Contact lenses are mainly used for corrective (correction of refractive errors of the eye like myopia, astigmatism, hypermetropia and presbyopia) purpose. Generally contact lenses are used for correction of myopia or short sightedness, hypermetropia or long sightedness, astigmatism (a condition where light rays are not focused on retina), and presbyopia (inability to adjust the eyes to focus on far and near objects quickly). Many individuals, especially younger generation do not want to use glasses for correcting refractive errors of the eye and prefer to use contact lens instead.
Contact lenses can be soft lens or hard lens. There are several advantages and disadvantages of using either type of contact lens (hard as well as soft lens). The advantages of using soft contact lens are the comfort of use and lesser chances of injury to the eye due to softness of the lens. The advantages of hard contact lenses are the cheaper price and longer lasting qualities of hard lens.
One of the major disadvantages of using contact lens over glasses is the chance of infection and injury to the eyes, especially if not used with proper caution with aseptic precaution and care. To overcome this common problem of contact lens, nowadays disposable contact lenses are available and very popular. Disposable soft lenses as well as disposable hard lenses is available. The disposable contact lens can reduce the incidence of infection drastically and use of disposable soft lens can cut down the incidence of injury to the eye due to use of contact lens.
Soft contact lenses are also used for therapeutic purpose e.g. use of soft contact lens to protect injured eye or cornea from constant rubbing of the cornea due to blinking, which allow the injured cornea to heal properly and faster. Contact lenses are also developed to deliver drugs in certain conditions.