A contact lens is used instead of the traditional glass although it serves the same corrective purpose as that of an eyeglass. The idea of contact lens was first written by Leonardo da Vinci. In one of his books he had mentioned about changing corneal power by immersing the eye in a bowl of water. Present day soft lenses were invented by Otto Wichterle and Drahoslav Lim, who were chemists from Czech.

Many people prefer contact lens as it is lightweight and invisible. Contact lenses are usually placed on the cornea of the eye. It is very important to wash hands with a non-moisturizer or non-allergen soap before inserting the lens into the eyes as it may destroy the natural bacteria found on the eye. While inserting contact lens into the eyes, the lens has to be placed on the index finger with the concave side upward. The inserting and removing technique may vary depending on the nature of the lens which could be either soft or rigid.

Daily disposable contact lens requires no cleaning. But there are some types that require regular cleaning to avoid infection. Multi purpose solution, saline solution, hydregen peroxide solution, daily cleaner and enzymatic cleaner are products available in the market to clean your contact lenses.

Practicality and appearance are the two main reasons for using contact lens. There are many advantages in using contact lens when compared to glasses. Contact lens provides a wider field of vision; do not get affected by wet weather, best suitable for sporting activities. There are some conditions like Keratoconus and Aniseikonia that can be rectified only with contact lens and not by the traditional spectacles.

Contact lens are also called as contacts which can be either:

- Corrective lens
- Cosmetic lens
- Therapeutic lens

Corrective contact lenses: A corrective contact lens is used to rectify the refraction error in the eye. Some people suffer due to this problem, which arises because of mismatch between refractive power and the length of the eye. This mismatch can be rectified by contact lens, which neutralizes and allows correct focus of light onto the retina. The other eye related problems that can be rectified are Myopia, Hypermetropia, Astigmatism and Presbyopia. People with certain color defiency use a red tinted X-Chrom contact lens which helps them in distinguishing colors better.

Cosmetic Contact lenses: This type is usually designed in many colors which aim to change the appearance of the eye.  Sometimes it is used to correct the vision too. This type of lens might initially cause some irritation in the eye but on the long run it tends to cause no damage. Theatrical contact lenses and scleral lenses are types of cosmetic lenses generally used in the enteretainment industry.
Therapeutic lens: These are soft lens used to rectify the non-refractive disorders of the eye. These are also used in the treatment of Bullous Keratopathy, Corneal Ulcers, Corneal Edema, Corneal Ectasis, dry eyes and anterior Corneal Dystrophy.

Contact lenses should be bought from a reliable store and it is always good to go for a branded one. Utmost care should be taken in using contact lens.