Read your eyeglass prescription
This guide helps you understand your prescription — but you don’t have to in order to buy glasses.
If you prefer, simply place your order and upload a photo of your prescription: our qualified opticians
will input the values for you and check everything before production. Need advice on lens types or options
(thinner lenses, blue-light coating, photochromic)? Don’t hesitate to contact our opticians.
Visionet is a French online optician with an in-house edging & mounting workshop in Derval (Loire-Atlantique).
Every order is reviewed by an optician before manufacturing.
1Decode in 3 minutes
OD (right eye): SPH −2.00 | CYL −0.75 | AXIS 170° | ADD +1.50
OS (left eye): SPH −1.75 | CYL −1.00 | AXIS 010° | ADD +1.50
PD: 63 mm (31.5 / 31.5)
PRISM: 1.0 Δ Base In (OD)
- OD / OS: right / left eye lines.
- SPH: nearsighted (−) or farsighted (+).
- CYL + AXIS: astigmatism power and its orientation (1°–180°).
- ADD: near addition (for presbyopia).
- PD: pupillary distance used to center lenses.
- Prism: specific correction with a base direction.
You might also see: DV (distance vision) / NV (near vision), PL (0.00), DS (sphere only).
2Quick legend of abbreviations
| Abbrev. | Name | Remember |
|---|
| SPH | Sphere | Overall power: myopia (−) / hyperopia (+). |
| CYL | Cylinder | Power for astigmatism. |
| AXIS | Axis | Astigmatism orientation (1°–180°). |
| ADD / NV | Addition | Extra power for near vision (presbyopia). |
| OD / OS | Right / Left | Two separate lines. |
| PD | Pupillary distance | mm value for accurate lens centering. |
| Δ / Base | Prism / Base | Fixation/diplopia correction (Base In/Out/Up/Down). |
3SPH (Sphere)
Sphere describes nearsightedness (−, blurry far) or farsightedness (+, blurry near).
The higher the absolute value, the stronger the correction.
For higher prescriptions, consider higher-index lenses (1.60 / 1.67 / 1.74) for thinner, lighter lenses.
See our prescription lenses guide.
4CYL (Cylinder) & AXIS
CYL corrects astigmatism (the eye isn’t perfectly spherical). It can be written as + or −.
AXIS shows the orientation of this correction (1° to 180°). The two always go together.
Example: CYL −1.00 AXIS 180° = astigmatism −1.00 oriented at 180°.
5ADD or NV (Near Addition)
ADD is the extra power added to your distance prescription so you can see clearly up close.
It compensates for presbyopia (often after age 40). You’ll see it on reading,
progressive and office/near lenses and it’s often the same in both eyes.
6PD — Pupillary distance
PD is the distance (mm) from the nose bridge to your pupils. It’s used to center your lenses precisely.
It can be binocular (e.g. 63 mm) or monocular (e.g. 31.5 / 31.5 mm).
Don’t have your PD? Follow our guide: how to measure your pupillary distance.
7Prism (Δ) and base direction
A prism can address fixation issues or diplopia (double vision).
It’s written in prism diopters (Δ) with a base direction: Base In/Out (toward nose/temple), Base Up/Down (up/down).
Example: 1.0 Δ Base In (OD). Prism jobs require very precise centering;
our workshop checks each pair with a digital lensmeter.
8Common prescription examples
A. Distance vision (myopia)
OD: SPH −2.50 | OS: SPH −2.00 | PD 62 mm
Single-vision lenses recommended. For thinner lenses, consider 1.60 or 1.67 depending on frame size.
B. Astigmatism
OD: SPH −1.00 CYL −0.75 AXIS 5° | OS: SPH −1.25 CYL −1.00 AXIS 175°
CYL + AXIS always go together. We verify axis values before mounting.
C. Presbyopia (progressives)
OD: SPH +0.75 | OS: SPH +1.00 | ADD +1.75
We do need a fitting height for progressive lenses. In most cases we determine it using an
average frame-wear position, a technique we’ve found performs as well as the traditional in-store method.
D. With prism
OD: SPH −1.50 | 1.0 Δ Base Out
Specific mounting: base direction is double-checked and your prescription is re-read before fabrication.
FAQ — Reading your prescription
Is a glasses prescription the same as a contact lens prescription?
No. Contacts require additional parameters (base curve, diameter, material, and adjusted power due to vertex distance).
Always use the prescription intended for what you’re ordering.
What do PL / DS / VA mean?
PL (plano) = 0.00 D. DS = sphere only (no astigmatism). VA (visual acuity) is the
result recorded during testing (e.g., 20/20).
Do you need a fitting height for progressive lenses?
Yes, we do. We usually determine it based on an average frame-wear position and have found this works
just as well as the traditional in-store approach.
I can’t find my PD — what should I do?
Follow our guide to measure your pupillary distance,
or send us your previous invoice/old pair so our opticians can read the PD.
How do I send a copy of my prescription?
You can upload it while placing your order, or add it after your order from your account.
You can also email it to us after you’ve placed the order. If you need assistance, please
contact us.
Still unsure? Just attach your prescription to the order — we’ll take care of the rest. For anything specific,
contact our opticians.
