SPH, for Spherical, refers to the refractive correction in the prescription. Minus (-) are for near sightedness, and Plus (+) values are for far sightedness. If "PL" or "Plano" is written for the either SPH value on your prescription, you should select a value of 0.00.
OD-SPH is spherical correction for your RIGHT eye.
OS-SPH is spherical correction for your LEFT eye.
CYL, for Cylinder, refers to the strength of the correction for the astigmatism in the eye. It can be either positive or negative. If there is a CYL value on an eye, there must be an Axis value on that eye.
If "DS" or "SPH" or "spherical" is noted in the CYL space on your prescription, you have no astigmatism in that eye. In that case, enter 0.00 in both the CYL and Axis.
OD-CYL is cylinder correction for your right eye.
OS-CYL is cylinder correction for your left eye.
AXS, or Axis, refers to the angle of the correction for the astigmatism in the eye (if one exists) from 1 to 180. If there is an Axis value on an eye, there must be a CYL (Cylinder) value on that eye. If there is no Cylinder value or if the value is zero, the OD Axis value is entered as 0.00.
The Axis value is usually written as 3 digits, which means if your Axis value is 5, it is often written as 005. This Axis value is still 5, regardless of how it is displayed.
OD Axis is Axis correction for your right eye.
OS Axis is Axis correction for your left eye.
Pupillary Distance (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.
How to Measure PD?
A:PD is very important for accurately fitting your lenses to achieve vision acuity. Generally speaking, the average PD for adults is 55-70 mm and for kids is about 50-70 mm. A difference about 2-3 mm is allowable.
Checking with your doctor is recommended. You can also measure it this way.
Step 1:Stand with a friend facing you and place a millimeter ruler on the bridge of your nose. Keep the rule "0" measurement is exactly in line with the center of your left pupil. Hold the ruler straight.
Step 2: Let your friend read the measurement between the left pupil and the right pupil while you look straight ahead.
Step 3: For measuring a PD with high accuracy, please do it 3 times and take an average number of them as the final PD measurement.
For those requiring bifocal or progressive lenses, we strongly recommend you get this information from your optician to ensure the accuracy of your glasses.
You may also measure your PD in front of a mirror,here we show how to do it.