contact lens care and compliance
Revisiting GP Diagnostic Lens Care
BY MICHAEL A. WARD, MMSC, FAAO
In September 2006 I wrote a Contact Lens Care column titled, "Maintaining and Disinfecting GP Diagnostic Lenses." I've recently encountered questions on this topic, so in this column I present an updated version of my previous column on this subject.
GP diagnostic contact lens sets will last for years if you care for and store them properly. Some trial sets get regular use, while others are used only rarely. Regardless of the frequency of use, you must be concerned about how you store and care for these diagnostic lens sets to ensure cleanliness, parameter accuracy and safety.
Regularly Check Parameters
Unlike soft lenses, you can accurately verify GP lens parameters with standard office instrumentation. You can use a magnifying loupe to inspect lens surfaces and to verify optic zone and overall lens diameters. A lensometer can be used to check GP lens power (for high powers, front versus back vertex becomes important) and optical quality. A radiuscope can accurately measure the base curves and allow you to detect any warpage or surface deposits. However, one thing these instruments can't tell us is whether the lens surfaces are free from microbial contamination.
Periodically inspect all GP diagnostic lenses to ensure that each is in its correctly labeled container and that the parameters haven't altered over time. Replace any warped or out of spec lenses.
Diagnostic GP Lens Care
Diagnostic GP lenses are best stored dry for prolonged storage. GP lenses stored wet in conditioning solution require regular maintenance to ensure an aseptic state. No contact lens disinfecting solution is approved for lens storage for greater than 30 days. You must redisinfect lenses that you store in wet chemical storage/ disinfecting/conditioning solutions at least every 30 days. If you don't regularly maintain wetstored GP diagnostic lenses, evaporation and aging may alter the chemical composition of the storage solution, which may compromise its antimicrobial efficacy.
All diagnostic contact lenses must be cleaned and disinfected prior to their reuse. The Centers for Disease Control and Prevention (CDC) recommends using ophthalmic grade 3% hydrogen peroxide for disinfection of rigid diagnostic lenses. Specifically, "Contact lenses used in trial fittings should be disinfected after each fitting by using a hydrogen peroxide contact lens disinfecting system for 10 minutes," www.cdc.gov/mmwr/preview/mmwrhtml/00000602.htm. The two primary peroxide systems available in the United States are Clear Care (CIBA Vision) and Oxysept (Abbott Medical Optics).
Clean GP diagnostic lenses with an approved surfactant cleaner such as Boston Advance Cleaner (Bausch & Lomb), Optimum Extra Strength Cleaner (Lobob Laboratories) or MiraFlow Extra Strength Daily Cleaner (CIBA) after each use and rinse thoroughly.
Disinfect the lenses with an approved peroxide system (Clear Care or Oxysept) for a minimum of 10 minutes.
Store rigid diagnostic lenses dry for long-term storage.
Prior to reuse, clean the lenses with an approved cleaner, then rinse and wet them with an appropriate wetting or conditioning solution. This above outlined practice of GP diagnostic lens handling minimizes the risk of microbial contamination of diagnostic lenses and provides a clean and comfortable lens experience for patients. I've followed this practice for many years, and I believe it is becoming the standard for care and handling of GP diagnostic lenses. CLS
Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and Director, Emory Contact Lens Service.