Should You Sleep in Your Contact Lenses?
As a contact lens wearer myself I know it is very easy to fall asleep forgetting to remove your contact lenses either accidentally or on purpose. You may have even slept in your lenses but do you know the risks?
While some manufacturers market contact lenses for overnight wear, there are increased risks. This mode of wear is known as extended wear. It should only be done under the proper care and guidance of an optician.
There are many benefits to wearing lenses overnight such as convenience of not having to put on & remove lenses, waking up with clear vision and no need for any disinfectant systems, saving time and money. It is important to weigh up the benefits vs the risk when considering this mode of contact lens wear.
So how does the eye work?
The cornea is the transparent window in front of the coloured part of the eye known as the iris. The light passes through the cornea, through the pupil & focused by the lens just like a camera.
The cornea needs to be transparent to allow light to pass through & give clear vision, just like the lens on a camera. Therefore the cornea does not contain any blood vessels & gets its oxygen supply from the air.
When a contact lens is worn this inhibits the supply of oxygen to the cornea.
When your eyes are closed at night this limits oxygen supply further. Without oxygen the cornea swells and becomes hazy. This leads to reduced vision & inflammation. If left long enough vessels start to grow into the cornea to supply oxygen, permanently threatening the transparency. Once these vessels enter the cornea they can not be removed. Imagine trying to take a photo with a dirty or damaged camera lens?
It is important that only lenses with a sleep licence are worn overnight.
These lenses are made from a special material called silicone hydrogel which allows sufficient oxygen supply to the cornea.
OK so you buy high oxygen lenses with a sleep licence, therefore it must be fine now, isn’t it?
“The biggest risk of extended wear is infection, which can lead to blindness”*
This is caused by parasites, foreign bodies or a build up of toxins becoming trapped under the lens leading to inflammation or ulceration of the front of the eye.
Cooper Vision report there to be up to 15 times greater risk of ulcerative keratitis (a sight threatening condition) if you sleep in your contact lenses, even if they have a sleep licence. If you are a smoker your risk is even higher.
If a lens is removed each night the risk of infection is reduced significantly
The more nights in a row the lens is not removed the more risk of a build up of toxins leading to sight threatening complications.
Even Cooper vision who manufacture and market lenses for extended wear state on their website
“When possible remove even extended wear lenses before sleeping.”
So if you regularly sleep in your lenses do you shower & swim in them too?
Water has to be the biggest NO! NO! of contact lens wear.
Bacteria and other parasites live in moisture and your contact lens will act like a sponge & soak them up holding them against your eye.
Some infections caused by swimming or showering in contact lenses can cause infections which can lead to permanent loss of sight.
The British Contact Lens Association advise “close yours eyes tightly when showering” Would you rely on this as protection when risking blindness?
I know you are thinking why give a contact lens a sleep licence at all?
There are some circumstances where it may be desirable to sleep in your lenses such as camping, emergency services on call or armed forces on patrol.
In these cases it can be argued it is a reasonable risk, particularly if you have a high prescription or hygiene areas are not available for safe contact lens removal & disinfection.
However this should always done under strict supervision of a contact lens practitioner.
If you are thinking of trying extended wear lenses consider is it necessary and worth the increased risk?
Can I wash & shower safely? Do I have any health conditions which can increase my risk such as dry eye, arteritis or diabetes? Do I do any high risk activities such as water sports? Can I commit to all the extra appointments to see my optician?
Would the safer option of daily disposables, now available is a wide range of prescriptions, be a better choice?
Contact lens manufacturers recommend a new extended wear patient is seen up to 8 times in the first year. It is then advisable that you see your optician every 3 to 6 months ongoing. Daily wear contact lens wearers usually only need an annual appointment once fitted.
If you would like any more information regarding this or any other eye related subject please contact us for information.