How to Read a Contact Lens Box

Your eye-care provider is required by the Federal Trade Commission's "Contact Lens and Eyeglass Rules" to provide you with a copy of your prescription so you may choose how and from whom you get your contact lenses. Whether you order from a specialty shop, large wholesale store, mail-order catalog or online retailer, it helps to be familiar with your prescription (found on every box of your lenses) so you can easily dispense this information to a seller who is not also your eye-care provider.

Instructions

• 1

  Understand what information is presented in a prescription, including power, base curve, diameter and brand. Bifocals and astigmatism prescriptions typically have additional information.

• 2

  Learn the abbreviations used in a prescription: OS for left eye, OD for right eye, BC for base curve, PWR for power and DIA for diameter. Look for additional abbreviations used for bifocals (ADD for add power) and astigmatism (CYL for cylinder and AXIS for astigmatism).

• 3

  Locate the prescription on the side of the box.

• 4

  Read the measurement of the diameter (DIA), given in millimeters; this is the distance from one edge of the contact lens to the other.

• 5

  Read the power (PWR) of the lens strength (it may be different for each eye), measured in diopters. The higher the power number, the stronger the prescription is. Look for a minus sign to indicate nearsightedness (myopia) and a plus sign to indicates farsightedness (hyperopia).

• 6

  Read the base curve (BC) measurement in millimeters. The lower the number, the steeper the cornea of a patient's eye. If this measurement is not included, it is likely that the brand has only one standard base curve value.

• 7

  Locate the brand name of the contact lens. It is illegal for a contact lens retailer to sell you a different brand from the one prescribed by your eye-care provider.