How to Read a Prescription for Glasses

Having a hard time figuring out your prescription so you can order glasses online?

Reading Prescriptions for Glasses

Glasses PrescriptionEyeglasses prescriptions can be pretty hard to look at if you’ve never had to read one before, and entering your information online can be nerve-wracking if you’re not sure you’re doing it right.

If you want to learn how to read a prescription for glasses, there are a few basic components that you can dissect it into:

  • First, there is your “distance” prescription, which is generally a grid on the top of your prescription. This grid should have two rows labeled “OD” and “OS”.
  • OD stands for right eye, and OS stands for left eye. Each eye should have spaces labeled for Sphere (or SPH), Cylinder (or CYL), and Axis. While each eye does not have to have numbers for all of these, there should be at least one number for each eye; these make up your distance prescription, or your prescription for seeing far away.
  • This distance prescription area may have “SPH” written in a Cylinder area. This means there is no cylinder, or cylinder is zero. Also, you can have sphere without cylinder or axis, but you cannot have cylinder without axis or axis without cylinder. Cylinder and axis work together.
  • The numbers for your cylinder and axis are either positive (+) or negative (-) and always have two numbers after the decimal place. In other words, if your doctor writes, “-025″ for your sphere, that means “-0.25,” “+300″ means “+3.00,” and so on. Axis is a number between 0 and 180 that isn’t marked positive or negative.
  • Second, there is your bifocal prescription, which should be just below your distance prescription. This is only for people who have a separate prescription for near and far viewing. This will generally be labeled as, “ADD,” “Bifocal,” or “Addition,” and it will be another number with two numbers after the decimal place, such as “+1.25.” It will ALWAYS be positive.
  • Third, there is your pupil distance. This may be in any number of places on the prescription, either at the top, in the middle, at the bottom, or on the back of the page. Sometimes the doctor does not mark it. It is typically labeled “PD” or “Pupil Distance.”
  • If your pupil distance is not marked on your prescription, you can often call your doctor for it or measure it yourself. PD is the distance between your pupils while you’re looking straight ahead, and it’s measured in millimeters.

These are the basic components necessary to be able to read your prescription and enter the information into a form online to order prescription glasses.



If you’re still confused about how to read your prescription for glasses, don’t feel bad. Many people contact us regularly to ask how to understand their prescription while entering it in online.

If you need more help with your glasses prescription, you can give us a call or leave a comment below. Thanks for reading, and happy shopping!

10 Responses to How to Read a Prescription for Glasses
  1. Ibrahim
    August 30, 2014 | 1:06 pm

    hi i was wondering if you can tell me if this is right


    R -150 -100 x 130

    L -150 -075 x 045

    is this how I would write it in proper form?

    R -1.50 -1.00 x 130

    L -1.50 -0.75 x 45

    if you can help me out i would really appreciate it


  2. Jessica Anne
    September 3, 2014 | 4:58 pm

    When you enter the prescription on our website we only allow a pull down for the prescription numbers so if that is how the doctor wrote it then enter it like that on our website.

  3. Shellie
    September 30, 2014 | 1:31 am

    My son went to the eye doctor today. When he takes the exams for nearsightedness he fails. I’m look at prescription and to me it seems like the DR wrote it for nearsightedness. Am I wrong?

    +0.75 -1.00 101
    +0.50 -1.25 81

    ADD 0

    I’m so confused and need to understand.

  4. Jessica
    October 6, 2014 | 2:26 pm

    Nearsightedness is when you see objects close to you clear but objects far away are blurry. When the doctor wrote the prescription he wrote it for nearsightedness. When a + sign is in front of the RX then that means that he needs glasses to do things such as reading…when a – sign is in front of the RX then that means he needs glasses for things far away. I hope this helps you. If you are at all doubting what the doctor wrote then go back and have him check it because if you get glasses and have the RX put in and the doctor wrote the wrong RX then most likely YOU will have to pay additional to have the correct lenses put in and most doctors will not pay for their mistake.

  5. Jo-Ann
    July 13, 2016 | 7:15 pm

    Sphere. Cylinder. Axis. Add
    Dr. wrote this week:
    R. +1.50. -0.50. O55. +200
    L. +1.25. Sphere
    Dr. wrote 5 months ago:
    OD +3.00
    OS. +3.00
    Please let me know what is happening. I’m really confused. I made new reading glasses 41/2 months ago. Do I now need new reading glasses?
    Thank you,

    • Ryan Phillips
      July 15, 2016 | 2:38 pm

      Prescriptions change, and that must be the case here with you. You probably need new glasses, but you should consult with your doctor.

  6. Cassandra
    November 14, 2016 | 2:33 am

    Do I really need glasses or are they just trying to get a sale

    Sphere is -.025 cy is -.075 both eyes

    • Ryan Phillips
      November 16, 2016 | 3:20 pm

      Hi Cassandra,

      You do have a slight correction for distance and astigmatism. I don’t see why they would damage your eyes just to make a sale. I know people who have gone to the eye dr and be told they have perfect vision and don’t require glasses.

  7. Geri
    May 30, 2017 | 5:21 am

    If my spherical od is pl and my os is +0.25, do I need bifocals.

    • Ryan Phillips
      June 6, 2017 | 1:09 pm

      Hi Geri,

      If you require a bifocal, it would be listed on your prescription as ADD. It sounds like the PL and the +0.25 are your sphere corrections, which indicate whether you are nearsighted or farsighted.

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