Deciphering Your Prescription

Now you come to the most important part in making sure your glasses are perfect, the Prescription. This enables the Lab to customise each pair of glasses for every customer. You are not alone if you feel a little nonplussed – like everything else it is easy when you know what it means, if you don’t it feels daunting, so we are here to help step by step.

Please note that having read through the ‘Help Notes’ if you are not happy deciphering your prescription, you can fax it or scan and email or simply post a copy.

The layout can vary slightly but could look similar to our samples below:

First of all you will have SPH or Sphere which indicates the strength of your prescription in 0.25 increases. The measurement will be preceded by a + or -, in front or above the measurement, for example + 1.25 or -1.25. It is very important to select correctly the + or -, as this is the most common mistake when entering a prescription and will effect your prescription considerably.

Sometimes the prescription will be written without the decimal point 125 instead of 1.25

Occasionally there is no measurement but a word for example Plano that you will select instead.

Although not common, the sphere in one eye can be preceded with plus (+) while in the other eye it is preceded by minus (-).

Cyl or Cylinder is the next required figure and will be on the prescription if you have something known as‘astigmatism’. Again be careful to correctly put either plus or minus. The measurement value can be different but the plus or minus, should be the same for both eyes, unlike the Sphere that could be a plus in one eye and a minus in the other, the Cylinder is either plus for both eyes or minus for both eyes in 99% of cases.

Sometimes a prescription will show ‘DS’ in this column and simply means you do not have an astigmatism.

Axis – If you have a Cylinder value on your prescription you will have an Axis value too, and can be 0-180.

You may only have a cylinder or axis value for one eye and not the other, or sometimes there isn’t a value for either eye.

Add or Near Addition is the amount to add to the Sphere for reading and /or computer work. Sometimes it is shown as a completely separate line on your prescription but it is important to indicate if you require your glasses for reading or computer work. Mostly, although not always, the same addition is added for both eyes.

Pupillary Distance (PD) This is the distance between the patient’s eyes and is not always included on the prescription. It is always advisable to ask the Optician to state the PD on the prescription, although an average can be taken if necessary.

Prisms, usually indicates a patient may have a slight squint or lazy eye and any information relating to Prisms should be entered in the extra information box.