These are lenses that can be worn overnight in bed without having to extract them. They provide the additional advantage of being able to wake up in the morning with no less than 20/20 vision. Extended wear lenses admit a greater quantity of oxygen to the eye, thus making them easier to wear even during sleep.
Most of the EW lenses on the market can be worn for up to seven days without interruption. However, not every potential user has the capacity to wear these lenses for this length of time safely and comfortably. Wearing contact lenses in bed does increase the possibility of contracting eye infections. An eye care professional must, in the final analysis, decide if it is advisable for a patient to wear EW lenses or whether more regularly scheduled lenses might be more suitable from case to case.
The majority of EW models are soft, disposable contact lenses that can be easily disposed of while following the prescribed schedule. Some EW lenses are as rigid as gas permeable ones and thus can be reused and worn for longer periods than the softer disposable ones. However, they still need to be removed and cleaned. Additionally, the user’s eyes will also require rest from the lenses.
A new model of soft EW lenses designed for thirty days of continuous wear has been developed; they are made of a highly permeable softer lens, which permits increased levels of oxygen to pass through the lens and reach the eye. Note that an eye care professional must make the decision as to whether this type of lens is suitable.