Soft contact lenses require scrupulous care, and must be cleaned by a multi-step process each time they are removed.
Remove the debris. The lenses are removed and washed with a commercially prepared "daily" cleanser. Rubbing the cleanser into the lenses works up a lather that removes debris.
Rinse away the soap. The lenses are rinsed in a saline solution, one that was either purchased or homemade by mixing a salt tablet with distilled water.
Kill the germs. Then the lenses are disinfected, either in an electrical heating unit (heat disinfection) or by rinsing overnight in a commercially prepared chemical disinfectant (cold disinfection).
Wet the lens. The next morning, the lenses are usually rinsed before they are put back in the eyes, either with more of the saline solution or with a packaged "wetting solution."
The frequency of this routine depends on the type of contact lens. Daily-wear soft lenses should be cleaned and disinfected every day; extended-wear lenses need to be disinfected, and removed for an overnight break, at least every two weeks.
Infections can be introduced in the saline rinse step, government researchers say. People who mix their own saline at home are at greatest risk. If a homemade solution is used, these researchers advise, then it should always be followed by disinfection.
The prepared saline solution, which is often available in store brands as well as the more expensive name brands, may contain a preservative to which some individuals are allergic. Recently, manufacturers have developed preservative-free solutions "for sensitive eyes."
In addition to the regular cleaning regimen, soft lenses should be soaked every week or two in a special enzyme solution to remove protein deposits.