How to read your glasses prescription
Reading a prescription can be a little intimidating at first sight. Who wouldn't be when looking at a combination of numbers, abbreviations and symbols that looks like an indecipherable military code.
If you know what to look for, you can make sense of the numbers and abbreviations on your prescription chart.
Latin abbreviations
Eye doctors like to play it old school and are still using Latin Abbreviations most of the time. Left or Right? OD is short foroculus dexter, the Latin phrase for “right eye.” OS is short foroculus sinister, Latin for, as you have guessed it, “left eye.”
Note that some doctors have started to modernize their eye prescriptions by using RE (right eye) and LE (left eye) instead of OD and OS.
+ or - ?
A “+” sign means you are long-sighted, and a “-” sign means you are short-sighted. These numbers represent the diopters you will need for your lens. Nearsighted people have trouble seeing things that are far away. Farsighted people have trouble seeing things that are up close.
The SPH value (sphere) indicates wether you have nearsightedness or farsightedness.
The CYL value (cylinder) indicates Astigmatism. It indicates the lens power needed to correct it.
The AXI value (axis) describes the lens meridian that contains no cylinder power to correct astigmatism. CYL and AXI go by pair.
If an eyeglass prescription includes cylinder power, it also needs to include an axis value, which follows the cylinder power.
Pupillary Distance
The PD value (Pupillary Distance) measures the distance between your pupils, and ensures the centre of the lens is in the right place.
This measurement is usually not included in your prescription. You can always ask your eye doctor to give your PD. After you have placed an order and our team has reviewed your precription, we will also send you a link that can be used to measure your PD accurately.
