OD = right eye
OS = left eye
OU = both eyes
SPH or Sphere = lens power for nearsightedness or farsightedness
Minus sign (-) = nearsightedness
Plus sign (+) = farsightedness
CYL or Cylinder = astigmatism correction
Axis = direction of astigmatism correction, measured from 1 to 180
ADD = extra magnifying power for reading or bifocals
Prism = lens adjustment for eye alignment
Base = direction of prism
PD = pupillary distance, the distance between the centers of the pupils
VA or Visual Acuity = vision sharpness
Example: OD -2.00 SPH -1.00 CYL 180 AXIS
Example: OS +1.50 SPH -0.50 CYL 90 AXIS
Example: ADD +2.00
Example: PD 63 mm