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Contact lens

A soft contact lens.
A contact lens is a corrective or cosmetic lens placed on the cornea of the eye atop the iris.

Contact lenses were invented in 1887 by the German physiologist Adolf Eugen Fick (1829-1901).

Made of various kinds of plastic, contact lenses come in a number of varieties, including hard and soft (although soft is by far more common now), and disposable and extended-wear. The specific dioptre needed to treat the patient's condition can be prescribed by an optometrist and provided by an oculist.

Tinted contacts, which may or may not be prescription but are tinted to change the colour of the iris, are used for cosmetic reasons.

Toric lenses

People with myopia or astigmatism who have been told they are not suitable for regular contact lenses may be able to use Toric lenses. Toric lenses are made from the same materials as regular contact lenses but have a couple of extra characteristics:

Cleaning & Disinfecting Products

Contact lenses need regular cleaning and disinfecting to retain the clear vision and prevent infections. There are a number of products that can be used to perform these important tasks:

Some products may contain preservatives such as
thimerosal. However, about 10% of contact lens wearers had problems with these products so many brands no longer use it. Such thimerosal-free products are sometimes labelled "for sensitive eyes". Products that do not contain any preservatives usually have expiration dates. For example, non-aerosol preservative-free saline solution typically only last two weeks once opened.