Deciphering your Prescription

Contact lenses are a medical device which require a prescription … even if they are not for vision correction. When you have an eye exam, your eye care professional will assess the health of your eyes and also check for nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Your eye care professional will measure your vision precisely, and, if necessary, determine a prescription for corrective lenses.

Have you ever wondered what all of the numbers and abbreviations on your contact lens prescription mean? Here's a guide to help you decipher your prescription.

O.D. right eye
O.S. left eye
Power (PWR): Strength of your contact lens (e.g., -1.00, -1.25, +1.50, +3.00, etc.)
Base Curve (BC): Inside curve of your contact lens (e.g., 8.0, 8.1, 8.2, etc.)
Diameter (DIA): Size of your contact lens (e.g., 13.8, 14.0, 14.2, etc.)
Cylinder (CYL): Strength of your astigmatism (e.g., -0.75, -1.00, -1.25, etc.)
Axis (AX): Orientation of your astigmatism (e.g., 170, 160, etc.)
 ADD  Low or High add power for near vision for presbyopic lenses


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