What does my prescription(RX) mean?
Your Rx is to correct your vision with a pair of eyeglasses with corrective lenses provided by your eye doctor. You can enter the prescription as follows:
An Rx will have horizontal rows or vertical columns.
OD refers to the right eye and OS refers to the left eye.
SPH, for Spherical, refers to the refractive correction in the prescription. Minus (-) are for nearsightedness, and Plus (+) values are for farsightedness.
Cylinder value indicates astigmatisms or perpetually blurry vision. If there is a CYL value on an eye, there must be an Axis value on that eye. CYL and Axis correct astigmatism.
The Axis indicates the orientation of astigmatism, measured in degrees from 1 to 180.
There may also be a NV-ADD or ADD on the RX, which could be used to order a pair of bifocal or progressive glasses with a close-up vision section in the bottom part of the lens.
Note: The SPH and CYL numbers will always have a plus or minus sign. Please enter correct signs when you place the order.