Have you ever glanced at your glasses or contact lens prescription and felt completely lost?
The combination of numbers, abbreviations, and pluses or minuses can look like a secret code. It’s important to understand what those figures mean, though. This insight can help you feel more in control of your eye health — and ensure you’re getting the right treatment for your vision needs.
At Central Valley Eye Medical Center, our board-certified, fellowship-trained ophthalmologists offer comprehensive eye exams and personalized prescriptions at our offices in Stockton, Manteca, and Modesto, CA. We believe that clear eyesight starts with patient education. Find out what you need to know about your lenses below.
OD, OS, and OU
Let’s start with the basics. “OD” stands for oculus dexter (right eye), and “OS” stands for oculus sinister (left eye). Sometimes you’ll see “OU”, which stands for oculus uterque and refers to both eyes. These labels indicate which eye each prescription applies to.
Sphere (SPH)
This number shows the strength of your lens prescription in diopters. A minus sign (-) means you’re nearsighted (myopia), while a plus sign (+) means you’re farsighted (hyperopia). The higher the number, the stronger the correction needed.
Cylinder (CYL) and Axis
These two figures relate to astigmatism, a common condition caused by an irregularly shaped cornea. The CYL value measures the degree of astigmatism, and the Axis (ranging from 1 to 180) indicates the orientation of the correction on your eye.
Add
This value is often found on prescriptions for bifocal or progressive lenses. It refers to the added magnifying power needed for close-up tasks like reading, usually due to age-related vision changes (presbyopia).
PD (Pupillary Distance)
While not always listed, PD measures the distance between your pupils. This ensures that your lenses align properly with your eyes for optimal clarity and comfort.
Start Making Sense of Your Vision Today
Whether it’s your first pair of glasses or a routine update, knowing what your prescription means helps you take a more active role in your eye care. At Central Valley Eye Medical Center, we’re here to explain every detail and provide precise, high-quality vision correction.
Call +1 (800) 244-9907 to schedule an eye exam at our Stockton, Manteca, or Modesto office.
