Contact lenses are thin, curved pieces of plastic that fit directly onto the surface of the eye to correct vision or provide additional visual enhancement. They can be used as an alternative to glasses for people who have problems with their eyesight and prefer not to wear spectacles. Contact lenses work by altering the way light enters the eye, which helps to improve vision in a similar manner to wearing glasses. There are different types of contact lenses available, including disposable soft lenses, daily-wear soft lenses, extended-wear soft lenses, gas permeable (GP) lenses and toric lenses for people with astigmatism. The type of contact lens recommended will depend on the individual's specific vision needs and eye health.