Understanding Your Prescription

A clear, practical guide to the numbers on your prescription — and how they help determine the right lenses and Tifosi frame for you.

This guide explains common prescription terms and Tifosi ordering considerations. It
is not medical advice and does not replace an eye examination or recommendations from your optometrist or ophthalmologist.

TOTAL POWER & PD: THE TWO NUMBERS THAT DETERMINE FIT

Every Tifosi Rx-compatible frame has a power range the lab uses to confirm your lenses will sit correctly — clear, centered, and undistorted.

Total Power = Sphere + Cylinder. Use the signed values exactly as written (a negative Cylinder lowers the total, a positive one raises it); no Cylinder means Sphere is your Total Power. Calculate each eye separately — the stronger eye may decide which frames work. (This is a Tifosi compatibility calculation only — it doesn't change your written prescription.)

Pupillary distance (PD) is the distance between your pupil centers, in millimeters, used to position each lens's optical center. Some frames have a minimum PD — so a frame that looks right may not always be the closest optical fit.

Sphere Cylinder Total Power
-2.00 -1.00 -3.00
+4.00 -2.00 +2.00
+5.00 +0.25 +5.25
-2.75 None -2.75

HOW TO READ YOUR PRESCRIPTION

OD = right eye, OS = left eye, OU = both eyes. Blank Cylinder, "DS," or "SPH" means no astigmatism correction — never add a value yourself. Plano (PL) or 0.00 means no spherical correction. View sample prescription

Field What It Means
SPH (Sphere) Main lens power. Minus (–) = nearsightedcorrection, plus (+) = farsighted. Farther from zero = stronger.
CYL (Cylinder) Corrects astigmatism. Enter exactly as written (minus- or plus-cylinder format).
Axis Direction (1–180°) of the Cylinder correction —not a strength. Required whenever Cylinder is present.
Add Extra near-vision power forbifocals/progressives, added to the distance prescription.
Prism Corrects eye alignment. Requires an amount and abase direction (BU/BD/BI/BO).

CHOOSING YOUR LENS DESIGN

Not every progressive wearer needs progressive sport eyewear — many cyclists or runners prefer single vision distance lenses instead. For reading-only lenses, select Single Vision and note "Reading Only" in order notes. Blackout and frosted lenses are also available by request in order notes.

Bifocals are not offered on Rx orders — only on select non-prescription Box Products.

Design Corrects Best For
Single vision distance One range, optimized for distance Driving, cycling, running, golf, everydaydistance
Single vision near One range, optimized for reading/close work Reading, hobbies, detail work
Progressive Distance, intermediate, and near in one lens All-day wear, multiple viewing distances

Additional Details

Balanced lenses: used when one eye has limited usable vision, so the lab matches thickness/weight between lenses. A balanced lens is still clear — it is not the same as a Blackout/frosted lens, which must be requested separately.

Prism: requires both an amount and base direction (BU/BD/BI/BO). Tifosi can accommodate up to 5 prism diopters in many styles, but compatibility varies by frame — these orders may need extra lab review.

Use a current, valid prescription written for eyeglasses — not contacts (the two aren't interchangeable; contacts require a separate fitting). Expiration is governed by state law and the date your doctor wrote; most are valid one to two years. You're entitled to a copy of your prescription and free to use it with any seller.

1. Confirm the document is a current, complete eyeglass prescription with prescriber info.
2. Calculate Total Power (Sphere + Cylinder) for each eye.
3. Confirm your PD in the exact format requested (single or dual).
4. Enter OD/OS values in the correct rows — don't assume both eyes match.
5. Keep every plus/minus sign exactly as written.
6. Enter Cylinder and Axis together when either is present.
7. Choose your lens design based on intended use.
8. Upload a clear image of the original prescription.
9. Note any special requests (Reading Only, Blackout, etc.).
10. Contact the Tifosi Rx team if anything is unclear.