What are extended wear lenses?
Extended wear lenses are usually monthly lenses that are designed to be worn for between a week and a month without needing to be taken out. This means that you can fall asleep in them and wake up with clear vision.
Sometimes an optician will recommend monthly lenses that aren't specifically designed for extended wear for this kind of wearing pattern. This will usually depend on how breathable the lenses are, as well as how well they retain moisture and if your eyes have plenty of natural tears to keep them hydrated and comfortable. Most extended wear contact lenses are made from silicone hydrogel for these reasons.
Daily lenses aren't suitable for extended wear as they are designed to be disposed of each day and so won't comfortable or safe to wear for more than one day. There are some 2-weekly lenses, such as Acuvue Oasys, which can be suggested as suitable for extended wear.