We all know that dirty contact lenses are trouble. They blur vision, decrease comfort, and put ocular safety at risk during wear. It is incumbent upon us, as eyecare professionals, to train our patients in proper contact lens care.

FIRST THINGS FIRST

The first step in proper lens care is hand washing. Instructing patients to wash, using soap, and to “rub and rinse” lenses can dramatically reduce the risk of microbial keratitis.¹ Higher frequency of washing has been shown to lower bacterial load on hands.² Emphasize this point to all patients, but particularly to males. A study of university students reported that males wash their hands less often compared to females.³

Proper technique has an impact. One study indicated that 33% of healthcare workers disinfected their hands incorrectly,⁴ most commonly missing the fingertips and thumbs. The Centers for Disease Control and Prevention recommends that hands be scrubbed for at least 20 seconds.⁵

We have observed that many contact lens wearers wash their hands but neglect to dry them afterward, afraid of lint or contamination from the drying towel. This exposes the lens to water, which should always be avoided, according to the U.S. Food and Drug Administration.⁶ Exposure to water can lead to a possible Acanthamoeba infection, a rare but sight-threatening condition,^7-9 so it is important to instruct contact lens wearers to wash their hands and dry them with a clean towel prior to handling their lenses.

Once lenses are applied and removed, what’s next? Daily disposable lenses should be discarded immediately. Re-wearable lenses (e.g., GPs, two-week replacement, monthly replacement, etc.) must be cleaned and then stored in a clean contact lens case. Below are many of the lens care systems that are available today, with some tips on proper use.

GP LENS CARE

All-in-One GP Systems All-in-one GP lens solutions can be used to clean, soak, and wet lenses. According to one manufacturer, its product not only cleans, stores, and conditions GP lenses, it contains a built-in protein remover. At least a four-hour soak is recommended. Though unnecessary prior to lens storage, it is recommended that lenses be rubbed and rinsed after soaking. Another solution is non-abrasive and incorporates hydroxypropyl guar, a viscosity adjuster that is thought to improve lens wetting.

All-in-one GP systems also offer ease and convenience. They can be very effective for those who have good tear quality and are often good for kids due to their simplicity of use. However, some patients require multistep systems to keep lenses clean and comfortable.

Multistep GP Systems Some two-step systems offer both a cleaning solution and a separate conditioning solution. With these products, the cleaner contains silica gel scrubbing beads, which can enhance cleaning but are not recommended for lenses that have plasma or 90% water polyethylene glycol (PEG)-based polymer coating surface treatments. The conditioning solutions are used for both lens storage and wetting prior to application. These particular conditioners are preserved with chlorhexidine gluconate and edetate disodium (EDTA), but a different one in that product line has the added preservative polyaminopropyl biguanide.

Another manufacturer offers three separate solutions. Lenses are stored in that line’s cleaning and disinfection storage solution. In addition, it has an extra-strength cleaner that can be used as needed, depending on how clean the lenses stay with its cleaning and disinfection storage solution. The manufacturer recommends that an extra-strength cleaner be used three or four times per week for patients who are heavy mucous producers. Additionally, its wetting and rewetting drops can be applied to the lens surface immediately prior to lens application or while the lens is being worn.

Protein Removers The choice of a care system for GP lenses can be guided by the lens material. First-generation GP materials were made of silicone and methacrylic acid polymers, known as silicone acrylate lens materials. The silicone added to the material aids oxygen transportation through the lens. However, these materials may have a greater propensity toward protein deposits (Figure 1). Newer fluorosilicone acrylate materials have fluorine added to their matrix, which tends to reduce protein deposition.¹⁰ Protein in tears can also vary with individuals.¹¹

A number of agents are available for protein removal from both GP and soft contact lens surfaces. With one weekly protein remover for GP lenses, at least two drops of the cleaner are instilled in the patients’ lens case containing their habitual contact lens soaking solution. The lenses must soak at least four hours or overnight. Prior to applying to the eye, the lenses must be rubbed, rinsed, and rewet.

Another cleaner that is for GP lens surface protein removal is a mixture of two solutions combined immediately prior to soaking the lenses in the mixture for 30 minutes. Originally an in-office cleaning system, it is now offered to patients for home use every two weeks or as needed. These systems now offer a special, large case for scleral lenses up to 23mm in diameter.

With yet another daily protein remover for soft contact lenses, one drop should be instilled into the soaking solution in each well of the contact lens case, and the lenses should soak at least six hours or overnight. Prior to applying the lenses to the eye, they should be rubbed, rinsed (no tap water!), and rewet.

A final solution is designed to be used once per week in conjunction with a hydrogen peroxide-based disinfecting solution for protein removal from the surface of soft contact lenses.

Lipid Removers Some solutions are meant for in-office cleaning of GP lenses. One solution is comprised of a group of surfactants that can be effective at treating a non-wetting lens surface due to manufacturing residue as well as removing lipids, body oils, and contaminants from personal care products from GP lens surfaces. The manufacturer recommends that, after patients use the in-office cleaner, they should clean their lenses with regular daily cleaner and rub conditioner into the lens surface prior to lens wear.

