contact lens prescription

Understanding the details of your contact lens prescription is not imperative, but it is important to have a basic grasp of the information so that you can better understand your specific vision problem and how it is being remedied. Furthermore, it can be useful to know what the abbreviations and measurements are if you ever need to double-check that you have been given the correct prescription or if you need to talk about issues you are having with your contacts with your eye care professional.

Below is an outline of a sample contact lenses prescription. The sample includes descriptions for categories of information presented. Not every contact lens prescription will contain all of this information; some information is specific to certain conditions.

OD/OS

This is an abbreviation for Oculus Dexter and Oculus Sinister, meaning the right and left eye respectively.

PWR

This refers to the amount of correction the lens must provide to increase your visual clarity to an acceptable level (usually 20/20 is the goal).  A negative value in this area would indicate nearsightedness (myopia) and a positive value would indicate farsightedness (hyperopia). Zero is the 20/20 standard and the farther the value is from zero, the more correction is necessary for visual clarity. It is not unusual for the values in the left eye and right eye to differ in correction power.

BC

This refers to the measurement of the back curvature of your contact lens, this measurement is used to determine which contacts will best fit the natural curve of your cornea, which was measured during your eye exam.

DIA

This is the distance from one edge of the contact lens to the other edge of the contact lens. This will determine where on your eye the edges of the contact lenses will sit.

CYL

This is used if you have astigmatism and measures how much astigmatism you have. A negative value indicates a myopic astigmatism and a positive value indicates a hyperoptic astigmatism.

AXIS

This measurement is used if you have astigmatism and is used to indicate the cylinder powers orientation on the lens to accommodate for the cornea’s irregular shape when astigmatism is present.

ADD

This refers to the increased magnifying power added to bifocal contact lens portions to aid in reading and detailed work.

COLOR

This is used to indicate the color if colored contacts are being used.

BRAND

This is used to indicate the brand that the eye doctor has determined best suits your eye care needs.

This is an outline of information often contained in a contact lens prescription.  Specific values have been left out since there are too many variations and it could distract from a general discussion.  If you have specific questions about your contact lens prescription and the meaning of the numerical values in these categories, do not hesitate to discuss them with your eye care professional.