Silicone hydrogel contact lenses are a new generation of contact lenses that are able to transmit 6 to 7 times more oxygen to your eye than traditional hydrogel lenses. This is important because your eyes need oxygen for them to stay healthy and for you to have good quality eyesight. When insufficient oxygen reaches they eye, it can lead to eyestrain, swelling, and even scar tissue formation. Because silicone hydrogel lenses allow more oxygen through to the eye, they are much better for the health of your eyes and can also help avoid eyestrain which may be caused by wearing the older hydrogel contact lenses.

Traditional hydrogel lenses are composed of hydrogel polymers, which are soft, water containing plastics in which the plastic is not oxygen permeable but the water is able to carry oxygen through the lens to the eye. However the amount of oxygen that water can carry is limited and the amount of water the lens can contain is also limited. Therefore these lenses often let through a less than ideal amount of oxygen to the eye. The reason that the lenses cannot increase their water content too much is because the greater the amount of water in the lens, the greater the lens’ tendency to dehydrate as it quickly loses the water during lens wear.

Silicone hydrogel lenses are able to let more oxygen through because they are made of hydrogel polymers and silicone. Silicone is oxygen permeable thus, in these lenses, both the water and silicone transmit oxygen to the eye. This allows these lenses to have a lower water content and still be more oxygen permeable than the regular hydrogel lenses.

For those of you that wear contact lenses this means that your lenses will be less dehydrated and thus much more comfortable at the end of the day.

Because these lenses allow such a high amount of oxygen through to the eye, extended wear is also an option for some patients. Extended wear means being able to wear the lenses all day and night for a period of time that your eye care practitioner has approved. Some silicone hydrogel lenses, like CIBA Vision’s Night & Day, are often approved for 30 day extended wear for qualified patients. Basically, this means that once the lenses are in, you don’t have to remove them until the end of the month, then you switch them for a new pair. Because of the convenience of these lenses, they are a highly regarded alternative for laser vision correction and are often chosen by patients who can’t afford — or don’t want the risk of — LASIK surgery as well as by those patients who aren’t good LASIK candidates.

Extended wear is not for everyone though. Some people may find that their lenses become too dry or uncomfortable if they wear them overnight. Also, patients who have had problems with contacts previously may not be good candidates for extended wear. Even for patients that are good candidates there is an increased risk of eye infections with overnight contact lens wear. This risk can be minimized by following your eye care practitioner’s instructions for cleaning and disinfecting as well as following the recommended lens replacement schedule.

However, even if you don’t wear them for extended wear, you will most likely find the improved comfort, clarity and eye health afforded by the silicone hydrogel lenses good reasons to switch away from traditional hydrogel lenses. To discover if silicone hydrogel lenses would be a good fit for you or to get more information about these lenses, talk to your eye care practitioner.