page_title: Eyeglass prescription
section_title: Abbreviations and terms
hierarchical_section_title: Eyeglass prescription / Abbreviations and terms
caption_attribution_description: English: Image of an eyeglass prescription OD: +0.25-1.00x 47, OS: +0.25-0.75x 113, add: +2.50 Image of my own eyeglass prescription. Released under terms of the Wikipedia license.
context_page_description: An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist or ophthalmologist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient. If an examination indicates that corrective lenses are appropriate, the prescriber generally provides the patient with an eyewear prescription at the conclusion of the exam.
  The parameters specified on spectacle prescriptions vary, but typically include the patient's name, power of the lenses, any prism to be included, the pupillary distance, expiration date, and the prescriber's signature. The prescription is typically determined during a refraction, using a phoropter and asking the patient which of two lenses is better, or by automated refractor, or through the technique of retinoscopy. A dispensing optician will take a prescription written by an optometrist or ophthalmologist and order and/or assemble the frames and lenses to then be dispensed and sold to the patient.
context_section_description: Similar to medical prescriptions, eyeglass prescriptions are written on paper pads or included in a patient's electronic health record, and contain a number of different abbreviations and terms:
  DV is an abbreviation for distance vision. This specifies the part of the prescription designed primarily to improve far vision. In a bifocal lens, this generally indicates what is to be placed in the top segment.
  NV is an abbreviation for near vision. This may represent a single-vision lens prescription to improve near work, or the reading portion of a bifocal lens.
  OD is an abbreviation for oculus dexter, Latin for right eye from the patient's point of view. Oculus means eye.
  OS is an abbreviation for oculus sinister, Latin for left eye from the patient's point of view.
  OU is an abbreviation for oculi uterque, Latin for both eyes.
  N.B.: In some countries, such as the United Kingdom, RE (right eye), LE (left eye), and BE (both eyes) are used. Sometimes, just right and left are used.
  SPH, CYL, and AXIS are values for describing the power of the lens using plus cylinder or minus cylinder notation.
  ADD is an abbreviation for Near Addition. This is the additional refractive power to be combined, or added, to the distance power to achieve the ideal near power.
  Prism and Base Prism refers to a displacement of the image through the lens, often used to treat strabismus and other binocular vision disorders.  The prism value is measured in prism diopters, and Base refers to the direction of displacement.
  PD or IPD Pupillary Distance or Interpupillary Distance, respectively. It is the distance between pupil centers.
  BVD Back vertex distance is the distance between the back of the spectacle lens and the front of the cornea (the front surface of the eye). This is significant in higher prescriptions (usually beyond ±4.00D) as slight changes in the vertex distance for in this range can cause a power to be delivered to the eye other than what was prescribed.
caption: An eyeglass prescription
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