Learn more about how to read your prescription. It really isn't very difficult if you know what the terms mean. Click on the link to Read and Understand your Prescription.
Sphere SPH:
This is the number by which your sight needs to be corrected. It will have a + or a – value. The numbers go upwards in steps of 0.25.
It is very important that these symbols (+ or -) are used correctly when adding your prescription details, as they are an indicator of long or short sightedness.
Cylinder CYL:
This is a number by which any astigmatism has to be corrected.
This also has + and – value and goes upwards in steps of 0.25.
Astigmatism:
It
is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina.
Axis:
it is used to define a direction along which there is some degree of rotational symmetry. This is the axis for which the correction for the Astigmatism needs to be set at. This will only have a number in it if you have a number in the CYL. The values for the Axis can be between 0 – 180.
Addition (NEAR) ADD:
This only applies if you use your glasses for reading purposes. This value is always +. Sometimes this is also referred to as NEAR.
If you require reading glasses please include the ADD or NEAR.
If you require Distance or Driving glasses then we do not need the ADD number.
If you use your glasses for computer work then you may have an Intermediate value. Please put this value into you prescription.
Pupillary Distance (PD):
The pupillary distance is a measure of the distance between the pupils of your two eyes. It is the distance from one eye to the other. The Pupillary Distance (PD) is usually written as one value (60mm) but sometimes written as 34/33 if one eye is slightly further away from the centre of the nose than the other.
The PD measure is important if you want to get the best possible fit for your lenses, so that your glasses work at the optimum level. It is a fact that this measurement is sometimes left off your prescription by the high street opticians because they want you to buy your glasses from them. Therefore please ask them to supply this number.
If for any reason you are unable to get the PD number, please don't worry as we are still able to make your glasses. Advancespex.com will simply fit an average PD measurement which is based around knowledge of average numbers through the most up to date research. This will be a good fit for the majority of people. However if you feel that you need an accurate PD measure because of the shape of your face, then why not take the measure yourself. It may help to get a partner or friend to help you.
All you need is a ruler that can measure in millimeters (mm)
See example below
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