Prolonged wear of the contact lenses means that they can be weared during night and all the way to the end of the time recommended by ophthalmologist. Some of those lenses are thrown away while replacing them. Others are cleaned, desinfected and reused before they are replaced. You should always adhere to the instructions given by your doctor. Did you know that exchanging contact lenses with other persons is dangerous and presents great danger for safety and health of your eyes? Contact lenses are adjusted to individual eyes and should never be exchanged with anybody else.