When you buy contacts online from contact lens websites like Lens.com, one of the first things to consider is the type of lens. This will tell you how long you can wear them for and what to expect if you happen to go over the recommended wear schedule. The first thing you should look for is whether your contacts are a daily wear or extended wear lens. If you have been prescribed daily wear lenses, then your contacts should be removed and cleaned each night. Extended wear lenses, however, can be kept in overnight.
The main concern with prolonging the wear of your contact lens is that by doing so you will be preventing enough oxygen from reaching your eye. Sleeping with lenses that are not meant to be slept in will create a barrier between your cornea and eyelid. This tight fitting barrier blocks any oxygen or natural lubrication from your tears from reaching your eye.
Pay Attention to Materials
Another reason to avoid overnight or extended wear of daily contact lenses is due to the material that they are made of, which tends to be thicker. The thinner material that most extended wear lenses consist of allows for more breathability, which in turn translates to more oxygen reaching your eye. However, even with this type of material if your eye is feeling any strain or discomfort then remove your contact lenses and try wearing them for shorter periods. The timeframe in which your lenses are able to be worn is just a recommendation and does not need to be strictly followed.
Risk of Infection
Wearing contact lenses for long periods of time, and especially overnight, can increase your risk for infection, which is why most eye care professionals encourage lens wearers to remove and clean their contacts each night even if they have been prescribed with extended wear contact lenses. The possibility for infection again ties back to the amount of oxygen that is able to reach your eye, so sleeping with your contacts in gives bacteria the chance to stick to your lenses and the closed space created by your eyelids provides the right environment for infection to grow. The types of infection that can occur range in severity from something as minor as pink eye to something more serious like bacterial keratitis. If left untreated the more severe infections can result in loss of vision.
So while you may have been recommended extended wear lenses by your eye doctor, it is still good practice to remove them frequently, even nightly, for a thorough cleaning with contact solution. The chance for infection is a big risk to take especially when it can have such severe consequences. It is always better to take the more cautious route when it comes to the health of your eyes.