How safe are contact lenses?

One of the dangers associated with wearing contact lenses is a reduction in the amount of oxygen reaching the front surface of your eye. As your lenses reach across the cornea (the outer part of the eye) if worn for too long they can restrict the amount of oxygen flowing to the eye. This can lead to the appearance of red veins growing in the cornea, as the eye tries to access oxygen, and this can lead to warping of the cornea and impaired vision if the eye continues to be starved of oxygen.

It is easy to avoid restricting the oxygen supply to your eyes by following simple advice.

• Remember not to wear contact lenses for too long at a time, it's best to keep a pair of glasses handy so you can give your eyes a break when needed. For most lenses, that period is around 10 hours, although specialist lenses can be purchased which last for longer.
• You might also consider trying silicone hydrogel lenses. These lenses allow around 5 times as much oxygen to reach the cornea as normal lenses, decreasing the risk of oxygen deprivation.