Left Eye Sphere (SPH)
Sphere or Power – SPH or PWR – This is the main strength of your glasses prescription, and is written in +/-0.25 increments. There is sometimes a DS after this number. This just means Dioptres.
Plano – PL – ∞: This means Zero power. If you have this in the sphere field, then enter it as Plano or ∞ in the drop down menu.
Balance – This means there is no functional power in this eye. Usually due to poor vision in this eye. The Balance lens is merely for cosmetic purposes to give a “balanced” look on the lens thicknesses.
Left Prism Distance
If your eyes have a tendency to not be aligned, then you may require prism in your glasses. This will help align the images so they are fused together by the brain, resulting in comfortable 3-D vision or Stereopsis.
Left Prism Near
A prism is used when both eyes are not properly aligned and they need a prism to re-align them. The Base is the rotation of the prism. These fields are rarely used.
There are two separate parts to a Prism correction. The first part is the diopter strength (e.g. 2.0) and the second is the direction (e.g. BU). There are four different directions. Base-Up (BU), Base-Down (BD), Base-In (BI), and Base-Out (BO).
Right Base Distance
This is the direction the aligning prism needs to be set at. The direction will be one of either UP, DOWN, IN, OUT. The two eyes can have prism that is opposite in direction e.g, Right eye UP and left eye DOWN. This is perfectly fine. Just enter what you see on your prescription. If you are unsure, ask our qualified Opticians.
Right Base Near
A prism is used when both eyes are not properly aligned and they need a prism to re-align them. The Base is the rotation of the prism. These fields are rarely used.
There are two separate parts to a Prism correction. The first part is the diopter strength (e.g. 2.0) and the second is the direction (e.g. BU). There are four different directions. Base-Up (BU), Base-Down (BD), Base-In (BI), and Base-Out (BO).
Right Eye Axis (AXI)
The axis of the Cylinder lens for your astigmatism, will sit at a particular angle from 0-180 degrees. If you do not have an astigmatism, then simply put “0” or “zero” in this field.
Right Eye Cylinder (CYL)
Cylinder – CYL – This indicates the amount of astigmatism, and is written in +/-0.25 increments. If this field is blank in your prescription, then this means you do not have an astigmatism. Please enter this value in the drop down box as Plano.
Don’t forget to add the + or – sign in the drop down menu. Just enter whatever you see in the prescription. If you are unsure, or if one eye is + and the other is -, then contact us. We are always glad to help.
Astigmatism just means your eye is rugby ball shaped. You’ve been told this many times by Opticians, but what does it mean? It is simply that you need two lenses (placed perpendicular to each other) to correct your vision in each eye, rather than just the one.
Right Eye Near addition (ADD)
ADD – This is a value that is commonly used for bifocal or progressive lenses, as well as reading glasses. It indicates how much power gets added to the distance Rx to create the reading-only Rx; or as it applies to the glasses you order, it determines the correction strength for the bottom half of your bifocals progressive lenses. It is written in increments of 0.25 ranging between +0.25 and +3.50.
Right Eye Sphere (SPH)
Sphere or Power – SPH or PWR – This is the main strength of your glasses prescription, and is written in +/-0.25 increments. There is sometimes a DS after this number. This just means Dioptres.
Plano – PL – ∞: This means Zero power. If you have this in the sphere field, then enter it as Plano or ∞ in the drop down menu.
Balance – This means there is no functional power in this eye. Usually due to poor vision in this eye. The Balance lens is merely for cosmetic purposes to give a “balanced” look on the lens thicknesses.
Right Prism Distance
If your eyes have a tendency to not be aligned, then you may require prism in your glasses. This will help align the images so they are fused together by the brain, resulting in comfortable 3-D vision or Stereopsis.
Right Prism Near
A prism is used when both eyes are not properly aligned and they need a prism to re-align them. The Base is the rotation of the prism. These fields are rarely used.
There are two separate parts to a Prism correction. The first part is the diopter strength (e.g. 2.0) and the second is the direction (e.g. BU). There are four different directions. Base-Up (BU), Base-Down (BD), Base-In (BI), and Base-Out (BO).
What’s your Pupillary Distance?
