Contact lenses work in a similar way to glasses. Both forms of vision correction alter the direction of light rays to correctly focus light on the retina. Contact lenses correct your vision in a few ways. They can correct myopia – or short-sightedness – by using a concave ‘minus powered’ lens. Similarly, they can correct hyperopia – or long-sightedness – with a convex ‘plus powered’ lens. When either type of lens is placed in front of the eye, it moves the image back to the retina and clarifies it, which gives the wearer clear vision.

There are two other commonly-occurring conditions - astigmatism and presbyopia. Contact lenses can correct astigmatism by using different correctional powers across the meridians of the lens. And for people with presbyopia, multifocal contact lenses are used to correct vision across many different lens powers, in order to see objects at all distances.