OD or O.D. = right eye
OS or O.S. = left eye
OU = both eyes
SPH or Sphere = lens power for nearsightedness or farsightedness
Minus sign (-) = nearsightedness
Plus sign (+) = farsightedness
CYL or Cylinder = amount of astigmatism correction
Axis = direction of astigmatism correction, from 1 to 180
ADD = extra magnifying power for reading or near vision
Prism = lens adjustment for eye alignment
Base = direction of prism
PD = pupillary distance
VA = visual acuity
NV = near vision
Distance = prescription for seeing far away
Near = prescription for reading or close work
Example: -2.00 SPH = 2 diopters of nearsighted correction
Example: +1.50 SPH = 1.5 diopters of farsighted correction
Example: -1.00 CYL x 90 = 1 diopter of astigmatism correction at axis 90
Example: ADD +2.00 = 2 diopters added for near vision
Single vision = one prescription for one distance
Bifocal = two vision zones in one lens
Progressive = gradual change from distance to near vision
Lens power is measured in diopters
Higher absolute numbers mean stronger lenses
A blank CYL or AXIS usually means no astigmatism correction
A prescription may list different values for each eye
PD may be written as one number or two numbers
Prism may be written in prism diopters or with base direction
If unsure, confirm the prescription with your eye care provider