicone hydrogel materials, it's imperative we follow this step.

Follow-up with patients to ensure they are using your prescription guidelines for contact lens care systems can be as simple as a phone call or e-mail from you or your staff. Use digital technology to send periodic reminders as to the how and why of your prescribed regimens. Of course, in-office education during any contact-lens related visit is also a great way to continue to direct your patients.

The world of contact lens technology and its accompanying care systems is dynamic and ever-changing. Fortunately, that usually means patients and practitioners benefit in terms of performance and overall satisfaction. It is our job as primary eye care providers to stay abreast of recent findings and tests so clinically sound, evidence-based decisions and prescriptions for lens care can be made regarding each and every patient in the exam room chair. OM

1. ISO website. Ophthalmic optics—Contact lenses and contact lens care products—Fundamental requirements. www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=31778. Accessed March 2011.
2. FDA/CDRH website. Premarket Notification FDA (510{k}). Guidance Document for Contact Lens Care Products. www.fda.gov/downloads/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/UCM080218.pdf. Accessed February 2011.
3. Contact Lens Spectrum. Gromacki, SJ. An Update on Regulatory Changes for Lens Care Systems. www.clspectrum.com/article.aspx?article=105190. Accessed March 2011.
4. Johnston SP, Sriram R, Qvarnstrom Y, et al. Resistance of Acanthamoeba cysts to disinfection in multiple contact lens solutions. J Clin Microbiol. 2009 Jul;47(7):2040-5.
5. Contact Lens Spectrum. Melton R, Thomas R, Snyder C. Methicillin-resistant Staphylococcus aureus in Eyecare and in the Contact Lens Practice. www.clspectrum.com/article.aspx?article=103932. Accessed March 2011.
6. Wolters Kluwer Health. Gromacki SJ. Hydrogel and Silicone Hydrogel Lens Care. www.visioncareeducation.com/no-feece/course1.asp Accessed March 2011.
7. Garofalo RJ, Dassanayake N, Carey C, et. Al. Corneal staining and subjective symptoms with multipurpose solutions as a function of time. Eye Contact Lens. 2005 Jul;31(4):166-74.
8. Keir N, Woods CA, Dumbleton K, Jones L. Clinical performance of different care systems with silicone hydrogel contact lenses. Cont Lens Anterior Eye. 2010 Aug;33(4):189-95.
9. Efron N. Morgan PB. Soft contact lens care regimens in the UK. Cont Lens Anterior Eye. 2008 Dec;31(6):283-4.
10. Ketelson H, Meadows D, McQueen N, Stone R. Wettability of Silicone Hydrogel Lenses in the Presence of Tear Components. RCCL. April 2005;3(142):24-8.

Dr. Wesley practices primary eye care optometry, emphasizing on contact lenses. She regularly lectures to optometrists, paraoptometrics and students. In addition, Dr. Wesley was recently awarded the 2011 Minnesota Young Optometrist of the Year award. E-mail comments to optometricmanagement@gmail.com.