Section on Cornea and Contact Lenses
Information for Eyecare Practitioners
CONTINUOUS AND EXTENDED WEAR CONTACT LENSES
The vast majority of contact lenses are worn on a daily basis and lenses are removed at the end of
each day before sleeping. This modality does not, however, offer the ultimate convenience sought
after by many wearers. Lenses have to be inserted and removed each day and, unless they are daily
disposables, they require daily cleaning and disinfection procedures. The prospect of day and night
lens wear without the need for daily handling and maintenance has, therefore, been appealing to
contact lens wearers since their very inception. Day and night lens wear first became a reality more
than twenty five years ago but its popularity and success has been particularly turbulent over this
What is meant by "Extended Wear"?
Extended wear (EW) typically refers to wearing contact lenses, both during the day and while
sleeping for periods of up to six nights and seven days consecutively. The majority of soft lenses
worn on an EW basis are “disposable”, and are usually inserted once only and removed and
discarded after one week of wear.
What is meant by "Continuous Wear"?
Continuous wear (CW) refers to wearing contact lenses both during the day and while sleeping for
periods of up to thirty days and nights consecutively. Initially this modality was used primarily for
therapeutic cases1 but when CW with conventional hydrogel lenses started to be prescribed more
widely, the high incidence of reported complications resulted in the Food and Drug Administration
(FDA) rescinding approval for wearing periods of greater than seven days and six nights in 1989.
The CW modality has more recently regained popularity following the introduction of highly oxygen
permeable silicone hydrogel lens materials and the FDA approved the use of silicone hydrogel
contact lenses for CW and the term “continuous wear” has now become synonymous with the us