Medical
Eyeglass & Vision Prescription
A vision (eyeglass or contact lens) prescription is the document your optometrist or ophthalmologist issues after an eye exam, specifying the lens power needed to correct your vision. It lists values for each eye — sphere, cylinder, axis, and add — plus pupillary distance for glasses, and is required to order corrective lenses.
Under the FTC's Contact Lens Rule, a contact lens prescription must be valid for at least one year unless there's a documented medical reason for a shorter period.
Written & maintained by the Granite team · Last updated June 2026
Overview
An eye doctor issues your prescription after an exam. Under the FTC's Eyeglass Rule, the prescriber must hand you a copy immediately after a refraction — even if you don't ask — and can't charge a fee or make you buy glasses to get it. That copy is what any retailer, in-store or online, needs to make your glasses or contacts. Eyeglass and contact lens prescriptions differ; contacts also specify base curve and brand.
Prescriptions expire — typically one to two years, set by your state's Board of Optometry and your eye doctor — after which you need a fresh exam to reorder. Keeping the current prescription lets you shop around for frames or lenses without returning to the original provider.
When you’ll get your Eyeglass & Vision Prescription
- You had an eye exam and need glasses or contacts
- You're ordering replacement glasses or contact lenses
- You want to buy eyewear online or from a different retailer
- Your current glasses no longer correct your vision well
- You need your pupillary distance to order glasses online
What’s on your Eyeglass & Vision Prescription
These are the fields Granite reads and extracts automatically the moment you upload one.
- Sphere (SPH)
- The lens power that corrects nearsightedness (minus) or farsightedness (plus), per eye.
- Cylinder (CYL) & Axis
- The correction for astigmatism and its orientation (1–180 degrees), per eye.
- Add
- Additional magnifying power for reading, in bifocal or progressive lenses.
- Pupillary Distance (PD)
- The distance between your pupils, needed to center glasses lenses.
- Prescribing Doctor
- The optometrist or ophthalmologist who issued it.
- Expiration Date
- When the prescription lapses and a new exam is required.
How long to keep it
Keep the current prescription until it expires and is replaced; a copy of recent ones helps track how your vision is changing.
You need the unexpired prescription to order lenses anywhere, and keeping it on hand lets you shop retailers freely. Holding onto past prescriptions also shows how your correction is trending over time — useful context for your eye doctor at the next exam.
How Granite handles your Eyeglass & Vision Prescription
Granite reads your vision prescription — sphere, cylinder, axis, add, PD, prescriber, and expiration — and files it with your medical records. When you want to order glasses or contacts online, every value (including the easily-lost pupillary distance) is one search away, and Granite can remind you before the prescription expires so you're not blocked from reordering.
FAQ
Eyeglass & Vision Prescription: common questions
- How do I read my eyeglass prescription?
- Each eye has values: Sphere (SPH) corrects near- or farsightedness, Cylinder (CYL) and Axis correct astigmatism, and Add is extra power for reading. A negative sphere means nearsighted, positive means farsighted. Glasses prescriptions also include pupillary distance (PD). Contact lens prescriptions differ and add base curve and brand.
- Can I use my eyeglass prescription to buy glasses online?
- Yes. The FTC's Eyeglass Rule requires your eye doctor to give you a copy of your prescription, and any retailer — online or in-store — can fill it while it's valid. You'll also need your pupillary distance (PD) to order glasses online; it's sometimes listed separately, so ask for it if it isn't on the prescription.
- How long does an eyeglass prescription last?
- Typically one to two years, set by your state's Board of Optometry and your eye doctor — most states use two years, while about sixteen use one. After it expires you need a new eye exam to reorder lenses. Check the expiration date on the prescription itself; an expired prescription can't be filled, so tracking the date avoids being stuck when you need replacements.
- What's the difference between a glasses and contact lens prescription?
- They're separate prescriptions. A glasses prescription includes sphere, cylinder, axis, add, and pupillary distance. A contact lens prescription adds base curve, diameter, and a specific brand, because contacts sit directly on the eye. You can't substitute one for the other — ordering contacts requires a contact-specific prescription.
- Can my eye doctor refuse to give me my prescription?
- No. The FTC's Eyeglass and Contact Lens Rules require prescribers to give you a copy of your prescription immediately after the exam, at no extra charge, even if you don't ask. They can't make you buy glasses or contacts, pay a fee, or sign a waiver as a condition of getting it. Keep your copy so you can shop any retailer you like.
Sources
This page is checked against primary and authoritative sources:
Keep your Eyeglass & Vision Prescription in one place.
Drop it in once. Granite reads it, files it, and makes it findable forever — by you today, and by the people who'll need it later.