All About How to Read Your Contacts Prescription

Doctors seem to have their own language and your eye doctor is no exception to that rule. These men and women spend years studying the human eye and all it encompasses. Understanding their language can be a challenge and it is likely you will never understand everything, but one part that is easy to understand is your Contacts Prescription. If you have regularly looked upon your prescription and scratched your head in confusion, read on and we will tell you what it all means.


It would be great if everything on your Contacts prescription was in plain English, but that is not the case. Medical terms are often derived from their Latin roots. OD and OS on your prescription is an example of this. OD is Oculus Dexter which is Latin for right eye. Oculus Sinister or OS is Latin for left eye. The OD will generally come above and/or before the OS on your prescription. OU is Oculus Uterque which means both eyes. Those with different prescriptions for each eye will see OD and OS while those with the same prescription in both eyes will see OU.


Another bit of information found on your Contacts prescription is located just below the previous, OD/OS/OU terms. PWR and SPH refer to Power and Sphere. This is where the strength of the prescription is noted. For the sphere you will see a minus (–) indicated nearsightedness and plus (+) is farsightedness. PL or Plano in this area means 0.00 Power or Sphere & the eye does not need correcting.

The Power of your lenses is denoted in diopters ranging from +0.25 or -0.25 and beyond. The farther away that number is from zero, the stronger your prescription is.


Contacts Prescriptions for Astigmatism or Toric like BioTrue ONEday for ASTIGMATISM manufactured by Bausch and Lomb have the amount listed in minus (-) CYL (Cylinder). Usual CYL amounts will start at -0.75 and go up to -2.75 depending on the brand of Contacts.


A Multifocal or for Presbyopia Contacts Prescription like Biotrue ONEday for PRESBYOPIA Multifocal by Bausch and Lomb will have the ADD with plus (+) near power listed as Low, Medium (Mid) or High or might be listed from +0.75 up to +2.50.


Base curve of BC noted on your Contacts Prescription indicates the curve of the lenses over the eye. The number ranges from 8 to 10 on average and the lower the number, the steeper the curve. Adversely, the higher the number, the shallower the curve will be.


Shortening words is what doctors are best at and DIA on your prescription is short for diameter. Although most people assume the diameter of every Contact lens is the same, there are some differences. Diameters are measured in millimeters and will vary depending on the type of Contacts you are prescribed.

Brands do Matter

Those new to the world of Contacts may be under the impression that they can get any brand they want as long as it is available in their Contacts Prescription strength. Contact Lenses are legally regulated by the FDA which requires that in order for your Contacts Prescription to be filled it must have the brand listed on your Contacts.  So, if you have a specific brand in mind, let your Eye Doctor know before they hand you your Contacts Prescription. Also, a Glasses Prescription cannot be used to fill an order for Contacts.  A Contacts Prescription is required to order any Contacts from any Contacts Retailer.

Lens Experts

At Lens Experts we are here to help you. When you doctor gives you your Contacts Prescription, you can upload it or email to Lens Experts Website when you order so you do not have to run down to a pharmacy or Doctors office to order.  We process your transaction and our goal is 100% accuracy to get you your correct Contacts sent directly to your door asap. Let Lens Experts make your Contacts easy as 1,23!  Now that you know about how to read your Contacts Prescription, you can buy your Contacts from us at Lens Experts.

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