Prescribe appropriate care system based on lens, history and ocular health
When properly used, today’s solutions are designed to safely disinfect and improve comfort.
by Daniella Rutner, OD
This course is jointly sponsored by PRIMARY CARE OPTOMETRY NEWS, The State University of New York State College of Optometry and Vindico Medical Education. It is COPE-approved for 1 continuing education credit.
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Contact lens care is vital to successful contact lens wear. The perfect solution should provide effective, non-toxic disinfection while maximizing comfort. Moreover, it should be quick, simple, easy and inexpensive while being compatible with all contact lens materials.
According to Ky and colleagues, almost eight out of 10 contact lens problems can be linked to improper lens care. Of those patients who discontinue contact lens use, close to 90% do so because of discomfort. This article will attempt to give an overview of current soft contact lens solutions, their indications, advantages, disadvantages and related solution complications.
The primary role of lens care is to disinfect by reducing the microbial load and, thus, the infection risk. According to Efron and colleagues, Poggio and colleagues and Morgan and colleagues, the incidence of microbial keratitis associated with wearing contact lenses is 3.5 to 14 cases per 10,000 individuals for daily wear hydrogels and 20 to 144.6 cases per 10,000 individuals for extended wear hydrogels.
Several sources of bacterial infection are associated with contact lens contamination: poor lens handling, failure to wash hands or poor personal hygiene, and poor lid hygiene. Fungal infection should be suspected when a history of exposure to vegetative matter exists. A viral infection can be acquired while handling a lens during the acute phase of an upper respiratory infection, while Protozoa infections, such as Acanthamoeba, are associated with showering or swimming while wearing lenses or using tap water to rinse them.
Lens care enhances comfort
The secondary and more current role of lens care is to enhance lens wear comfort. Comfort is improved by removing hydrophobic lens deposits (e.g., lipids) and proteins, as well as by increasing lens viscosity and hydration.
Excess lipid deposits on the lens result in poor surface wetting, which inhibits the lubrication between the cornea and the upper lid, reducing comfort. Moreover, the effect of lipid deposition on surface wetting creates an irregular pre-lens refractive layer that reduces visual acuity. Although proteins exist naturally in the tear film, once they denature, that protein contributes to the autoimmune/mechanical giant papillary conjunctivitis (GPC) response.
Current chemical soft lens care products contain one or more viscosity- and hydration-enhancing agents to reduce symptoms related to lens dryness, especially toward the end of the day. Surface wetting is highly dependent on not only the hydrogel material but also the contact lens solution and the interaction of the two.
First lens cleaner: heat
Among the early contact lens disinfection processes, heat was considered the gold standard. Used daily, this method is effective against all microbe classes. A key limitation is that the extreme heat required, between 80°C and 100°C, results in protein denaturation. This method is incompatible with newer lens materials.
The first-generation cleaners featured a two-step process: a cleaner, which required rubbing, and a disinfecting solution. The solution contained either the preservative thimerosal, a mercury-based compound with a high incidence of allergic response, or benzalkonium chloride, which although commonly used in ophthalmic drugs, has a high incidence of toxic reactions. It also carries the potential for superficial punctate keratitis with prolonged use.
The second generation of soft contact lens cleaners is the multipurpose cleaner (MPS), which includes a cleaner, saline and disinfectant in one solution. These cleaners still require rubbing as part of overall disinfection. They contain larger molecules that reduce the amount of solution the lens absorbs, thus reducing toxicity risk. In addition, they also require a separate weekly protein cleaner. Two brands are still on the market — Opti-Free (Alcon Laboratories, Fort Worth, Texas) and ReNu (Bausch & Lomb, Rochester, N.Y.).
MPS products work well for most patients who use 2-week and monthly disposable soft lenses. However, patients who replace their lenses less frequently and occasionally even disposable lens wearers with heavy lens deposits, need a stronger, separate cleaner.
Multipurpose disinfecting solutions
The labeling criteria for multipurpose disinfecting solutions (MPDS) are more stringent than for MPS labeling. MPDS systems must meet the primary criteria of the stand-alone test, which requires a higher efficacy level. These third-generation contact lens solutions have the “no rub” label due to either their increased disinfectant level or an additional disinfecting agent. In addition, surfactants have been added to help remove debris during rinsing. It is imperative that the patient rinse the lenses prior to putting them into the lens case.
Two MPDS solutions are currently available. Opti-Free Express uses Polyquad and Aldox for disinfection, which takes 4 hours. It also contains Tetronic for hydration. The ReNu MultiPlus uses Dymed as the disinfecting agent. The process is complete after 4 hours of soak. This solution is not approved for use with silicone hydrogels, as several studies reported an increased risk of punctate staining with silicone hydrogels.
