The expiration date on contact lens solution is the date after which the manufacturer cannot guarantee that the solution will remain stable. After that date, chemicals start to precipitate out of the solution, meaning that the active ingredients may not be effective. The solution itself does not become poisonous, stresses Barbra Kelley of Bausch & Lomb, but its decreased potency puts you at risk for eye irritation and infection. More specifically, says Anne Sumers of the American Academy of Ophthalmology, fungal or bacterial ulcers can develop, and protein buildup on the lenses can cause irritation or an allergic reaction, which could make contact lens use difficult or uncomfortable for years.
Developing after decades
A roll of film is generally good long after the expiration date, says Paul C. Allen of Eastman Kodak Co.—as long as you don't store it in a hot car or damp basement. Heat and humidity, however, cause changes to the chemical emulsion on the film that can result in color shifts, such as green-colored skin, and in decreased sharpness. But film is pretty tough stuff, Allen says. As an example, he notes the photo on the back of Kodak's annual report: A customer had just developed a roll of film that had been sitting around for 40 years. "It came out fine,” Allen says.
Don't mess with medicine
The expiration date on cold medication indicates when the medication loses 10 percent of its labeled potency—meaning it is only 90 percent as effective in unclogging stuffy noses and relieving pain. Because expired medications don't usually look different, says pharmacist Mary Lynn Moody of the University of Illinois-Chicago, taking them can lead to a false sense of security. Her advice: Don't.
After expiration date, contact lens solution______.
A．will remain stable
B．will become poisonous
C．will not be effective
D．will cause eye irritation
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