Extended Wear Contacts
Extended Wear Contacts
Extended wear contacts are those that can be slept in for anywhere from 1 to 30 nights. Most of the extended
wear contacts available are soft ones, but some Rigid Gas Permeable (RGP) can also be worn as extended wear contacts too.
(But not hard contacts, which let in very little oxygen.)
Extended wear contacts are contrasted to daily ones - which have to be taken at the end of each day. It
was in the 1980's that the first contacts
that could be worn overnight became available.
Although the FDA approved of contacts that could be worn for 30 days in 1981, it was changed sometime later.
It had been found that people who wore them that long might have a greater chance of getting eye infections.
So the FDA then reduced the wearing period to only seven days.
The material extended wear contacts are made from is newer, like silicone hydrogels. This These newer materials
let more oxygen through than soft contacts do - usually 5 or 6 times more! Because they let in more oxygen
they can be worn for a longer period of time, since eyes are healthier when more oxygen is available.
While many can only be worn for 6 nights at a time, some can be worn for up to 30 nights. Sometimes these
contacts are actually referred to as continuous wear (CW) contacts since they can be worn for so long.
Typically extended wear contacts are thrown after they are worn for the maximum time specified. So many extended
wear contacts are also a type of diposable contact.
Extended wear contacts that are also soft contacts, are also soft and pliable and feel more comfortable to wear.
Prescriptions for them work the same also - a number of different measurements are taken such as the power,
base curve and diameter.
Why Wear Extended Wear Contacts?
Some people may wonder why someone would want to wear extended wear contacts. The following
are my personal opinions on why someone, like myself, wants to wear them. With contacts that you can leave in
all the time, all day and through-out the night - feel almost like you don't have bad eyes anymore!
That's a great feeling! Especially when its time to get up in the middle of the night to use the bathroom.
It can really be a pain in the behind to have to reach around in the dark trying to find your glasses just so you can
find the bathroom! Taking a shower without being able to see what you are doing either can be a pain. Drop the
soap, and then you can't find it! Or if you lose an earring or something in the shower - like happened to me recently
when I wasn't wearing my contacts, it ended up going down the drain - if my contacts had been in I could have
seen it on the bottom of the shower and saved it.
Another point someone brought up elsewhere is for people with kids or babies and they have to get up in the middle of
the night to take care of them - I'm sure many women could appreciate how it would be nice to be able to see what
you are doing in that situation!
Common Brands of Extended Wear Contacts
O2 Optix: O2 Optix (which is what I wear now) are soft contacts made by CIBA Vision Corp. They have a water content of
33% and are made of 67% polymer (lotrafilcon B). Their oxygen transmission is 138 Dk/t, which is the highest
of the two week disposable contacts. They can be worn for 6 nights, taken out and cleaned one night then
worn for another 6 nights, then thrown away. They come in powers of -.25 to -6.00, base curve of 8.6 and diameter 14.2.
Night & Day: Night and Day contacts are also made by CIBA Vision Corp. and are soft lenses.
They are one of the few brands that can be worn for 30 nights! They let in 175 Dk/t oxygen - 6 times more oxygen
than most contacts. They are 24% water and made from 76% polymer - Lotrafilcon A, a fluoro-silicone material.
Powers available are .25 to 6.00 and -.25 to -10.00, base curves are 8.40 and 8.60, diameter, 13.8.
PureVision: PureVision are made by Bausch & Lomb and are also soft contacts that can be worn for 30 nights.
They are 36% water, 64% polymer (balafilcon A). Powers available are .25 to 6.00 and -.25 to -12.00, base curve
8.6 and diameter 14.00.
Other articles in this series are:
Contacts - An Introduction Part I: Eyes and Vision,
Contacts - An Introduction Part II: Contact Types and History,
Soft Contacts - Daily Wear and Disposable,
Rigid gas permeable (RGP) Contacts,
Daily Wear Contacts and
Some related web sites are
CONVENIENCE IS KEY IN CONTACT LENS CHOICE and
Contact Lenses for 30-Day and Seven-Day Wear.