The lightweight, unobtrusive nature of contact lenses has made them a popular choice for vision correction. If you've ever had a pair of eyeglasses fly off during a gym workout, or had them fog up on a cold day, then you can appreciate the freedom and convenience that contacts afford. It's even possible to forget that they're there sometimes, and it's not uncommon for wearers to end up falling asleep with their contacts still in! But is sleeping in contacts really a wise thing to do, especially on a regular basis?
Contacts and Corneal Health
It turns out that leaving your contact lenses in overnight can potentially lead to some serious complications, due in large part to the close and constant contact that the lens makes with the cornea (the clear, outermost layer of your eye). The cells that comprise the corneal tissue require oxygen for proper functioning, and the cornea also needs a flow of fresh tears to lubricate the eye and wash away bacteria and debris. Any contact lens impedes the cornea's access to oxygen to some extent; and when your eye is closed, that contact lens also acts as a physical barrier between your eyelid and cornea, impeding access of both oxygen and tears to the corneal surface. During a short period like a nap, this may cause some irritation and the feeling that your contact lenses have dried up and "stuck" to your eyeballs, making removal difficult or painful. You also risk corneal abrasion when removing your contact lenses from you eye when it is dry.
Complications from Sleeping in Contacts
If you frequently leave your lenses in overnight, however, you may experience even greater complications, because your eyes are never given the opportunity to "breathe" and get a proper cleansing from the tears. The constant adhesion of the lens to the cornea can lead to hypoxia (oxygen deprivation), inflammation, abnormal blood vessel growth into the cornea, and/or microscopic abrasions in the corneal surface. Germs may begin to accumulate, and the cornea may in turn become infected. The most common infection related to extended contact lens use is keratitis, which can cause blurriness, pain, light sensitivity, and erosion of the cornea. Corneal scarring can eventually impair vision to the point of needing a corneal transplant, which is a serious situation indeed.
What about Extended Wear Contacts?
There are several types of contact lenses, including "daily wear" (which need to be cleaned after every use and removed before sleeping) and "disposable" (used once then thrown away). There is also a third type, called "extended wear" contacts, which are made from a special silicone hydrogel that allows more oxygen to pass through the lens. Extended wear contacts can be worn continuously for a prescribed period before being discarded, and are thus a popular choice with those intent on sleeping in contacts, for convenience or other reasons.
But the problem is that continuous wear can still increase the risk of eye infections. One of several studies has shown that people who slept in extended wear contact lenses were three times as likely to develop severe keratitis as soft lens wearers who didn't sleep in their lenses. As such, many eye care professionals still caution strongly against sleeping in extended wear lenses and insist that they be removed at least once a week for disinfecting and cleaning, and to give the corneas a break from being constantly covered.
So try getting out of the habit of sleeping in contacts if it's something you've been doing regularly - your eyes will welcome the rest, and you can sleep easier knowing you're not compromising your health!
For any questions or comments, please contact Woodhams Eye Clinic.
Image source: Flickr
