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How To Read Your Prescription

Need help reading your prescription? We can help.

We need your complete contact lens or eyeglass prescription to fill your order. All of this information is available on either the package of contact lenses you are wearing or the prescription provided by your eye care professional. Most states require that eye care professionals provide you with a copy if you request it.

Contacts Prescription

  • OD: Right eye OS: Left eye
  • Power: Also referred to as Sphere or SPH (a number between -20 and +20)
  • BC: Base Curve (a number between 8.0 and 10.0)
  • DIA: Diameter (a number between 13.0 and 15.0)
  • CYL: Cylinder (a number between -4.00 and +4.00)
  • AX: Axis (a number between 0 and 180)
  • Brand: The contact lens brand your doctor prescribed to you
Contacts Rx Chart

Eyeglass Prescription

  • OD: Right eye OS: Left eye
  • Sphere: Main prescription strength
  • CYL: Cylinder, indicates astigmatism
  • Axis: Indicates astigmatism
  • Prism: Included in prescriptions to fix diplopia, or double vision
  • Add: For bifocal/progressive prescriptions
  • PD: Distance between pupils
Eyeglass Rx Chart
Find your brand

Need to renew or update your prescription? Take our Online Vision Test

Frequently Asked Questions

How do I know if my prescription is still valid?

The expiration date should be written on the prescription. Under federal law, your prescription is valid for 1-2 years, depending on the state in which your eye care provider is located.

If your prescription is expired, try our online vision test. It only takes about 10 minutes, and you'll have a doctor-approved prescription within 24 hours. It is super convenient, and you don't have to fit a visit to the doctor's office into your schedule.

Do I have to order the brand on my prescription?

The short answer is Yes. The brand is part of the prescription, so you must order the brand your doctor prescribed. You can talk to your eye care provider if you want to try a new brand.

Do I need to send you a copy of my prescription?

You don't have to send us a copy of your prescription, but it will help us ship your order faster. Take a picture of your prescription with your phone and upload it when you place your order, email it to, or fax it to 1-800-401-1495. Please include your order number when you email or fax us your prescription. You can write it on the fax or include it in your email.