Your Contact Lense Prescription in English

If you've ever looked at a contact lense prescription, you might think you need a medical degree to understand it.  However, it's not that difficult, if you know what the codes mean.  Plus, it is important to know what your prescription says about your eyes. 

Up until just a few years ago, eye care professionals were not required to give their customers a copy of their contact lense prescription.  Thanks to legislation passed in 2004, consumers now have the right to receive a copy of their prescription at the end of their doctor's visit.  This gives the consumer the freedom when ordering contact lenses, so that they can compare contact lense prices from their doctor with prices online.  Usually, but not always, it is cheaper to purchase contact lenses online. 

However, along with this freedom comes responsibility.  Since contact lenses are considered to be medical devices, it is extremely important to have an updated contact lense prescription before ordering contact lenses online.  The prescription tells much more than just your vision.  It also tells the contact lens supplier the measurements that will best fit your eye. 

If you don't use the proper prescription, it can result in blurry vision, discomfort, and even infection.  For that reason, you can not just use a previous prescription for eyeglasses, or copy a friend's prescription that has similar vision to yours.  And, for that reason, when you order contact lenses online, they will require an updated contact lense prescription. 

However, once you get your prescription, you might look at it and wonder what all those codes and numbers mean.  The brief explanations below will help you understand what it all means.  

OS/OS/OU
OS:       The measurements for your left eye
OD:      The measurements for your right eye
OU:      If you see this on your prescription, it means that the measurements are the same for both of your eyes.

PWR
This is the strength of your contact lens; for example, -1.25, -1.00, +1.75, +3.0, etc. 

BC
This stands for “base curve,” which is the inside curve of your lense and is prescribed to match the curvature of the cornea. 

DIA
This stands for “diameter.”  It is the diameter, or the distance from one edge of your lense to the other; basically, it tells how big your lense is.  This is one of the measurements that it’s important to fit your eye specifically; otherwise your lens can cause abrasions and discomfort. 

BRAND
This is the brand name of the contact lens that the provider is selling you.

ADD
This stands for “added power” and is used for bifocal or multifocal contact lenses.  It is the added power required for reading at a near distance. 

CYL
This stands for “cylinder;” this number indicates that you have astigmatism, as well as the extent of your astigmatism. 

AXIS
This number also indicates that you have astigmatism; it determines the orientation of your astigmatism.   It is the part that is used to compensate for the oval shape of the cornea. 

COLOR

This is only used if you want tinted or colored contact lenses.

See?  It's not that complicated.  Now, you can fully understand exactly what your contact lense prescription says about you! If you want to keep current with the site updates, subscribe to our blog so you don’t miss any of the news!

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