Understanding your prescription
To place an order for glasses, you will need a valid and current spectacle prescription. A contact lens prescription cannot be used to make glasses. Use the information below to work out what information you need to provide when ordering your glasses.
There are some prescriptions that we are unable to make in the glasses we supply. This is due to a number of factors. Some prescriptions require the customer to be measured by their eye care professional for things like the distance from the front of the eye to the surface of the lenses. Obviously when buying glasses online this is impossible to know, therefore if your prescription has more values than what we ask for, or they don’t seem to be asked for at all… it probably means you will be unable to purchase glasses from our site. If you wish to be doubly sure, you can email us a copy of your prescription and we will verify it for you. Send it to firstname.lastname@example.org
This is to help us know what you will be using your glasses for which can sometimes affect your prescription. We’ve tried to make it easy by describing it as reading for near vision and driving for distance vision. If you wear glasses all the time, or have bifocals or progressives, select reading and driving.
This is the type of lenses you require. For bifocal or progressive lenses, there will always be an ADD Sphere. This is usually the same for each eye but not always. For single vision use, select Not Applicable for the ADD Sphere. You must know what type of lenses you have been prescribed for. We are unable to assist you with this. You will need to consult your eye care professional if you require clarification of this.
Pupillary Distance or PD
This is the distance between your eyes, measured from the centre of one pupil to the centre of the other. It is the measurement in millimeters. For a pair of glasses to give you the best vision correction possible, the lenses need to be made to match this distance between your eyes, so that the centre of each lens aligns with the centre of your pupils. Your eye care professional should give you your PD as part of the prescription however some do not. You should always ask for this to be included as part of your eye check.
Your PD is very important so never try to guess your PD value. While an optometrist's PD value is always recommended; you can get this measurement yourself. Have a friend or family member measure it by holding a ruler just below your eyes and measure the distance in mm from centre to centre.
If a pair of frames cannot accept your PD, you can't simply change your PD simply to make it work because you will not be able to see through a lens produced with an incorrect PD. The correct PD is particularly important for a multi-focal lens (bifocal and progressive), as there are multiple viewing fields which are adjusted on the basis of the PD supplied.
The PD is often left off the prescription, although it’s usually recorded in your file. Having your PD empowers you to purchase glasses from any supplier, not just with the place where you got your exam. It is your right to have your PD - you paid for it with your prescription.
A PD may be indicated in a variety of ways. You will often be given a single number – this should be your distance vision PD and is what you will need for purchasing glasses on our site. Most adults have a PD between 53 and 70, and children will be between 41 and 55. You might be given two numbers such as 63/60. This would mean that you use 63 as your PD for distance vision. The smaller number would be used only when converting the prescription to single vision reading glasses. You may be given fractional PD measurements, right side and left side, and split PDs may be written as 30.5/31, for example. Simply add the two numbers together to get your distance vision PD.
If your PD falls outside the range we offer in our drop down menu, we will be unable to supply glasses for you.
Left and Right Sphere (SPH)
This is the main power measurement for your lenses. It is always a + (plus) or – (minus) value eg: -1.75 Select this from the drop down menu. If your sphere measurements are greater than what is displayed in the drop down options, we will be unable to supply glasses for you. They are sometimes written as OD and OS. OD simply means Right eye and OS means Left eye. Rarely used is OU which means both eyes.
Cylinder and Axis
These two measurements will be included if you have a condition called astigmatism. This is an irregularity in the shape of the eye, which causes vision distortion. It is quite normal to have some correction for this. Cylinder will be a number that is preceded by either a + (plus) or – (minus) value eg: -1.75 Very similar to the Sphere. The Axis will be recorded as a degree reading between 1 and 180 degrees.
Near Addition (ADD)
Required for Progressive or bifocal lenses only! - not single vision This is the reading portion of a lens in a multi-focal prescription. This number indicates the strength of the part of the lens that will be used for reading. It is usually same positive (+) number for both eyes, and it may be written only once on your prescription. The ADD can be found in the ADD section of the prescription, and is often annotated "NV," as in "near vision." It may also be written as a large, positive number, across both the OD and OS lines of your prescription.
Commom Layouts of prescriptions:
Lens tints or Anti-reflective coating
Lens tinting or anti-reflection coating can be added to your lenses as an option. They both cost an extra $15.95 on top of your frames and lenses price.
Prism is a value that is used for people that have a slight squint or a lazy eye. If you have prism values on your prescription, we will be unable to supply glasses to you at this stage.
Intermediate, Int or Int ADD
This is an intermediate sphere value between your main sphere and the ADD or Near addition value. We currently do not supply glasses with an Int value. You can still order glasses however, but you will need to leave this value out.
This is sometimes entered when there is little or no vision in one eye. It is used to ensure the lens that is used for that eye matches the weight and thickness of the other lens for comfort and cosmetic purposes.
Markings eg: 6/24
These are indicators of your current level of vision, but are not used for glasses.