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How to Understand Prescription Terms


  • SPHERE is the amount of Near-sighted or Far-sighted correction. (+) PLUS sign signifies that the individual is FAR-sighted. ( - ) MINUS sign signifies that the individual is NEAR-sighted.
  • CYLINDER is the AMOUNT of astigmatism in each eye. AXIS shows the LOCATION of the astigmatism in each eye.
  • ADD refers to how much power is added on for a bifocal or progressive lens, and is also commonly referred to as ADD Power.
  • PRISM is the direction and quantity of shift in image correction to align the eyes.