Contact Lens Care Update
A comprehensive look at new products, what lens types they work with and much more.
By Long Tran, OD, & Eunice Myung, OD
Successful contact lens wear depends heavily on contact lens comfort. The abundance of contact lens care systems and rewetting agents available on the market warrants a closer look into what these products claim to do. Let's review some newly released care systems and rewetting agents and look at what we should consider when making recommendations to our contact lens patients.
Soft Lens Care Systems
Not long ago, the goal of a soft lens care system was simply to clean and disinfect the contact lens. With discomfort continually being the number-one reason for contact lens dropouts, a new generation of multipurpose solutions (MPSs) now aims to clean, disinfect and moisturize. CIBA Vision, Bausch & Lomb (B&L) and Advanced Medical Optics (AMO) have all recently introduced new lens care systems that target these goals. They aim to deliver increased comfort and prolonged lens wearing time. Based on early patient feedback, these care systems seem promising.
Aquify 5 Minute MPS In August 2004, CIBA Vision released this product, which contains a new formulation called Hydrolock. According to CIBA, Hydrolock increases lens moisture and decreases ocular evaporation.
The main moisturizing agents in Aquify are Dexpant-5 (dexpanthenol) and Sorbitol, which is a natural humectant (moisturizer). Sorbitol acts to moisten the lens, while Dexpant-5 moistens and slows evaporation. Other active ingredients act to loosen and remove protein deposits during soaking. Advertised as the quickest acting MPS on the market, the FDA has approved Aquify for cleaning and disinfecting with either a simple, 10-second rub and a five-minute soak or a five-second rinse and a four-hour soak.
ReNu with MoistureLoc MPS In September 2004, B&L launched ReNu with MoistureLoc MPS to replace ReNu MultiPlus MPS No Rub Formula. According to the company, ReNu with MoistureLoc increases water retention by creating a long-lasting "cushion" of moisture. The new MoistureLoc formulation contains two synergistic polymers that bind and retain moisture:
- Polyquarternium-10 has a "cellulosic" backbone that binds to the lens surface and draws in water. It creates a scaffolding for Poloxamer 407 to bind to and draw more moisture to the lens.
- Poloxamer 407 also works with Hydranate to encase proteins, keeping them in a stable, native state and away from the lens surface. The cleaning regimen for ReNu with MoistureLoc has remained unchanged, where patients follow a five-second rinse with a four-hour soak.
Complete MoisturePlus Completing the trio of new MPS systems is AMO's Complete MoisturePlus No-Rub MPS. Like the two lens care systems previously mentioned, Complete MoisturePlus MPS has a new "anti-dryness" formulation. However, Complete MoisturePlus is the only one of the three care systems that contains ophthalmic demulcents (soothing agents). The FDA recognizes that demulcents alleviate ocular dryness and irritation. These agents are propylene glycol and hydroxypropyl methylcellulose (HPMC). Propylene glycol's role is to bind to water and to "maintain optimal lens lubricity". HPMC coats and conditions the surface of the lens with a time-released cushion of moisture. AMO's new MPS also contains taurine and "essential electrolytes" that may help protect corneal cells from osmotic stress.
These new MPSs join the ranks of Opti-Free Express Multi-Purpose Disinfecting Solution Lasting Comfort No Rub Formula (Alcon) and ReNu MultiPlus as exceptional soft lens care products. See Table 1 for a concise look at these new products and Table 2 for information regarding their recommended cleaning regimens.
Newly released rewetting agents have also taken strides to enhance contact lens moisture and comfort. blink Contacts Lubricating Eye Drops (AMO) and Aquify Comfort Lens Drops (CIBA Vision) both use sodium hyaluronate (HA) for moisture retention and ocular lubrication (see Table 3). HA is a natural lubricant that we can find throughout the body. According to both AMO and CIBA, HA has "viscoelastic properties" that are similar to natural tears. In the open eye, HA molecules randomly interlock and become tangled, thus providing a highly viscous surface. The result is increased tear retention time. Each time a patient blinks, his lids re-distribute a new layer of HA over the ocular surface. The concentration of HA in Aquify Comfort Lens Drops is 0.10% while blink Contacts' concentration is 0.15%.
To help with patient comfort, blink Contacts employs OcuPure as its preservative. OcuPure is a peroxide-free preservative that simply breaks down to water and sodium chloride when exposed to light. Aquify Comfort Lens Drops uses sodium perborate (0.028%) as its preservative. Both rewetting agents are no longer care system specific and are approved for use with soft and GP contact lenses.
Two other unique rewetting agents are Complete Blink-N-Clean Lens Drops (AMO) and Clerz Plus (Alcon). In addition to moisturizing the ocular surface, both agents claim to help eliminate lens surface protein and deposits. Table 4 offers more information on these two contact lens care products.
Blink-N-Clean uses HPMC as its lens surface lubricant, but unlike most other rewetting agents, it also contains tyloxapol and tromethamine. Tyloxapol works by removing lipids and debris while tromethamine "emulsifies and displaces protein buildup". The HPMC also helps to prevent further attachment of debris. Blink-N-Clean is approved for use with all types of soft contact lenses.
