Sample Prescription:
OD: -1.75 SPH | OS: -2.00 SPH.
OD: -0.50 CYL | OS: -1.00 CYL
OD: 180 AXIS | OS: 90 AXIS
ADD +1.50
Here’s what each part of the prescription means:
OD and OS: These abbreviations stand for “oculus dexter” (right eye) and “oculus sinister” (left eye), respectively. The prescription might include numbers for both eyes, or just one eye if you have different prescriptions for each eye.
SPH (Spherical): This number indicates the main strength of your prescription. It can be positive (+) or negative (-):
A positive number (e.g., +2.00) indicates farsightedness (hyperopia).
A negative number (e.g., -2.00) indicates nearsightedness (myopia).
CYL (Cylinder): This number indicates the amount of astigmatism correction needed. Astigmatism occurs when the cornea is not perfectly round, causing blurred or distorted vision. If you have no astigmatism, this part of the prescription might be left blank or indicated as “SPH.”
AXIS: The axis is a number between 0 and 180 that indicates the orientation of the astigmatism correction needed. It specifies the angle at which the cylinder should be positioned on the lens to correct the astigmatism.
ADD: If you need reading glasses (typically for presbyopia, which is a natural age-related loss of near focusing ability), you might have an “ADD” value. This value is usually positive and indicates the additional power needed for close-up activities like reading. It’s separate from the main SPH value.
PD (Pupillary Distance): This is the distance between your pupils, measured in millimeters. It’s important for accurately positioning the corrective lenses in your frames.
Remember that interpreting your prescription accurately is crucial for getting the right eyeglasses. If you’re unsure about any aspect of your prescription, or if you notice any discrepancies, always consult with your optometrist or eye care professional to ensure you get the correct eyewear for your needs.
