How To Read Your Rx

OD (Right) Acuvue Oasys for Astigmatism 8.8 14.0 -2.25 -1.25 160    
OS (Left) Acuvue Oasys for Astigmatism 8.8 14.0 -3.00 -1.75 180    

Below is a glossary of prescription terms:

Eye – Refers to which eye the prescription line item is for. The OD (oculus dexter) means Right Eye, while OS (oculus sinister) refers to Left Eye. OU (oculus uturque) refers to both eyes.

Brand – The specific brand or type of contact lens that the eye doctor is prescribing.

BC – This stands for Base Curve, and is the measurement of the inside curve of the contact lenses. It is usually a number between 8 and 10 and is sized to match or correct the curvature of the eye.

DIA – Short for Diameter, this measurement refers to the size from edge to edge of the contact lens. Soft contact lenses are larger than RGP lenses; for both, the diameter is usually between 13 and 15.

SPH – Also referred to as Power or PWR, this field references the corrective factor of the contact lenses. A negative number, such as -2.25, in this field indicates myopia, (nearsightedness), while a positive number like +2.25 indicates hyperopia (farsightedness). If the prescription shows the letters PL, which stands for Plano, it means the no correction is needed.

CYL – This measurement, which stands for Cylinder, shows how much astigmatism, if any, the patient may have. It is measured in diopters.

AX – Short for Axis. Measured in degrees, the axis references the placement of the power in the lens, to compensate for the cornea’s shape when there is astigmatism.

ADD – Used for multifocal or bifocal contact lenses, the number here, measured in diopters, adds a degree of magnification to certain portions of the lens.

Color – The customer’s requested tint, if any.