How to Read Your Eyeglasses Prescription
Eyeglass prescriptions may look complicated at first, but most of them use the same basic abbreviations and measurements.
Understanding these terms can help you enter your prescription correctly when ordering glasses from Rimcoo.
Always enter your prescription exactly as written, including all plus (+) and minus (-) signs.
1. Understanding Your Prescription
Your prescription may be printed on paper or provided digitally. It usually appears as a chart containing rows for each eye and columns for different prescription values.
OD, OS and OU
These abbreviations identify which eye the prescription refers to:
- OD – Right Eye
- OS – Left Eye
- OU – Both Eyes
Some prescriptions may use RE for Right Eye and LE for Left Eye instead.
SPH – Sphere
SPH indicates the main lens power used to correct nearsightedness or farsightedness.
- A minus (-) value usually indicates nearsightedness.
- A plus (+) value usually indicates farsightedness.
In general, the larger the numerical value, the stronger the prescription.
CYL – Cylinder
CYL indicates the amount of correction required for astigmatism.
It may appear as either a plus (+) or minus (-) value depending on how the prescription was written.
If the CYL field is blank, astigmatism correction may not be required for that eye.
Enter SPH and CYL exactly as written on your prescription. Do not change plus (+) values to minus (-), or minus (-) values to plus (+).
AXIS
AXIS describes the orientation of astigmatism correction and is measured from 1 to 180 degrees.
If your prescription includes a CYL value, it will normally also include an AXIS value.
ADD – Addition
ADD is additional lens power used for near vision.
It is commonly found on prescriptions for progressive, bifocal, multifocal, or reading lenses.
ADD is usually shown as a plus value, such as +1.50, +2.00, or +2.50.
PD – Pupillary Distance
PD stands for Pupillary Distance and is the distance between the centers of your pupils, measured in millimeters.
It may appear as:
- Single PD – for example, 63 mm
- Dual PD – for example, 31.5 / 31.5 mm
Dual PD represents the distance from the center of the nose to each pupil separately.
PD helps position your lenses correctly in front of your eyes.
2. Eyeglasses Prescription Examples
Prescription formats can vary, but the examples below show several common types of eyeglass prescriptions.
Example 1: Nearsightedness (Myopia)
A nearsighted prescription usually contains minus (-) SPH values.
| Eye | SPH | CYL | AXIS | ADD |
|---|---|---|---|---|
| OD | -2.00 | — | — | — |
| OS | -1.75 | — | — | — |
In this example, both eyes have minus SPH values, indicating correction for nearsightedness.
Example 2: Farsightedness with Astigmatism
A farsighted prescription usually contains plus (+) SPH values. If CYL and AXIS are also present, the prescription includes astigmatism correction.
| Eye | SPH | CYL | AXIS | ADD |
|---|---|---|---|---|
| OD | +1.50 | +0.50 | 90 | — |
| OS | +1.75 | +0.75 | 85 | — |
In this example, the SPH values are positive, while the CYL and AXIS fields provide additional correction for astigmatism.
Example 3: Progressive Lenses
A progressive prescription normally includes an ADD value in addition to the distance prescription.
| Eye | SPH | CYL | AXIS | ADD |
|---|---|---|---|---|
| OD | -1.50 | -0.50 | 95 | +2.00 |
| OS | -1.25 | -0.25 | 85 | +2.00 |
The ADD value provides additional near-vision power and is one of the key pieces of information needed when ordering progressive lenses.
Eye-care professionals may use slightly different formats, but the main prescription values are generally similar.
3. A Few Reminders
- Your eyeglasses prescription is different from a contact lens prescription.
- Use a current, valid prescription when ordering prescription lenses.
- Always enter the prescription values exactly as written.
- Pay special attention to plus (+) and minus (-) signs.
- Do not guess or change any missing prescription information.
You can send us a clear copy of your prescription and we'll help you understand the information needed for your order.
Need Help?
If you have questions about reading or entering your eyeglasses prescription, please contact us.
Email: service@rimcoo.com