How to read my prescription
OD=the right eye
OS=the left eye
SPH=Sphere=Spherical, indicates the amount of lens power, prescribed to correct nearsightedness or farsightedness. If the number appearing under this heading has a minus sign (–), you are nearsighted; if the number has a plus sign (+) or is not preceded by a plus sign or a minus sign, you are farsighted. The larger the number following the +/-, the stronger the prescription.
CYL= Cylinder= Cylindrical, indicates the amount of lens power for astigmatism. This number also has "+" or "-" signs. If "DS" or"SPH" or "spherical" or "PL" is stated at the place of CYL, it means you have no astigmatism.
Axis=a number between 0 and 180 degrees, and indicates the orientation of astigmatism, measured in degrees from 1 to 180. If an eyeglass prescription includes cylinder power, it also must include an axis value, which follows the cylinder power.
Add, short for Reading Addition, is the additional correction required for reading. It can be used to make either reading glasses, bifocal glasses or multifocal glasses.
PD= Pupillary Distance, stands for Pupillary Distance, which is the distance between your pupils in millimeters, Your PD is very important for accurately fitting your lenses to achieve vision acuity.
Prism: refers to the prismatic power used to correct vision displacement. It helps to correct some special conditions or some eye disorders (like squints) that require the focused image to move position. The measurement is Prism Dioptre. The value may be as high as 10 and may go up in steps of ½ or 1 Prism Dioptre’s.
PL: Plano. Latin for "flat." If this is in the SPH section of an Rx, it means no nearsighted or farsighted correction is needed.