SCLERAL LENS CARE

Scleral lenses are cared for much like corneal GP lenses, with the addition of a solution needed to fill the bowl of the lens upon application to the ocular surface. Vials of 0.9% inhalation saline have been used off label for filling, but we now have two solutions available specifically for this purpose.

One is a sterile, buffered, isotonic saline solution provided in boxes of 30 10ml vials. The other is a sterile, non-buffered and nonpreserved saline offered in boxes of 98 5ml vials. Scleral lens users can also get a starter kit from one company that contains saline, multipurpose solution (MPS), a deep-cleaning solution, and a case.

HYBRID LENS CARE

Hybrid lenses, featuring a rigid GP center and a soft skirt, should be cared for using either multipurpose solutions designed for use with soft lenses or hydrogen peroxide-based systems. Some patients employing hydrogen peroxide systems may find a white ring develop at the soft/rigid junction, but it does not seem to impact vision or comfort.

Hybrid lenses should be filled with preservative-free saline upon application to the eye to avoid air bubbles. A drop of preservative-free lubricant may be added to the bowl of certain hybrid lenses, if desired.

CARING FOR SURFACE-TREATED LENSES

A poorly wetting GP lens surface can compromise comfort and vision (Figure 2). Fortunately, advancements have been made to improve lens surface wettability.

Plasma Treatment Plasma treatment of GP lenses enhances surface wetting via a two-step process. First, cold gas plasma sterilizes the lens surface by transforming the molecular structure and removing impurities. This is followed by activated oxygen combining with organic surface contaminants, which are then evacuated from the instrument chamber during the plasma process.

Polyethylene Glycol (PEG) A more recent surface treatment is a PEG-based polymer mixture that is permanently bonded to the lens surface.¹² It can be applied to hybrid, GP, and soft contact lens materials. There are several PEG-compatible lens care solutions.

In addition, the manufacturer of the PEG-based surface coating has developed its own care products. One is an MPS for daily cleaning and disinfection that the company says will protect the coating through multiple cleaning cycles. It is scheduled for release during the first quarter of 2018. Another is a proprietary monthly conditioning solution designed to maintain wettability and deposit resistance throughout an entire year’s wearing cycle. It is scheduled for release in the second quarter of 2018.

SOFT LENS CARE

Soft contact lens care systems generally fall into two buckets: MPS and hydrogen peroxide-based systems. Approximately three-quarters (73%) of providers employ MPS care systems as the primary lens care system for their patients.¹³

Disinfectants Polyquaternium-1 (known as PQ-1 or Polyquad) is a bactericidal agent that is a fairly large molecule, making it less likely to penetrate a soft contact lens, reducing its potential to be released and to irritate the ocular surface. Polyaminopropyl biguanide (known as polyhexanide, PHMB, or Dymed) is also bactericidal. It is a derivative of, but much larger than, chlorhexidine. Again, the larger size reduces the likelihood of an adverse tissue reaction. Alexidine is a biguanide molecule that is more hydrophobic compared to PHMB.¹⁴ Myristamidopropyl dimethylamine (known as Aldox) is a cationic agent that fights fungi and amoebae. And, while not strictly a disinfectant, EDTA is often added to care solutions because it enhances disinfection by preventing calcium-bound proteins from depositing on the contact lens surface.

Multipurpose Solutions One manufacturer offers three versions of its MPS solution. They all feature a dual-preservative disinfection system, employing Polyquad and Aldox. Two also have agents added for enhanced moisture retention. Others incorporate EDTA for enhanced disinfection.

Another company developed a revamped MPS that differs from its predecessors in its disinfection system and surface active agents. Rather than the single disinfectant employed by its earlier iterations, the newer one contains a triple disinfection system of polyaminopropyl biguanide, polyquaternium, and alexidine. It also contains two surface active agents—poloxamine and poloxamer 181.

Yet another MPS offers a dual-action disinfection system (polyquaternium and polyaminopropyl biguanide) and hyaluronan (HA) for lubrication.

Two contact lens manufacturers have recently entered the lens care market following the purchase of other companies. Through those acquisitions, one now offers an MPS that has a single preservative, PHMB, while another features a dual-preservative system with polyquaternium-1 and alexidine. In addition, a separate company offers a private-label MPS that employs polyaminopropyl biguanide as its disinfection agent.

The Triad of Compatibility Solution interaction with soft lens material can lead to differences in performance. One study¹⁸ reported differences in protein extraction among four different care systems. Further, the effect was different depending on the lens material (etafilcon A, galyfilcon A, or senofilcon A). The authors observed no consistent pattern. In a subsequent study,¹⁹ no such differences were detected for lipid removal; however, another study²⁰ reported that the amount of cholesterol deposition on lens surfaces is dependent on lens material and lens care solution.

A successful contact lens care system must be compatible with both the contact lens and the patient. MPS systems require some clever chemistry. They must clean and disinfect lenses while being compatible with the lens material and non-irritating to the ocular surface. While today’s systems do an admirable job, sometimes problems will arise.

