How to Read
My Prescription
When you leave your eye doctor's office and look at your prescription, it may seem like an unrecognizable series of numbers and abbreviations. It makes ordering prescription glasses online challenging and overwhelming. Let's take a moment to decipher and understand what’s on your prescription. Let's get started.
Have NV/DV/SV on your prescription?
NV stands for near vision for reading use or computer use.
DV stands for distance vision for constant wear or daily use. Doctors usually use this to distinguish different usage.
SV means single vision. Doctors use this to tell you that you need single vision lens instead of bifocal or progressive lens.
How To Read Eyeglasses Prescriptions?
Then you need to know OD and OS. OD means 'right eye' and OS means 'left eye'.
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SPH |
SPH stands for sphere or spherical power. This indicates the amount of lens strength. There will be a plus sign for farsighted and negative sign for nearsighted - followed by a number. The larger the number, the stronger the prescription you needed to correct your vision. |
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CYL and AXIS |
If you have astigmatism, CYL and AXIS will be full in your prescription. Astigmatism is where the eye is not completely spherical but shaped more like a football. CYL or cylinder is the degree of how flat your eye is. The higher the number, the more astigmatism you have. The AXIS represents the orientation or angle of your astigmatism. From 1 to 180 degrees. |
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ADD |
ADD is an additional strength for your lens for reading or upclose work. If you need reading, intermediate, bifocal or multifocal, or progressive lenses, this should be listed in your prescription. |
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PD |
PD: This number indicates the distance from the center of one pupil to the center of the other, and is an important number for lens customization. If your prescription doesn't have your PD on it, don’t worry, we have a tutorial that teaches you how to measure your PD yourself. |
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Prism |
Prism: This is the amount of prismatic power, measured in prism diopters ("p.d." or a superscript triangle when written freehand), prescribed to compensate for eye alignment problems. |
Other questions
Q: What is a PD?
PD stands for Pupillary Distance, which is the measurement from the center of one pupil to the center of the other. Your PD is an important factor and tells you where you look through the lens of your glasses and should be as accurate as possible. For people with strong prescription, this is especially important. You can normally find your PD on your prescription. Generally speaking, the PD numbers for adults stays the same. The average PD range for adults is 57-72 mm and for kids is about 43-58 mm.
Q: I have dual PD, how can I enter it?
A dual PD would be provided with two numbers and would appear and is the measurement of each pupil center to the center of the bridge of the nose, in millimeters. Dual PD appears in the following format: "31.5/31.5". When placing the order, please click "Two PD numbers" to enter your dual PD.
Q: I have PLANO /PL under SPH on my prescription
If there is "Plano" or "PL" in the SPH section of an Rx, it means no nearsighted or farsighted correction is needed. Just leave it as a zero or Plano when entering the prescription on the order form on our website.
Q: I have SPHERE/SPH /S/DS under CYL on my prescription
If the optometrist wrote "DS" or "Sph" or "Spherical" in the Cylinder space, it indicates no correction and should be entered as 0 on the order form. This means that the eyeball is spherical and has no oblongedness, and consequently has no Cylinder or Axis values.
Q: I have BALANCE/BAL on my prescription
Balance indicates that the eye for which the designation is made, is not sighted, and that the same numbers should be entered in both eyes, in order to have the lenses matched in appearance and weight.
Q: I have PAL （progressive addition lens ）on my prescription.
PAL,the Progressive Adjusted Lens. Because of the limited reading area of a progressive lens design, the Add portion of a prescription is increased by a quarter of a diopter (typically) to compensate by increasing the size of the image. It does not change the size of that portion of the lens. If you have two ADD values in your prescription (ADD +2.00 and ADD +2.25 PAL), the ADD value +2.00 should be used for both eyes of bifocal while ADD value +2.25 should be used for both eyes of progressive.
Q: Can I use my contact lens prescription when ordering eyeglasses?
Unfortunately, contact lens and eyeglass prescriptions are different. The simple reason is because contact lenses sit directly on your eyes, while eyeglasses are held in front of your eyes. Though the prescriptions may appear similar, they will differ in strength and are not interchangeable. We cannot — and, for your safety, would not — use your contact lens prescription to make your glasses. And we would advise you to contact your eye doctor to get your eyeglasses prescription.
I have a prescription, how to read it for different uses
For progressive or bifocal glasses, the prescription can be read as:
For single vision distance use, the prescription can be read as:
To convert a multi-focal prescription with ADD values for single vision distance use, simply remove the ADD values. The correction for the astigmatism will not change, so the cylinder and axis will remain the same, regardless of the change in focal distance. Use the original distance PD listed in the prescription.
For single vision computer use, the prescription can be read as:
To convert a multi-focal prescription for single vision computer use, simply combine half of the Add number and the Spherical number (If the Add cannot be split evenly, such as ADD +2.25, both +1.25 and +1.00 can be used to convert the prescription). For example, if the Add were +2.25 and the OD-Sph was -0.50, the new OD-Sph for computer glasses would be +0.75; if the Sph were +0.25, the new Sph would be +1.50. Consequently, the Add will then become zero, the default. The correction for the astigmatism will not change, so the cylinder and axis will remain the same, regardless of the change in focal distance. Narrow the PD by 1-2 mm. If the PD of your basic prescription is 29.5/31.0, the PD for computer glasses would be 29.0/30.5 or 28.5/30.0
For single vision reading use, the prescription can be read as:
To convert a multi-focal prescription for single vision reading glasses, simply combine the Add number and the Spherical number. For example, if the Add were +2.25 and the OD-Sph was -0.50, the new OD-Sph for reading glasses would be +1.75; if the Sph were +0.25, the new Sph would be +2.50. Consequently, the Add will then become zero, the default. The correction for the astigmatism will not change, so the cylinder and axis will remain the same, regardless of the change in focal distance. Narrow the PD by 3mm. If the PD of your basic prescription is 29.5/31.0, the reading PD would be 28.0/29.5.
That's it about prescriptions.
For more information, check our help center. We hope this was informative and helpful!
