Extrema 1-day (30)

Here is the information that a prescription from your eye care professional should contain:

(This information can also be found of the contact lens box, see below).

Explanation:

» OS
= Your left eye. In this column/section, you find the parameters for your left eye.

» OD
= Your right eye. In this column/section, you find the parameters for your right eye.

» OU
= Both eyes (your eyes have exactly the same parameter)

» PWR (or Rx, D, F, SPH or BVP)
= Power / Sphere  (a number between -25 and +25). This is the strenght of your contact lens (e.g., -1.50, -1,75, +1.00, +2.50, etc.).
If you are nearsighted (can see only near objects well) then order minus powers, if you are farsighted (can see distant objects) please order plus powers.

» BC (or BOZR)
= Base Curve  (a number between 8.0 and 10.0). This is the inside curve of your contact lens (e.g.,8.0, 8.1, 8.2, etc.).
Many contact lenses come in only one base curve, many others in only two base curves, some come in multiple base curves so care must be taken when ordering. If your box or prescription says MEDIAN instead of a number for base curve choose 8.5, 8.6 or 8.7 only.

» DIA (or TD)
= Diameter (a number between 13.0 and 15.0). This is the diameter (width/size) of your contact lens (e.g.,13.8,14.0,14.2, etc.)
Many disposable contact lenses are available in only one diameter; if you see only one choice for diameter you may confidently select it.

» ADD
= Add power. This is the additional correction for bi-/multi- focal contact lenses. It is the amount of additional (+) power needed for correction of presbyopia (added multifocal power for near distance). The ADD value is only used for multifocal lenses.
Multifocal (bifocal) lenses can include a numeric "Add Power" (ie, +2.00 or +1.50 etc.) for magnification, or the lenses / prescription simply says "Low" or "High" power magnification.

» BRAND
= The brand name given to the contact lens - for example "Soflens" or "Acuvue 2".

For astigmatic patients, there is also the following parameters:
» CYL (or ZYL) = Cylinder (a number between -4.00 and +4.00). This is the strenght of your astigmatism (e.g.,-0.75, -1.00, -1.25, etc.)

» Axis (or Axes, AX or X) = A number between 0 and 180 (note that 0 = the same as 180). This is the orientation of your astigmatism (e.g., 180,160, 90, etc.)

Cylinder and Axis are usually separated by × and read as "times" (example: -0.75x160).
The lenses for astigmatism are the toric lenses in our menu.

A contact lens prescription is not the same as an eyeglass prescription.
The power of the contact lenses is generally not the same power as in your eyeglass prescription. This is because the contact lens is located on the surface of your eye, while your eyeglasses are located about 10-14 mm in front of your eye.

In addition to lens power, a contact lens prescription contains other information related to the size of the lens.