[Editor’s note: This article was originally hosted on MyFamilyDoctorMag.com, our sister site.
It’s now featured here as part of our new general-health section.]

by Louise A. Sclafani, O.D., F.A.A.O.

Q. My ophthalmologist said I could wear my brand of disposable contacts for two weeks. What happens if I wear them longer? Also, why can you sleep in some disposables and not in others?

A. Putting a piece of plastic on your eyeballs requires a certain amount of tender loving care. But these days, not all contacts are made of the same kind of plastic. What they are made of determines the kind of care you have to give.

Determining Factors
Why you can wear some contacts longer than others

Two main factors that contribute to how long you can wear your lenses, both daily and over the long term, are how well they breathe and how much they like to collect stuff.

Books adYour eyes need oxygen to stay healthy. Contact lenses are made of different kinds of materials that allow differing amounts of oxygen to get through. This makes certain types of lenses acceptable for sleeping.

You may wonder why it matters how much oxygen your eyes get if they’re closed anyway. Actually, the outermost portion of the cornea (the clear dome covering the colored part and pupil) gets much of its oxygen in dissolved form from the tears! Contact lenses can block this process.

Some materials are also more prone to deposits, such as proteins and lipids, which are normal components of our tears. If they build up on the lens, they can cause problems, including infection. (Besides, nobody wants to look through a dirty window.)

Various products are available to clean and disinfect lenses; however, if you don’t use them properly, or if you wear the lenses longer than the prescribed amount of time, you put yourself at risk for complications such as corneal ulcers and inflammation.

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Hidden Changes
Why to listen to the rules—even if you think you’re OK

People who overwear their contacts are often not aware of changes that may be occurring on their eyes because you can’t see them without a microscope. They may only finally visit their eye-care professional after a problem has advanced to the point of causing severe pain or vision loss.

It’s important to have your lenses evaluated routinely to be sure the wearing schedule is working well for your eyes and that your corneas remain healthy. At these visits, your provider can also offer new materials or solutions as they’re developed.

, is an associate professor of ophthalmology at The University of Chicago, chair-elect of the American Optometric Association Contact Lens and Cornea Section and a team eye doctor for the Chicago Blackhawks hockey team.

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