According to Beattie and colleagues, while both Opti-Free Express and ReNu MultiPlus effectively disinfect Acanthamoeban trophozoites, ReNu MultiPlus is better at killing the cyst form of Acanthamoeba in a 24-hour period.
Fourth-generation cleaners
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The fourth generation of MPS surface active agents and hydrophilic agents attract more tears and enhance their adherence to the lens surface to reduce lens dryness symptoms.
Opti-Free Replenish offers a 6-hour disinfection time. The cleaner disinfects with Polyquad and Aldox and has a citrate cleaning agent. It contains the surfactant agent Tetronic1304 and a hydrophilic agent, Tearglyde (C9-ED3A). It is labeled for use with all silicone hydrogels.
These agents recondition the lens surface during each overnight soak, attracting more tears to the lens surface to improve comfort and visual acuity.
When Stiegemeier and colleagues compared various solutions, the wetting agent Tetronic was the only solution that continued to give Group IV lenses comfort through 8 hours of wear.
Replenish also incorporates propylene glycol, a demulcent, to enhance wetting and comfort. It requires a 5-second rinse on each side or a digital rub as directed by the practitioner. Rubbing is especially important with silicone hydrogels. If using in conjunction with Opti-Free Supraclens daily protein removal, the patient must rinse the lens prior to insertion. Lenses can be stored for up for 30 days.
Aquify Multi-Purpose Solution (CIBA Vision, Duluth, Ga.) uses the disinfectant polyhexanide but requires a digital rub with a minimum of three drops on each side of the lens followed by a rinse and a 4-hour soak. It contains the surfactant pluronic F127 and the hydrophilic agent dexpanthenol. It is labeled for all silicone hydrogel materials.
AMO (Santa Ana, Calif.) recalled its Complete MoisturePlus in response to data from the U.S. Centers for Disease Control and Prevention showing an increased risk of Acanthamoeba keratitis associated with its use, the company announced on May 25.
Complete MoisturePlus was the only solution to contain the non-surfactant viscosity agent hydroxypropyl-methylcellulose, which has been clinically shown by Larsen and colleagues to affect the comfort of Group IV lenses, and the hydrophilic agent propylene glycol.
Complete MoisturePlus was also the only contact lens solution containing the amino acid taurine, which Thimons showed to inhibit protein denaturation and possibly decrease protein binding to contact lenses, thus improving comfort and reducing associated GPC risk. This solution was not approved for use with silicone hydrogels.
ReNu with MoistureLoc was recalled in April 2006 when it was linked to Fusarium keratitis, although the cause is unclear. Patients sometimes misuse contact lenses or cleaning procedures. It is unclear how and if the misuse of ReNu with MoistureLoc caused a unique susceptibility to fungal infection.
The disinfectant in ReNu with MoistureLoc is alexidine. It is possible that under certain circumstances, this disinfectant allows fungus to survive on a contact lens or in the storage solution. It is also possible that the polymers responsible for comfort encourage fungal growth.
Hydrogen peroxide systems
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Another category of lens care is hydrogen peroxide. Peroxide systems minimize the potential for sensitivity reaction and they have a greater antifungal action than any chemical system.
AOSept (CIBA Vision), a three-bottle system, is the original one-step peroxide system. MiraFlow, an isopropyl alcohol-based daily cleaner, emulsifies lipids and provides some disinfection. The saline rinse removes the MiraFlow. The peroxide disinfection solution with neutralization, performed with a platinum-coated plastic disc, takes 6 hours to complete. Once disinfected, patients can safely store lenses for 7 days.
UltraCare (AMO) is a three-bottle system: Lens Plus Daily Cleaner, Lens Plus Sterile Saline (to rinse off the daily cleaner) and hydrogen peroxide. Neutralization is complete in 6 hours with the aid of a catalyst. This system has a wetting agent (hydroxypropyl methylcellulose) in the neutralization tablet. It is recommended that the lens not be rinsed prior to insertion to take advantage of the built-in lubricant. The maximum storage time is 7 days. UltraCare is contraindicated with Bausch & Lomb PureVision lenses.
The Clear Care system (CIBA Vision) combines a cleaner, Pluronic 17R4 and 3% H2O2 in one bottle. With a 5-second rinse, it is Food and Drug Administration approved for no rubbing. Neutralization is completed in 6 hours using a platinum disc catalyst. Once disinfected, the lenses can be stored 7 days before repeat disinfection is necessary.
The platinum-coated plastic disc in this one-step system catalyzes the breakdown of the hydrogen peroxide to oxygen and water. Depending on the age of the disc, the neutralization may occur in a few minutes or in several hours. A fresh disc neutralizes peroxide quickly, thus rapidly decreasing the concentration and contact time for antimicrobial activity while providing a more thorough neutralization. An old disc provides a longer contact time with higher peroxide concentrations but with less effective neutralization.
