A corrective, cosmetic or therapeutic lens placed in the cornea of the eye is called a contact lens. It is a thin, transparent, plastic disc. Contact lens serves the purpose of conventional glasses but it is lightweight and almost invisible. In fact, some commercial lenses are tinted, generally to light blue color, to make them more visible while immersed in solution.

Nearly two percent of the people through out the world use contact lenses. There are many reasons for people opting for contact lenses. Majority of the people choose contact lenses for enhancing their appearance and making it more attractive. Also, contact lenses are less prone to wet weather, provide a wider vision field, do not steam up and are more suited for many sporting activities. In addition to this, certain ophthalmologic conditions can be accurately corrected with contact lenses.

Contact lenses are in varied designs.

Spherical contact lenses are typically round in design and have the ability to correct myopia (near sightedness) or hyperopia (far sightedness)

Bifocal: These lenses correct presbyopia- an age related defect of the eye and have different near and far vision zones.

Orthokeratology lenses reshape the cornea during sleep thus avoiding daytime wear of the lens.

Toric contact lenses correct myopia, hyperopia and astigmation.

Many of these lenses come in colors that enhance the natural color of the eye. To choose the correct contact lenses, in the first place, it is necessary to find out the purpose for which they are worn. Secondly, the lenses must be of correct diameter and curvature to fit the eye exactly and finally if the eyes tend to be dry, appropriate lenses should be chosen. There are many types of contact lenses like hard contact lenses, soft contact lenses, and rigid gas permeable and disposables and it is essential to find out the kind that suits a person. "Plungers" are devices for removing contact lenses. They are used to touch and directly remove a lens from the eye.

To find the perfect lenses for a person, only a trial and error method can be adopted because different people react differently to lens material and solutions. Also, the power, curvature and diameter of the lenses can be finalized only after wearing the lenses, especially for bifocal or Toric contact lenses.

Before buying contact lenses, it should be verified whether the prescription is the current one with a one-year renewal. A contact lens prescription should contain the patient's name, examination date, power, diameter of the prescribed contact lenses, issue date and expiry date of prescription.

Contact lenses are closer to natural sight than glasses, move with the eye and correct the refractive error to give a more natural field of vision. They can be worn all day and need not be worn on and taken off. Contact lenses stick to the layers of tear fluid and stay in place, the eye lid pressure holds them in place, any impurities sticking to the lens are flushed away by the lubrication in the cornea when the eye blinks.

Contact lenses require some basical care like washing the hands thoroughly with mild soap, rinsing and drying them before handling the lenses so that the hands are free of pollutants. Always use fingertips to handle the lenses. Clean the lenses immediately after removing and the lenses should always be kept in disinfecting solution when not in use and lenses with bacterial or fungal growth should never be worn. Contact lenses provide flexibility and convenience.