There is considerable debate on this issue among eye-care professionals depending on how conservative or research oriented any particular professional is. But the general thought is that sleeping in any contact is a possibly damaging action. There are some contacts that are specifically designed to be worn constantly regardless of your conscious state. Again, it depends on the individual doctor as to their recommendation. Some think constant wear contacts are very dangerous, and some recommend them to everyone. There are few reasons most doctors discourage sleeping in contacts. Your eye needs oxygen to stay healthy. Contacts vary in how much they allow your eye to "breathe". This is why some contacts are made for constant wear; they tend to be more gas-permeable. The amount of oxygen that gets to your eye is decreased slightly when you wear any type of contacts, and even more so when you sleep in contacts. This can irritate your eyes, increase the amount of visible veins in your eye, and some people theorize that it can cause other lasting eye health deterioration. Another reason is the possibility of infection. Bacteria or foreign objects (dust, pollen, etc...) can get trapped in between your contact and your eye causing infections and other serious eye health problems. This is less related to sleeping in contacts and more a concern if you wear contacts for extended periods of time (which necessitates sleeping in them, of course.) As with any health issue, every person is different, so always follow the advice of your doctor. Your eye care professional will know your specific eye issues and whether or not sleeping in contacts is ultimately damaging to you personally. .

There are contacts available that have been tested and given the OK by the FDA, to be worn for 30 days without removing. Their studies show no increased risk of harm to the eyes with this wearing schedule. All these different plastics that they've invented allow more oxygen to pass through the contacts and reach the surface of the cornea. The cornea has no vascular supply and must absorb it's oxygen from the atmosphere. Most people who sleep in their contacts, take them out once a week and clean them. They are more comfortable when clean and you can see more clearly through a clean contact. If you are considering sleeping regularly in your contacts go with a brand that has a high dk/t rating. Some of these are Purevision, Acuvue Oasys, and Night & Day. I'm not employed by any of the manufacturers of these lenses.

well my optometrist told me not to sleep in them...so I'm not about to challenge that. (i wear 2-week disposable ones). He said that wearing them overnight would reduce oxygen to my eyes, not allow my eyes a break from the contacts, and also allow bacteria to grow between the contact and my eye. I have though, fallen asleep by mistake wearing my contacts. I didn't like the feeling of wearing them nonstop for so long- and my eyes felt dry and sore. Simply based on how uncomfortable I felt, I think it's not a good idea to wear them to sleep. But there are contacts designed for 24/7 wear, so if you would prefer that, ask your optometrist.