How to Read Your Prescription
Standard Grid Format
SPH or CYL will always have a (+) or (-) sign.
On any prescription, pupillary distance (PD) can be written in different ways: e.g., 62 (Single PD), 33/31 (Dual PD), or 62/60 (Distance PD/Near PD).
The information on this free-form prescription is usually handwritten.
Progressive / Bifocal
For multi-focal glasses, as well as reading and computer glasses, your Rx will include an ADD or NV (near vision) value for the reading portion. This number always has a (+) sign.
The type of Rx glasses may be noted on a prescription, such as DV [Distance Vision/nearsightedness] and NV [Near Vision/reading].
Prescription with Prism
The less common prism Rx refers to the amount of prismatic power needed to compensate for eye alignment issues (e.g., double vision or “lazy eye”). The prism Rx will have two values: PRISM & BASE.
BO=Base Out, BI=Base In, BU=Base Up, and BD (or BDn)=Base Down.
Unlike typical Rx formats, with values going from left to right, the vertical Rx values are listed top to bottom. This format is less common in the US.
Common Rx Acronyms
- OD = Oculus Dexter refers to right eye.
- OS = Oculus Sinister refers to left eye.
- SPH = Sphere corrects nearsighted or farsighted vision.
- CYL = Cylinder combined with Axis corrects astigmatism.
- PD = Pupillary Distance is the measurement of distance between the pupils.
- ADD or NV ADD = reading power used for a bifocal or progressive
- For complete list of Rx acronyms, click here.