GP LENS CARE
Proper Care of Modern GP Lenses
Educate your patients about materials, solutions, and cleaning and disinfecting procedures.
By Douglas P. Benoit, OD, FAAO
Over the years, much has been written about the demise of GP contact lenses (Efron, 2010). Thankfully, such predictions have not come true. If anything, GP lens use is on the rise, although it is a gentle slope.
Part of this is due to design changes for multifocal lenses that have increased visual performance and diminished physiologic compromise (think corneal molding). Another reason for interest in GP lens use is the redevelopment of scleral lens designs. This segment seems to be growing at the fastest rate of all GP lenses.
Along with these design enhancements, material technology has improved as well. We have increased oxygen permeability (Dk) and transmissibility (Dk/t), various refractive indexes, and plasma treatment. These various innovations have improved the vision with GP lenses, particularly multifocal contact lenses.
The increased oxygen flux is important for scleral lens designs because they tend to move very little on the eye, which results in low tear exchange. The tears already have a lower Dk compared to the GP material, so maximizing the oxygen permeability of the material is critical to maintaining corneal health.
Lastly, we can thank improved care systems that make cleaning and care easier and keep lenses feeling more comfortable. Our care solution choices are better. In addition, the systems, for the most part, are also easier for patients to use.
Modern GP Materials
In this article, we will define modern GP materials as fluorosilicone/acrylate polymers that have a Dk above 50. There are many of these materials available, and new polymers are being developed. The goal is a material that does not harm the ocular surface, nor disrupt the physiology of the eye, yet can provide crisp vision and good comfort all day long.
Newer materials also have the advantage of plasma treatment. This cleans off non-organic contaminants and increases surface wettability by decreasing the wetting angle. These treatments get into the material very slightly. Depending on the material and plasma treatment combination, the effect will wear off after two to six months. Abrasive cleaners disrupt the treatments, but alcohol-based cleaners do not seem to have a negative effect (Martin, 2015).
Tap Water Use and/or Exposure There has been much attention paid recently to the use of tap water with regard to contact lenses (Shoff et al, 2008; Butcko et al, 2007). For many years, tap water has been used to rinse the cleaner off of GP lenses prior to disinfecting and storing them. While the incidence of problems has been low, poor patient compliance with proper cleaning technique and hygiene has created an environment in which the risk of infection is simply too great. In fact, most recently, the U.S. Food and Drug Administration (FDA) has stated: “Do not expose your contact lenses to any water: tap, bottled, distilled, lake, or ocean” (Ward et al, 2015).
Therefore, it is prudent to advise patients to avoid water exposure. This includes drying the hands thoroughly before handling the lenses as well as not rinsing lenses (or lens cases) with water. Fortunately, there are modern GP lens care solution choices that do not need a water-type rinse.
Another possible risk of contamination from water exposure comes from showering and/or swimming with contact lenses on the eye. Again, avoiding such activities is probably the best approach. However, if it occurs, the conventional wisdom dictates that the lenses be removed as soon as possible and cleaned and disinfected appropriately prior to wear.
Solution Confusion GP lens care products have evolved tremendously over the years. There are one-bottle systems now that allow cleaning, rinsing, disinfecting, and rewetting with a single solution. These products remove debris and protein as well as condition the surface for enhanced wettability and comfort during wear.
Any all-in-one product will need to have preservatives, and some patients may have sensitivities to these preservative agents or to other ingredients in the formulation. Thus, caution is a must when prescribing multipurpose GP care solutions.
Some solutions in systems that provide cleaning, disinfecting and wetting/rewetting also must be rinsed off prior to application. They will cause redness and irritation if they get into the eye. This type of solution could be rinsed off with saline or rubbed and rinsed with the wetting/rewetting (WRW) solution. The latter process is less cumbersome for patients and works very well. For those times when tougher cleaning action is required, the system has an extra strength cleaner (ESC) that also needs to be completely rinsed away prior to applying the lenses with the WRW solution.
Alcohol-based cleaning agents do a wonderful job of removing debris and killing contaminating organisms. They are gentle on the lens surface and usually do not harm plasma treatments. They do need to be rinsed off or they will burn and irritate the ocular surface. When properly rinsed off, however, these products should cause no sensitivity reactions.
Peroxide-based cleaning/disinfection systems have evolved and are approved for use with GP materials. These products can penetrate biofilm and seem effective against Acanthamoeba cysts and trophozoites (Hiti et al, 2005).
It is important to note that not all solutions are created equal. In my opinion, branded products are often superior to generic solutions. This is because many generic solutions are actually older formulations that may not be compatible with modern GP materials. Therefore, the rationale for recommending the use of a particular regimen should be discussed with each patient.
Proper cleaning technique needs to be demonstrated at the dispensing visit and reinforced at all follow-up visits. At the yearly eye examination, patients should be quizzed on what solution they are using and how they are using it.
To Enzyme or Not An area that generates many questions, particularly among long-term lens wearers, is whether or not to enzyme the lenses. Enzyme cleaners were introduced to remove denatured proteins from soft contact lenses. After a time, it was thought that these protein removers could be beneficial for GP lenses as well. However, most GP lens patients probably do not need an enzymatic cleaner because they simply are not depositors. The newer care systems also seem to do a good job of removing the debris and deposits from the lens surface, when used properly.
For patients who seem to have buildup on their lenses despite good daily cleaning, Progent (Menicon) may be a better alternative compared to enzymes. The product is produced by mixing Progent A (sodium hypochlorite, sodium carbonate, sodium hydroxide, purified water) and Progent B (potassium bromide, sodium carbonate, purified water) solutions in a specially designed vial. Progent was recently approved for patients to use at home. It had originally been limited to in-office use by eyecare professionals. The reason for some hesitation in allowing patients to use it at home is because the product is basically a bleach solution.
