The contact lens is medical equipment in the form of a lens used as a corrective or cosmetic measure which is placed on the cornea of the eye. They usually serve the same therapeutic purposes as spectacles, but their advantages include being of light weight and also being virtually invisible to others. However, some contact lenses are purposely colored to change the appearance or the color of the eye. According to research, it is estimated that nearly one hundred and twenty five million people all over the world, now use contact lenses, with at least twenty eight million people in the United States alone.
People might choose to wear contact lenses over the use of spectacles due to many practical reasons. Contact lenses are less affected by outdoor weather conditions as compared to glasses and do not fog up and provide a much wider field of vision to the user. They are especially suitable for playing outdoor sports or for rigorous outdoor work or travelling. There are also some specific eye related ophthalmological conditions such as Aniseikonia or Keratoconus which cannot be perfectly corrected by using spectacles.
There are different types of these contact lenses. The Corrective Contact Lenses are used by those who wish to improve vision. Most of these people suffer from a refractor error, which occurs when there is an imbalance of the refractive power and the length of the eye. A contact lens thus helps to improve the condition of this mismatch. For those people who suffer from colour deficiencies, they use red tinted contact lenses, this may not completely cure their colour blindness, but it does help them to distinguish between colours better.
Cosmetic contact lenses are used solely to change the colour or appearance of the eye, and have very little corrective effects. They are usually proven to cause no long term damage to the eye but may cause a little irritation and blurring of vision from time to time, and must thus be worn as little as possible.
The Therapeutic lenses are the soft lenses that are used to treat and manage the non refractive defects of the eye of a patient. There are contact lenses of the bandage variety, which covers an infected or injured cornea, this protects the cornea from impurities around it or the constant rubbing caused due to the blinking of eyelids and thus allows it to heal.
