page_title: Contact lens
section_title: Prescriptions
hierarchical_section_title: Contact lens / Prescriptions
caption_attribution_description: English: Contact Lens base curve and diameter The Base curve is the measurement of the radius of curvature in millimeters of the inside curve. The lenses diameter in millimeters. This picture is a reconstruction of a lens where d = 14 mm and BC = 8.4 mm. Svenska: Kontaktlinsers specifikationer Baskurvan (BC) är radien på den cirkelbåge som motsvarar linsens insida. Ju större baskurvan är desto planare är linsen. Diametern (d) är linsens yttermått Både diametern och baskurvan anges i millimeter. Det uppritade linsen på bilden har diametern 14 mm och baskurvan 8.4 mm
context_page_description: Contact lens, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic or therapeutic reasons. In 2010, the worldwide market for contact lenses was estimated at $6.1 billion, while the US soft lens market was estimated at $2.1 billion. Multiple analysts estimated that the global market for contact lenses would reach $11.7 billion by 2015. As of 2010, the average age of contact lens wearers globally was 31 years old, and two-thirds of wearers were female.
  People choose to wear contact lenses for many reasons. Aesthetics and cosmetics are the main motivating factors for people who want to avoid wearing glasses or to change the appearance of their eyes. Others wear contact lenses for functional or optical reasons. When compared with spectacles, contact lenses typically provide better peripheral vision, and do not collect moisture or perspiration. This can make them preferable for sports and other outdoor activities.
context_section_description: The parameters specified in a contact lens prescription may include:
  Material / Brand name
  Base curve radius (BC, BCR)
  Diameter (D, OAD)
  Power in diopters
  Center thickness (CT)
  Prescriptions for contact lenses and glasses may be similar, but are not interchangeable. Prescribing of contact lenses is usually restricted to various combinations of ophthalmologists, optometrists and opticians. An eye examination is needed to determine an individual's suitability for contact lens wear. This typically includes a refraction to determine the proper power of the lens and an assessment of the health of the eye's anterior segment. Many eye diseases prohibits contact lens wear, such as active infections, allergies, and dry eye. Keratometry is especially important in the fitting of rigid lenses.
caption: Diameter and base curve radius
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