Offering similar benefits as Blink-N-Clean, Clerz Plus uses Tetronic 1304 to retain contact lens moisture and to prevent protein buildup, while RLM-100 (lauryl ether carboxylic acid) works to remove lens surface deposits. You can prescribe Clerz Plus for use with both soft and GP contact lenses.
Hydrogen Peroxide Care Systems
Hydrogen peroxide is still an important part of contact lens care. Many practitioners still rely on this option for soft contact lens wearers as well as for GP lens patients. One reason behind these products' staying power is their lack of preservatives. Another is the reduction of "dry eye" symptoms stemming from solution sensitivities.
Clear Care/AOSept Plus (CIBA Vision) Practitioners often prescribe AOSept for patients who deposit heavily on lenses and/or for those who have preservative sensitivities. The AOSept System includes Miraflow extra-strength daily cleaner for lenses with significant build up. While AOSept has been highly successful in contact lens care, many may consider Clear Care the newer, patient-friendlier version of AOSept. It's a one-bottle, no-rub, hydrogen peroxide-based solution. Clear Care may prove beneficial for noncompliant patients, as it's formulated with a built-in cleaner that decreases protein deposits without the need to rub the lenses.
UltraCare (AMO) UltraCare is a hydrogen peroxide-based disinfecting solution/neutralizer with an ophthalmic lubricant built in. This allows the neutralized solution to retain and seal in surface moisture, increasing patient comfort. It's helpful to counsel patients about the fact that the solution will turn pink upon instillation of the neutralizing tablet.
GP Lens Care Systems
There have been fewer changes in this lens care arena. The multi-bottle systems by Bausch & Lomb and Lobob Laboratories are still highly effective cleaning and disinfecting systems. However, two new systems, Boston Simplus (B&L) and Unique-pH (Alcon) aim to streamline the process by moving toward MPSs, much like in soft contact lens care.
Boston Simplus Multi-Action Solution As the newest product in the GP care armamentarium, the goal of Boston Simplus is to offer ultimate convenience and cleaning capabilities. It's a one-bottle daily lens care system that cleans, disinfects, conditions and removes protein. According to B&L, Boston Simplus's ability to remove protein is comparable to Boston Advance Comfort Formula System, which is a two-step system. Even more convenient is the discontinuation of the evening rub. The patient simply removes his lenses at night and soaks them. In the morning (before lens wear) the patient performs a brief rub-and-rinse step.
Unique-pH This one-step MPS contains the proprietary polymer system hydroxypropyl guar, which adjusts the solution's viscosity based on the individual's tear chemistry, or pH. Along with Tetronic 1304, this solution can enhance comfort by providing a layered cushion around the contact lenses. You may consider adding Opti-Free SupraClens Daily Protein Remover to the lens care regimens of patients who have heavy protein buildup.
Boston Original Formula System and Boston Advance Comfort Formula System These tried-and-true GP lens care systems originally by Polymer Technology Corp. and now by B&L consist of a cleaner and a conditioning solution. The Boston Advance Comfort Formula System enhances lens comfort because of the conditioning solution's ability to coat the lens. You can add weekly Boston One Step Liquid Enzymatic Cleaner for patients who have heavy lens surface protein or lipid build-up.
Optimum by Lobob Laboratories The Optimum line of contact lens products consists of The Optimum by Lobob Cleaning/Disinfecting/Storage (C/D/S) Solution and an "Extra Strength" Cleaner and Wetting and Rewetting Drop. It's made up of a combination of proprietary surfactants, each capable of disrupting the "electrostatic" attraction properties of surface debris. Prolonged exposure to the surfactants during the overnight soak allows for increased protein and lipid removal. Unlike other GP lens cleaners, the C/D/S Solution contains purified benzyl alcohol as the preservative. According to Lobob, this key difference makes Optimum 99.9 percent effective against Pseudomonas. You can use the "Extra Strength" Cleaner in conjunction with the C/D/S solution to remove heavy deposits of oils, lipids, salts and cosmetic residue.
In-office Cleaner & Disinfectant
Menicon Progent is a unique, in-office-only cleaning solution for GP lenses that has been available to US practitioners since 2003. This disinfecting system can effectively loosen and remove surface protein deposits after a short soak without manual rubbing. It works by mixing two ampules (sodium hypochlorite and potassium bromide) into a special lens case. A doctor or his staff soaks the lenses in the mixture for no more that 30 minutes and then re-cleans them with standard GP lens cleaner before the patient wears them. Take caution to not spill this solution, as sodium hypochlorite is similar to household bleach. Published data show that Menicon Progent is highly effective in killing bacteria, fungi and yeasts (see Table 5).
Better Care Systems, Better Compliance
It's clear that manufacturers of contact lens care systems are taking a new approach. Those that make soft contact lens solutions have put an emphasis on retaining moisture and on alleviating dryness symptoms, while those that make GP lens care systems aim to effectively and efficiently streamline the cleaning regimen. There's promise that these and future contact lens care systems will help increase patient compliance and decrease the number of contact lens dropouts.
Dr. Tran is a clinical instructor in the Cornea & Contact Lens Service at the Southern California College of Optometry. He is also in group practice in Costa Mesa, CA.
Dr. Myung is an assistant professor at the Southern California College of Optometry. She's also the coordinator for the Pediatric Contact Lens Service.
Contact Lens Spectrum, Issue: April 2005