Here is such a case. A 25-year-old white female employed as a cell culture technician presented reporting that her “right eye tends to get red around the iris.” She further offered that the redness seemed to be associated with contact lens wear and seemed to be worse when at work. She wore silicone hydrogel lenses on a two-week replacement schedule and employed a common MPS for her care. The complaint of unilateral irritation, apparently exacerbated at work, had me concerned about infection secondary to cell culture exposure on the job.

Examination revealed circumlimbal injection of the right eye with a number of corneal infiltrates, mostly in the superior corneal region OD (Figure 3). Although the patient had no complaints with the left eye, examination revealed mild circumlimbal injection and 1+ infiltrates in the superior cornea in this eye as well.

The bilateral slit lamp findings, combined with increasing symptoms with contact lens wear, switched my focus to the contact lens care system. We asked the patient to dispose of her current lenses and to begin wearing a new pair utilizing a hydrogen peroxide-based care system. She returned two weeks later reporting comfortable lens wear and a quiet eye.

RUB, RUB, RUB

No-rub lens care solutions are a thing of the past, fortunately. There is strong evidence that rubbing contact lenses with an MPS, particularly prior to disinfection, has distinct advantages, particularly with silicone hydrogel contact lenses. Rubbing serves to remove deposits¹⁵ and significantly reduces microorganisms on the lens surface.¹⁶

It is recommended that lenses be rubbed for between 5 to 20 seconds or more, depending on the care system. It is also advantageous to rub lenses following disinfection with hydrogen peroxide systems, particularly when used with GP lenses.¹⁷

HYDROGEN PEROXIDE SYSTEMS

Although commonly used as a problem-solver, hydrogen peroxide is often prescribed as a care system of first choice. Three-percent hydrogen peroxide (H₂O₂) is active against bacteria, fungi, viruses, and protozoa.^21-23 It can also penetrate biofilms, unlike many multipurpose solutions. In addition to its effectiveness, it is particularly attractive for patients who have a history of solution sensitivity or dry eye because, following neutralization, no chemical is applied to the ocular surface. Hydrogen peroxide has been shown to be effective in care of all lens types: soft, GP (including sclerals), and hybrid lenses.

One hydrogen peroxide-based system has a platinum disc fixed within the contact lens case that serves to neutralize the hydrogen peroxide over a minimum six-hour soak time. A similar system has a moisturizer added to its formulation, which the manufacturer explains makes it the preferred choice of the two systems for silicone hydrogel materials.

Another hydrogen peroxide-based system employs a neutralizing tablet with a color neutrality indicator as well as the lubricant hydroxypropyl methylcellulose (HPMC). It is indicated for use with soft lenses, but should be avoided with cosmetic lenses manufactured in tefilcon material as it may lead to damage.

While a time-tested method of disinfection that is compatible with virtually all contact lens materials, certain precautions must be taken when employing hydrogen peroxide-based care systems. First and foremost, avoid direct application of active hydrogen peroxide to the ocular surface.

I have had this unfortunate occurrence result not only from forgetful patients, but also from other contact lens-wearing members of the family or visiting friends borrowing the solution, not realizing what’s in it. While the resulting irritation resolves on its own or with some help with lubricants or a steroid drop, it is an unpleasant experience for the sufferer, to say the least.

Also, because hydrogen peroxide’s activity is neutralized overnight, leaving lenses stored in the neutralized solution for extended periods of time is a risk for contamination. However, one manufacturer claims that lenses can be stored in either of its hydrogen peroxide systems for up to seven days, as long as the case remains unopened.

In addition, one recent study found that microorganism load from storage cases after two weeks of use was significantly greater, particularly with Gram-positive contamination, following use of a hydrogen peroxide-based system versus two different MPS systems.²⁴ These findings are consistent with other prior studies.^25-27 To help mitigate this, following lens removal, fill the case with fresh, un-neutralized peroxide and invert the lens case to disinfect the inside cap.¹⁷

CASE CARE

Nasty-looking lens cases are legendary in many eyecare offices, but even mildly used cases can be contaminated. Although replacing the lens case every three months rather than every six months has been shown to reduce the risk of moderate or severe microbial keratitis by 5.4 times,²⁸ another study found that more than 80% of storage cases were contaminated after only two weeks of use.²⁴

Improper care of the lens case can put patients at risk for microbial keratitis at nearly the same rate as sleeping in lenses.²⁹ On a more positive note, it has been found that providing both written and verbal instructions in proper case care (see sidebar on this page) can significantly reduce the rate of case contamination compared to verbal instruction alone.³⁰

COMMIT TO CLEAN

Safe and successful contact lens wear requires a commitment to cleanliness. Clean hands. Clean lenses. Clean cases. Problems with lens solutions and dirty cases can be avoided with daily disposal of lenses, when appropriate. However, clean, dry hands are necessary when handling any contact lenses, regardless of modality. CLS

REFERENCES

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