Have Two PDs? (e.g. 63/60)
Actually, this is a common point of confusion. In most clinical and optical contexts, when you see two numbers like 31.5 / 30, they are already the monocular PDs, and their sum (e.g., 61.5 mm) is your total PD.
But if you truly see 63/60 on your prescription or measurement sheet, it’s likely that:
- It’s a near PD and distance PD pair (less common notation), or
- There’s a misunderstanding in units or notation.
More Likely Interpretation: Distance PD / Near PD
Some prescriptions list two PD values for different viewing distances:
- Distance PD: Used for regular (far-vision) glasses — e.g., 63 mm
- Near PD: Used for reading glasses — typically 3–5 mm smaller, e.g., 60 mm
This is common for people over 40 who need separate measurements for different tasks.
✅ How to tell which is which?
Check how your eye doctor labeled them:
- “PD: 63/60” might mean Distance / Near
- “Monocular PD: OD 31.5, OS 30” means right and left eye separately
What Should You Use When Ordering Glasses?
It depends on the type of glasses:
| Type of Glasses | Which PD to Use |
|---|---|
| Single-vision (distance) | Use distance PD (e.g., 63) or monocular PDs (e.g., 31.5 / 31.5) |
| Reading glasses | Use near PD (e.g., 60) |
| Progressive / Bifocal | Monocular PDs are strongly preferred (e.g., OD 31 / OS 30) |
If you only have a binocular PD (like 62), most online retailers will split it evenly (31/31)—but if your face is asymmetrical, this can cause discomfort.
Best Practice
- If your prescription includes two numbers, ask your eye care provider to clarify:
→ “Are these monocular PDs (right/left) or distance/near PDs?” - For precision, always request monocular PDs when getting an eye exam—especially if you’re ordering progressives or have a strong prescription.
Let me know your exact numbers and context (e.g., what your optician wrote), and I can help interpret them!
