How to read your glasses prescription?

If you intend to order glasses online, you will need to know how to read your eye doctor's pres cription. Regardless where you come from, the expressions used in the prescription should be more or less the same. So let's learn how to read them! First you need to know the basic expressions used in prescriptions.

OD vs. OS Eye

OD is short for the Latin term oculus dexter which means right eye. OS is an abbreviation of the Latin oculus sinister which means left eye. You'll often see this terms on eyeglass prescriptions.

Sphere, Cylinder and Axis

The sphere (SPH) on your prescription indicates the lens power you need to see clearly. A minus (-) symbol next to this number means you're nearsighted, and a plus (+) symbol means the prescription is meant to correct farsightedness. The cylinder (CYL) number indicates the lens power needed to correct astigmatism. If this column is blank, it means you don't have an astigmatism. An axis number will also be included if you have an astigmatism. This number shows the angle of the lens that shouldn't feature a cylinder power to correct your astigmatism. A multifocal prescription will include an ADD value, sometimes marked as NV. This indicates the required strength for the near prescription in your lens. PD stands for pupillary distance, which is the distance between the centres of the pupils of your eyes. So now you know the basic terminology. Let's see how those parameters look on the prescription.

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Choosing the right lens type on your online order

So now you know what the values on your prescription mean and how to read them. The next step is to know where to put those values when making your order on our website. First you have to choose the type of lenses you need.

If you have (+) in front of the ‚sphere‘ values, then you are farsighted and need glasses for reading. If this value has (-) in front of it, you are nearsighted and need glasses for distance vision. Another option are multifocal lenses, which you need in case you are both (nearsighted and farsighted). Also your prescription will contain the value for addition in this case.
The last option you have on our website in to choose glasses with blue light protection, but this is an option for individuals without diopter.

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How to fill in the prescription values?

When making an order on our website, you will find the values for right and left eye one below another. The word ‚Power‘ equals the word ‚Sphere‘ on your prescription, and the other values should be named identically, so you will not have problems finding them. Also their order is the same as on your prescription. What you should be careful about is the PD (pupillary distance) value. Sometimes you get only one PD value on your prescription. In this case you have to divide the number with 2 to get the PD for both eyes.
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If you don't have this value on your prescription, you can easily measure it on our website by clicking the button ‚Measure PD online‘. If you need multifocal lenses, you will get an additional column with ‚Additiion‘ in the parameters section.

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Congratulations! You have learnt how to read your prescription and received all the necessary information to order your glasses online. If you'll have any additional questions, we'll be glad if you write to info@crulle.com.