What are the long term effects of sleeping in 30 day contact lenses that arent meant to be slept in?
Bad idea. Never sleep in your contact whether they say you can or not. Sleeping in contacts can lead to serious cornea infections.
Bad. Dry eyes, infection, corneal abrasion, corneal scarring. Contacts are so comfortable theses days, we often take them for granted until they start to feel bad. Follow the manufacturers guidelines as closely as you can to minimize any risk to your eyes. The contacts are replaceable and relatively cheap. You only get one pair of eyes, take care of them.