Contact Lens Care & Compliance
A New Preserved Saline Enters the Market
BY MICHAEL A. WARD, MMSC, FAAO
Alcon recently launched Clear Care Rinse & Go saline, which is intended for rinsing and temporary storage of soft contact lenses after cleaning and disinfection with hydrogen peroxide lens care products. Clear Care Rinse & Go is a preserved, isotonic, buffered, aqueous saline solution containing polyquaternium-1 (Polyquad, PQ-1) 0.001%, citrate, and edetate disodium (EDTA) 0.05%. The package insert states that it is indicated for rinsing and storage of soft contact lenses for up to 30 days following disinfection.
What’s in a Saline?
Saline solutions do not disinfect contact lenses. They are indicated for lens rinsing and/or temporary storage after lens disinfection. The preservatives in salines only preserve the solution; they are not sufficient to disinfect lenses.
Saline is simply a mixture of salt and water. Specifically, it is a salt (usually an ionic solid) disassociated in water, yielding a neutral charge. Saline solutions can be isotonic, hypertonic, or hypotonic. Contact lens rinsing and storage products are isotonic, which prevents swelling or shrinkage of soft lenses. Normal saline (NS) solutions are typically made of sodium (metal cation) and chloride (anion) in a 0.9% weight/volume NaCl solution in water. With a pressure of approximately 310 mOsm, they are isos-motic with body fluids and the ocular surface (Ward, 2013).
NS’s biocompatibility with the ocular surface makes it the perfect solution for rinsing contact lenses prior to lens application. Saline solutions for contact lens use may be preserved or nonpreserved, aerosol, multi-dose, or unit-dose.
Choosing a Saline
Preserved salines offer the convenience of multi-use containers and are less expensive compared to unit-dose salines. However, preserved salines are associated with a greater risk of ocular surface chemical sensitivity reactions in some individuals (Paimela et al, 2012; Freeman and Kahook, 2009). Current brand and generic preserved salines use a biguanide and EDTA. In fact, preserved generic salines that I researched for this article found at several retailers all have the same generic composition as one branded saline solution that I examined: “sterile, isotonic, buffered solution that contains boric acid, sodium borate, potassium chloride, sodium chloride, preserved with polyaminopropyl biguanide (0.00003%) and edetate disodium (0.025%),” (various URLs available at www.clspectrum.com/references).
Clear Care Rinse & Go contains the same concentration of the detergent-type quaternary ammonium compound PQ-1 that is in Alcon’s Opti-Free multipurpose solution line.
Multi-use, preservative-free salines eliminate the risks of preservative sensitivities, but are more prone to microbial contamination during use. Unit-dose saline offers a safe, preservative-free solution for rinsing, but is the most expensive. Advise patients to discard opened vials after use regardless of any remaining solution.
Preserved salines in multi-use bottles are good for rinsing cleaners or disinfectants from lens surfaces and for short-term lens storage following disinfection. Proper lens storage case care must be observed. Aerosol salines remain sterile until sprayed from the pressurized can and are a good choice for rinsing, but not for scleral lens use because the nitrogen gas propellant may form bubbles under the lens as the gas escapes solution. Unit-dose, nonpreserved saline is the best choice for scleral lens use. Saline solution should not be used for prolonged lens storage. CLS
For references, please visit www.clspectrum.com/references and click on document #249.
Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and Director, Emory Contact Lens Service. You can reach him at email@example.com.