To order you new glasses, you will be asked to enter your corrections which figures on your prescription. That can seem like a daunting task but let's have a look at it together.

Before reading, remember that if this all seems too complicated, scan or mail your prescription to us and we'll do all the work for you. Now, read on!

First of all, there are 3 common prescription types:

Horizontal

Vertical

NHS

Let's define the different sections:

• RIGHT or O.D: right eye
• LEFT or O.S: left eye
• SPH or Sphere: every prescription has a positive OR negative number there representing your degree of correction needed, in 0.25 increments
• CYL or Cylinder: this sign defines your degree of astigmatism. It can be zero or a positive OR negative number. Here again, being positive or negative is very important.
• AXIS: If you have a number in the cylinder reading then you must have a number in the axis reading that goes from 0 to 180.
• Add or Addition: this is the value to add to the sphere to allow you to read or look at your computer. This value is used to make progressive lenses.

In any case, if a value space is blank, it means that this value is equal to zero.

Special markings:

Sometimes, you will find signs written by your doctor that you don't understand, here they are:

• Infinity (sideways 8): that will mean zero.
• Balance: this is written when one of your eyes has very little or no vision at all. Your doctor then is concerned in you having balanced lenses, in weight and thickness, even though your corrections are very different from one eye to the other.
• 3/36: useful for opticians, don't worry about this sign.
• PD or Pupillary Distance: this represents the distance between your two pupils. This value is used to place the most efficient part of the lens in front of your pupils. This has to be measured by a professional as to ensure maximum accuracy. More details on Pupillary Distance