When performed properly, the 30-minute soak removes built-up deposits and protein. The combined solution is then discarded, and the lenses are rinsed in the vial with Progent Rinsing Solution. Once completed, the vial is air dried until the next application. The lenses will need to be cleaned and disinfected using the patients’ daily care products.
The Lens Case Case contamination has been shown to be one of the biggest risks for ocular infection (Tilia et al, 2014; Wu et al, 2010). It is critical that the lens case be air dried while the lenses are being worn.
In the past, the case would have been rinsed with tap water and left open to dry. As stated earlier, the FDA has advised against exposing contact lenses to tap water. That statement, along with the work of Shoff et al (2008), would indicate that the case should also be rinsed with something other than tap water. Using more disinfecting solution is one option, but simply wiping the case with a towel or tissue and allowing it to air dry would seem as safe and sensible.
Prior to Dispensing
In the past, it was common practice to inspect all lenses received from the laboratory to be sure that the parameters ordered were met. With the advent of modern, computerized lathing equipment, such inspection is less necessary. And, with the wet shipping of plasma-treated lenses, inspection may be unwise, unless caution is taken. For those who choose to inspect/verify each lens (strongly suggested), there should be a standard cleaning and disinfecting protocol implemented post-inspection.
Using an alcohol-based cleaning agent is a good first step. Rub each lens for approximately 10 seconds, either in the palm of the hand or between the fingers. Next, the cleaner must be thoroughly rinsed from the lens. Do this by rubbing the lens with sterile saline until it feels squeaky clean. Lastly, disinfect the lenses with a straight disinfecting agent, like one of the peroxide-based systems, or with a disinfecting/soaking solution for GP lens materials. As always, it is best to rub on some wetting solution prior to application.
One of the best ways to prevent problems associated with contact lens wear is to educate patients with regard to proper techniques for cleaning, rinsing, and disinfecting their lenses. During this discussion, be sure to tell patients why each of these steps is necessary, not just how to do them. People, in general, seem to comply better when they understand the rationale for performing a particular task.
Handling As always, prior to handling the lens, hands must be washed and dried thoroughly. Again, explain why drying is necessary, and that water exposure could be problematic.
Cleaning No matter what cleaning and disinfecting regimen you choose, review the instructions with patients. Staff members can be used here, but they must deliver a consistent message. Also, it should be in line with the solution package insert.
Cleaning is best done when the lenses are removed at the end of the day because the debris that has accumulated is fresh and easier to remove. Three or four drops of the cleaning solution should be applied to the lens. The lens then needs to be gently rubbed for about 10 seconds.
Rinsing Next, the lens needs to be rinsed with the appropriate solution. It could be rinsed with saline if an alcohol-based cleaner was used, or it could be rinsed with more of an all-in-one product. For rinsing off alcohol-based cleaning agents, it is wise to rub the lens as it is rinsed to ensure that the cleaner is truly removed.
Disinfecting After a thorough cleaning and rinsing, the lens is ready to be disinfected. With the multipurpose GP solutions, the lens can simply be put into the lens case with fresh solution. The lenses can soak overnight, but again follow the manufacturers’ package insert with regard to minimum and maximum soak/disinfection times.
In a system that uses a separate cleaner and disinfecting agent, the approach is the same unless your patient is disinfecting with a peroxide-based system. In this instance, a defined cleaning step may be used (with a rinse), or the lenses can go straight into the lens holder.
With the latter approach, the lens holder/lenses are then rinsed in a stream of the peroxide product prior to being placed in the filled disinfection cup. Remind patients not to shake the container. That action could result in non-neutralized peroxide contacting the lenses, or fingers, and ending up in the eye when the lenses are used next.
Reapplication Prior to the next wearing of the cleaned and disinfected lenses, your patients’ hands must be washed and dried. Then, the lenses can be removed from the disinfection cup or case and applied to the eyes. The choice of adding a drop of conditioner prior to application is an individual decision. Once the lenses are on eyes, the case needs to be emptied of solution and dried with a towel or tissue. The lens case could be rinsed with fresh solution prior to the drying phase, but it should never be rinsed with tap water. The lens case needs to air dry during the wearing day.
Patients receive a great deal of information at the dispensing visit, especially new wearers. It is easy to understand why some patients find it difficult to remember the proper procedures. To make it easier, give patients a printout of their cleaning regimen as a home reference.
As mentioned earlier, it is important to review the care of the lenses, as well as the solutions that they are using, whenever patients are in the office. This gives eyecare professionals the opportunity to reinforce the reasons for proper cleaning and disinfection. It also provides the opportunity to ensure that patients are using the correct care solutions. Further, this impresses upon patients that caring for their contact lenses is a serious business designed to allow years of problem-free wear. CLS
For references, please visit www.clspectrum.com/references and click on document #234.
Dr. Benoit is the senior optometrist with Concord Eye Center, a multi-subspecialty ophthalmology group in Concord, NH. He is a Fellow of the American Academy of Optometry and a Diplomate of the Section on Cornea, Contact Lenses and Refractive Technologies. He is currently the Special Advisor for the Section. Dr. Benoit is a Distinguished Practitioner and Fellow in the National Academies of Practice-Optometry Section and is a Diplomate of the American Board of Optometry. He is also on the Advisory Board of the Gas Permeable Lens Institute. Dr. Benoit is a consultant to, and clinical investigator for, Alcon.