Patients should use caution with this system, however, because as the disc ages, the residual peroxide level increases. Moreover, because the Clear Care cannot be used directly in the eyes, it requires a saline rinse before insertion. It is the only peroxide system indicated by the FDA for silicone hydrogel lenses.
Sauflon One Step (Sauflon Pharmaceuticals, Hicksville, N.Y.) is the newest offering. A one-bottle peroxide system, Sauflon One Step contains a built-in cleaner and has no-rub approval with a 5-second per side (20 seconds total) rinse prior to disinfection.
It is the only one-bottle H2O2 system with a rewetting agent, which is important for dry eye patients. Neutralization with the catalytic disc takes 6 hours; storage time should not exceed 24 hours before re-disinfecting.
Contact lens reactions
Symptoms of contact lens reaction may include burning, itching, redness and tearing. If symptoms are greatest upon lens insertion it can be secondary to chemical/peroxide sensitivity. If the symptoms are acute and severe it is likely that the patient failed to appropriately neutralize the lenses prior to insertion or inserted the peroxide directly into the eye. The symptoms may take weeks or even months to appear. In addition to the patient’s subjective symptoms, diffuse punctate keratitis is observed typically affecting central cornea last.
Solution-related infiltrates are multiple, small, diffuse, sterile and commonly seen bilaterally, presenting non-specific inflammatory processes. A patient will respond quickly if he or she stops using contact lens solution and uses a steroid. If the patient returns to habitual contact lens care, the symptoms will recur.
Superior limbic keratoconjunctivitis remains associated with MPS even though thimerosal, the most common culprit, is no longer used. Patients have superior bulbar hyperemia, staining and hypertrophy of the superior tarsal conjunciva. Symptoms include burning, photosensitivity and decreased wearing time.
Pseudodendritic keratitis is associated with contact lens solutions. It can occur centrally or peripherally but is rarely present with staining, and corneal sensitivity remains intact.
When managing contact lens solution complications, the patient should discontinue the current care system and regimen. When the complication clears, resume with a new and different lens care system.
As clinicians, it is our obligation to “prescribe” the most appropriate lens care system to our patients based on their contact lens, history and ocular health.
For more information:References:
- Daniella Rutner, OD, is an assistant clinical professor at the University Optometric Center of New York. She can be reached at 33 West 42nd St., New York, NY 10036; (212) 938-5834; fax: (212) 938-5760; e-mail: drutner@sunyopt.edu. Dr. Rutner has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.
- Beattie TK, Seal D, Tomlinson A, et al. Determination of amoebicidal activities of mutipupose contact lens solutions by using a most probable number enumeration technique. J Clin Microbiol. 2003;41:2992-3000.
- Efron N, Morgan PB, Hill EA, et al. Incidence and morbidity of hospital-presenting corneal infiltrative events associated with contact lens wear. Clin Exp Optom. 2005;88:232-239.
- Fonn D. Preventing contact lens dropouts: Addressing issues of discomfort, inconvenience and dryness may keep more patients in contact lens wear. Contact Lens Spectrum. 2002;17:26-32.
- Grus FH. Measuring tear film integrity: Can lens care solutions change the protein composition of the tear film in contact lens wearers? New analytic technology is helping answer this question Contact Lens Spectrum. 2005 Supplement 6-8.
- Ky W, Scherick K, Stenson S. Clinical survey of lens care in contact lens patients. CLAO J. 1998;24:216-219.
- Larsen S, Smith C, Mathis J, et al. Comfort differences between multi-purpose solutions. Contact Lens Spectrum. 2002;12:40-43.
- Morgan PB, Efron N, Hill EA, et al. Incidence of keratitis of varying severity among contact lens wearers. BJ Ophthalmology. 2005;89:430-436.
- Poggio EC, Glynn RJ, Schein OD, et al. The incidence of ulcerative keratitis among users of daily-wear and extended-wear soft contact lenses. N Engl J Med. 1989;321:779-783.
- Stiegemeier MJ, Friederichs GJ, Hughes JL, et al. Clinical evaluation of a new multi-purpose disinfecting solution in symptomatic contact lens wearers. Contact Lens Anterior Eye. 2006;29:143-151.
- Thimons J. Ocular health and next generation solutions: Understanding taurine and its possible role in ocular health. Contact Lens Spectrum. 2004 Supplement 4-5.
- Wei-Boon Khor, Aung T, Saw SM, et al. An outbreak of Fusarium keratitis associated with contact lens wear in Singapore. JAMA. 2006;295:2867-2873.