Saline Solutions for Contact Lenses
Types of Saline Solutions
Contact lens saline solutions can be divided into three types:
- Commercial solutions with preservatives.
- Commercial solutions without preservatives.
Contact lens wearers should follow one simple rule with regard to saline:
Always use the commercial saline your eye care practitioner recommends. Never use saline prepared from salt tablets, i.e., home-made solutions.
Functions of Saline Solution
Saline solution acts as a rinsing agent to prepare the contact lens for wear. Rinsing with saline solution helps:
- Remove debris from the surface of the lens.
- Remove cleaning solutions, which can be irritating to the eye, from the surface of the lens.
- Maintain the water balance of soft contact lenses.
A main function of saline is to moisten contact lenses. Never use saliva to moisten a contact lens; never put a contact lens in your mouth. (Saliva is a source of bacteria that potentially can cause ocular infection.)
Some commercial saline solutions use preservatives to slow the growth of bacteria after the container is opened. Be sure to follow the manufacturer's guidelines on how long these preserved saline solutions can be safely used or ask your eye care practitioner. Unfortunately, some people are sensitive to the preservatives used in these solutions and can develop eye irritation following the use of preserved solutions. For these people, there are preservative-free, sterile saline solutions.
Preservative-free commercial saline solutions solve the problem of sensitivity; but, after opening, preservative-free solutions can become contaminated more quickly than preserved solutions. Preservative-free solutions come in unit doses, spray cans, and standard bottles. Unit-dose (single-use) saline provides the greatest margin of safety but is also the most expensive. The unit-dose vials must be discarded after one use, even if solution remains in the vial. Spray cans are economical and provide multiple usage. Care should be taken not to contaminate the tip by touching it. Larger bottles of preservative-free solution tend to become contaminated and generally should be replaced every two weeks or as recommended by the manufacturer. An alternative to preservative-free commercial saline solutions for patients who are sensitive to preservatives are the saline solutions for sensitive eyes. These are preserved and thus more convenient to use, but are specially formulated with preservatives and less likely to cause irritation in the susceptible patient.
Avoid Using Home-made Saline
Neither home-made saline nor distilled water should ever be used with contact lenses. Enzyme tablets should be dissolved in commercial sterile contact lens saline solution. Since there are inexpensive alternatives, there is no reason to use distilled water, home-made saline, or non-contact lens commercial saline.
Replace Solutions Regularly
Regular replacement of saline solutions is very important. When lenses are taken out of the case, the solution in the case should be discarded immediately. The case should be rinsed and allowed to air dry. Fresh solution should be added when the lenses are put back in the case. Also be sure to replace the contact lens case itself periodically as recommended by your practitioner. Expiration dates on saline bottles tell you only how long the bottle can remain on the shelf before opening. Follow the manufacturer's guidelines or ask your practitioner how long preserved and non-preserved saline solutions can be used after opening. Dispose of unused opened solution bottles as recommended by your practitioner. Since people who wear lenses overnight use solutions less frequently than people who take out their lenses every day, they should purchase solutions in small bottles to avoid waste. Solutions sitting in the lens case do not remain disinfected for long periods. Therefore, if your lenses have been stored for longer than overnight, be sure to disinfect before wearing them again. Using only fresh, sterile solutions will help make your contact lens wear safe and enjoyable.
The above information is taken from the CLAO Patient Information Pamphlet titled CONTACT LENS SALINE SOLUTIONS. Pamphlet Advisor was Elisabeth J. Cohen, MD. Copyright 1997-2004, Contact Lens Association of Ophthalmologists, Inc.