How to Read a Contact Prescription for Multifocal Lenses

Contact lens prescriptions look like they're written in a foreign language, especially more complicated ones such as multifocal contact lenses. However, they're fairly straightfoward and easy to understand once you've decoded what all the special terminology means. Regardless of whether or not your contacts are multifocal, the simpler your eye problem is, the simpler the prescription will be to understand. If you've got an astigmatism in one or both eyes, you'll have an additional line of prescriptive writing to decipher.

Instructions

• 1

  Examine your contact lens prescription or your soft contact lens box. If you're looking at your contact lens box, it will have the prescription written on it, and you will not need an additional copy of your prescription from your eye doctor (unless you'd like to compare the two).

• 2

  Notice the letters OD and OS written on your prescription. These are abbreviations for the Latin words "oculus dexter" and "oculus sinister," which mean "right eye" and "left eye," respectively. This tells you precisely to which eye each part of your prescription applies.

• 3

  Notice the notation "brand name" next to OD and OS. Just like you'd guess, it's the brand name of contact lens that your doctor has prescribed for you. Depending on the individual needs of your eyes, you may have different brands prescribed for each eye. Check with your eye doctor if you find this confusing.

• 4

  View the other codes on your prescription. "BC" stands for "Base Curve," and will be a number between 8.0 and 10.0. This tells you to what degree your contact lens will be curved to fit each eye. "DIA" stands for "Diameter," which tells you how wide each lens will be from side to side. Next to this, you'll see either the word "Power," the word "Sphere," or the abbreviation "Rx." This is the actual prescription part, and it will be a number between -20 and +20, depending on what each eye's vision correction requires.

• 5

  Look for an additional line that reads "CYL & AXIS" underneath the first line for whichever eye has the astigmatism. "CYL" stands for "cylinder," and will be a number between -4.00 and +4.00. "AXIS" is just that, and will be a number between 0 and 180. Unlike the other parts of your prescription, these two numbers will be written together with an "x" between them." If you read your prescription aloud (for example, when ordering over the phone), this should be read as "times," just like when you're multiplying numbers.

• 6

  Read the words "extra strength" or "add power" on your prescription. This is where your multifocal prescription differs from other types of contact lens prescriptions. It is this phrase that tells the people making your contact lenses how the focal field strength should differ within your lenses. If you have bifocal contact lenses, you will see this notation as well.