Wearing extended wear contact lenses overnight is almost like natural sight since you awake to clear vision. And since you don't have to take them out every night, you cut down on the cleaning chores. Extended wear contact lenses can also let you go on short trips without having to take any cleaning solutions.

Early contact lenses were made of a plastic that didn't allow oxygen or other gases to pass through it. This meant that wearing contacts kept your cornea from getting an adequate oxygen supply. This led to eye irritation and the lenses couldn't be worn for long periods. But with the use of a gas permeable plastic, extended wear contact lenses became possible.

When you're sleeping, your eyelids are closed, so there's a natural reduction in oxygen getting to your cornea. And this is why it's especially important for extended wear contact lenses to allow as much oxygen to pass through as possible.

Twenty years ago some contact lenses were sold as continuously wearable for up to a month. But the importance of getting sufficient oxygen to the cornea wasn't known at the time. And people who were using these, supposedly extended wear contact lenses, developed eye problems, so the Food and Drug Administration stop their use. After that, lenses were to be worn continuously for no more than a week.

CIBA Vision broke the one week limitation for extended wear contact lenses with their Night & Day contacts. The lens material passes through up to six times more oxygen than other soft lenses. And the biocompatible surface lessens the buildup of dirt and bacteria. These two factor mean less eye irritation and more importantly, healthier eyes.

There are a few things to keep in mind when using extended wear contact lenses. Because they're in your eyes longer than daily wear contacts, it's especially important you clean them well when you remove them. And after wearing the lenses for an extended period, it's a good idea to wear them only daily for a while to help refresh your eyes. And of course, if you develop red or irritated eyes, you should see your eyecare professional.