How to order glasses online with a foreign prescription from home

If you have a prescription from China, Korea, Japan, or another Asian country, you might wonder if it can be used to buy glasses online from retailers like NextPair or other Western optical stores.

✅ The good news: You can use an Asian prescription, but you need to check a few things before ordering to ensure accuracy.

🔍 Key differences to be aware of:

• Prescription formats may differ (decimal vs. fraction measurements).

• PD (pupillary distance) may not be included in Asian prescriptions.

• Cylinder & axis values for astigmatism may be recorded differently.

Let’s go step by step to ensure your foreign prescription works smoothly when ordering online.

Understanding Your Prescription Format

When ordering glasses online with a foreign (Asian) prescription, the first and most crucial step is understanding how prescription formats differ between Asian countries and Western optical retailers. If you enter your prescription incorrectly, you might end up with glasses that don’t correct your vision properly.

Here’s what you need to check:

👁️ 1. Sphere (SPH): Checking Your Prescription Strength

The sphere (SPH) value represents the strength of your prescription. It determines whether you are nearsighted (-) or farsighted (+).

How It’s Recorded in an Asian Prescription:

• The SPH value is usually written as a decimal (e.g., -4.25 or +2.00).

• Some Asian prescriptions may omit the plus (+) sign for farsightedness (e.g., "2.00" instead of "+2.00").

How to Enter It Online:

✅ Use the exact number as written.
✅ If you are farsighted and there is no plus sign (+) on your prescription, add one manually when entering it.
✅ If your prescription only lists SPH and nothing else, it means you don’t have astigmatism and can ignore the Cylinder (CYL) and Axis sections when ordering.

🟡 Example Conversion:

• Asian Prescription: SPH -5.50

• Enter Online: SPH -5.50 (no change needed)

• Asian Prescription: SPH 2.00

• Enter Online: SPH +2.00 (add the + sign if missing)

🔄 2. Cylinder (CYL) & Axis: Adjusting for Astigmatism

If you have astigmatism, your prescription will include Cylinder (CYL) and Axis values.

How It’s Recorded in an Asian Prescription:

• Some Asian prescriptions use positive (+) CYL values, while Western retailers use negative (-) CYL values.

• The Axis value (0°–180°) may not always be included in an Asian prescription if astigmatism is mild.

How to Enter It Online:

✅ If your CYL is negative (-) in your prescription, enter it as is.
✅ If your CYL is positive (+) in your prescription, you must convert it to a negative (-) value and adjust the Axis.

🟡 Example CYL Conversion:

• Asian Prescription: CYL +1.00, Axis 10°

• Western Conversion: CYL -1.00, Axis 100° (add 90° to Axis)

• Asian Prescription: CYL +2.50, Axis 90°

• Western Conversion: CYL -2.50, Axis 180°

If your Asian prescription does not include an Axis value, contact your optician before ordering—missing Axis values can cause blurry vision.

📏 3. Pupillary Distance (PD): Measuring If It’s Missing

Pupillary Distance (PD) measures the space between your pupils (in millimeters). This ensures that the optical center of the lenses aligns with your eyes.

How It’s Recorded in an Asian Prescription:

• Many Asian prescriptions do not include PD because local opticians measure it only when ordering lenses.

• If PD is included, it is often written as a single number (e.g., 63mm) or two separate values (e.g., 31mm/32mm for each eye).

How to Measure PD Yourself If It’s Missing:

If your prescription doesn’t list PD, you can measure it at home using a mirror and a ruler:

1️⃣ Stand in front of a mirror and hold a ruler against your forehead.
2️⃣ Look straight ahead and measure the distance from the center of one pupil to the center of the other (in millimeters).
3️⃣ If you have two separate values (one for each eye), measure from the bridge of your nose to each pupil.

🟡 Average PD Range:

• Adults: 58mm–70mm

• Children: 48mm–55mm

🟡 Pro Tip: NextPair has a PD measurement guide to ensure accuracy before ordering.

👓 4. Prism Correction: Check If Your Prescription Includes It

If you have an eye alignment issue (like strabismus or double vision), your prescription might include prism correction values.

How It’s Recorded in an Asian Prescription:

• Some Asian opticians do not include prism correction unless specifically requested.

• If present, it will be written as a small number (e.g., 1.00) along with a base direction (e.g., Base In, Base Out, Base Up, Base Down).

How to Enter It Online:

✅ Enter prism correction exactly as written—including the base direction.
✅ If your Asian prescription does not include prism values, confirm with your optician before ordering.

Checklist: Before Entering Your Prescription Online

✅ SPH is correctly entered (add + sign if necessary).
✅ CYL is converted from positive (+) to negative (-) if needed and Axis is adjusted by 90°.
✅ PD is measured and entered correctly if not included in the prescription.
✅ Prism correction is entered if applicable.
✅ Upload a copy of your prescription if the retailer allows it (NextPair will verify for accuracy!).

🟡 Pro Tip: If you’re unsure about any values, NextPair’s customer support can always help you double-check your prescription before placing an order.

By ensuring your prescription is correctly formatted, you’ll avoid delays, errors, and the hassle of returns—so you can get your new glasses faster and with perfect vision clarity! 👓🟡