How to Compare the Diameter of Frequency & Acuvue Contacts

The diameter of a contact lens is a measurement in millimeters from one edge of the lens to the other. Diameter is important in determining how a contact lens fits on your eyes. Soft contact lenses manufactured by Acuvue and Frequency lenses by Coopervision are available in many different styles, sizes and prescription strengths. Acuvue and Frequency contacts have different diameters which can be measured and compared in several ways.

Things You'll Need

• Millimeter ruler (see Resources)
• Clean towel

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Instructions

• 1

  By law, you are entitled to a copy of your contact lens prescription.

  Obtain a copy of your contact lens prescription if you are comparing Acuvue and Frequency lenses for your own use. The U.S. Food and Drug Administration and Federal Trade Commission stipulate that your eye-care practitioner must give you a copy of your current contact lens prescription.

• 2

  Look for the diameter of the Acuvue or Frequency lens on the written prescription. Your prescription will reference both eyes. OD indicates the right eye and OS represents the left eye. Diameter may be written out or abbreviated as "Dia.," and the size of the lens will follow, written in millimeters---for example, 13.0 or 14.2.

• 3

  Manually measure the size of an Acuvue or Frequency lens with a millimeter ruler (see Resources) if you do not have your written prescription. Lay a clean towel on a flat surface. Place your Acuvue or Frequency lens gently on the towel and place your thumb and index finger over the lens to hold it in place and flatten the contact out as much as possible. Measure across the widest part of the lens to obtain a diameter. Most soft contacts have a diameter of 12.0 to 14.0 millimeters. Measuring the lens this way will give you a close approximation of the diameter of an Acuvue or Frequency lens.

• 4

  Compare the diameter of all Acuvue and Frequency lenses by viewing their product specification sheets (see References). Acuvue provides the diameters of all its lenses on one sheet. Coopervision has separate product specification sheets for each type of Frequency lens. The diameter of each type of lens is listed in a column on the product sheets from both companies.

• 5

  Note the range of diameters in Acuvue and Frequency lenses is similar. Each type of lens fits on your cornea in a slightly different way. The diameter is the size across the lens but is affected by the lens thickness, power and material, which varies with each type of lens. Your eye-care professional determines the proper diameter of the lens by testing several different lenses on your eye for comparison during your initial lens fitting.

• 6

  Compare the differences in the diameters of the two manufacturers' lenses. Your prescription specifies the type of Acuvue or Frequency lens your doctor has determined fits your eye. The various types of Acuvue lenses have diameters ranging from 14.0 to 14.5 millimeters. Frequency lenses are available in diameters from 14.0 to 15.5, depending on the type.