Prescription help

How to Read Your Prescription

Prescriptions can be hard to decode. Here's every term you'll see, explained — so you can enter your values with confidence when you build your prescription pair. OD is always your right eye and OS your left.

Your eyes & vision

OD — right eye

Short for oculus dexter, Latin for right eye. The OD row is listed first on your prescription.

OS — left eye

Short for oculus sinister, Latin for left eye.

NV — near vision

Your prescription is for reading and close-up work only.

DV — distance vision

Your prescription corrects your ability to see things far away.

PD — pupillary distance

The distance in millimeters between the centers of your pupils, written as one number (single PD) or two (dual PD). Learn how to find or measure it.

Expiration date

Eyeglass prescriptions are typically valid for one to two years from your exam, depending on your state. Check the date before you order.

Lens powers

SPH — sphere

The main lens power, in diopters, needed to see clearly. A minus sign means nearsighted; a plus sign means farsighted.

Minus (−) numbers

A minus sign next to a number indicates nearsightedness — trouble seeing things far away.

Plus (+) numbers

A plus sign indicates farsightedness — trouble seeing things up close, like reading.

CYL — cylinder

The lens power that corrects astigmatism, which means the cornea or lens of your eye isn't perfectly spherical. If this box is blank, you don't have an astigmatism.

AX — axis

Appears whenever there's a cylinder value. A number from 1 to 180 that sets the orientation of your astigmatism correction.

ADD — addition

For bifocal and progressive prescriptions: the added magnifying power for near vision on top of your distance correction.

Entering your prescription

When you build a prescription pair, enter each value exactly as written — including the plus or minus sign. If your prescription has no cylinder value, leave CYL at 0.00. You'll also upload a photo or PDF of your prescription so we can verify it before making your lenses.

Shop prescription frames

More prescription help

Measure your PD

Find your pupillary distance on your prescription, or measure it at home.

Lens features

What each coating and lens technology does.

Shop prescription frames

Pick a frame, then build your lenses step by step.

Contact us

Questions about your prescription? Talk to a real person.