Filling the prescription details is pretty simple providing you have your glasses prescription to hand.
Sph value denotes Sphere and refers to the spherical part of your lens. If the Sph number has a + before it then it means you are long sighted. If it has a – before it then it means you are short sighted.
Cyl value denotes cylinder and refers to the cylindrical part of your prescription. It mentions the degree of astigmatism and has a + or – added before it.
Axis mentions the meridian of astigmatism and generally ranges between 0 to 180.
Near Add is an additional power required for reading or seeing things very close.
PD denotes Pupillary Distance and represents the distance between the mid points of the two pupils between your eyes.
- Read the values from your prescription and fill in the appropriate ones using the drop down menus placed next to the respective specifications.
- Do not forget to select the minus (-) signs from the menu, if it is mentioned in your prescription.
- If the Sph of the left eye is +0.75, then select 0.75 from a dropdown menu that says Sph.
- If the Cyl of the right eye is -0.75, then select -0.75 from a dropdown menu that says Cyl.
- Select the right Axis value number for each eye as per your glasses prescription.
- Add values are usually given if you need vari-focal, bi-focal or reading lenses. ADD is usually the same for both the eyes. Some optometrists mention the ADD value for both eyes while some write only one.
Your optometrist should provide your PD value during the eye test. Please request you PD measurement from your Optometrist if you do not have it. In case you do not get this value, we will fill in the average PD value for the UK population. The PD is the inter papillary distance or the distance between the mid points of the two pupils when looking at a distance straight ahead of you.
In fact it is possible to measure your own PD with some one’s help using the following method.
You need a ruler and a mirror to measure your PD using this method.
- Firstly, look straight into the mirror placed in front of you (at your eye level). Hold the ruler against the forehead where the bridge of the nose meets. This makes ruler markings on the forehead.
- Keeping your left eye closed and read the zero marking of the ruler with your right eye.
- Then keep your right eye closed and repeat the same with your left eye.
- Take care to keep the ruler in place.
- Repeat this process at least a couple of times to get concurrent readings.
Most people have a PD measurement in the range: 55mm and 70 mm.
Of course it's easier to obtain this information from your prescription or from your Optician to ensure exact measurements.
Now that you have filled in all your prescription details, you can proceed further and checkout of the page or continue shopping.