Prescription Guide

How to read your prescription

OD and OS: OD is short for the Latin term for Right Eye: "oculus dexter", and OS comes from the Latin for Left eye "oculus sinister." So just remember OD is your RIGHT eye and OS is your LEFT eye. 

PWR: PWR refers to refractive power. Sometimes this may also be called SPH (sphere.) This is the amount of correction, measured in diopters (an optical unit of measurement,) that is needed to bring your vision to 20/20. If this number is preceded by a minus sign (-), then you are nearsighted (you have myopia.) If there is a plus sign (+) before the number, you are farsighted (you have hyperopia.) It is common to have a different prescription in each eye.

BC: Base Curve - this refers to the back curvature of the contact lens, measured in millimeters. This number is usually between 8 and 9. This number is important for the fit of your contacts because it will match up with the the curvature of your cornea. If your prescription does not include a base curve, it's most likely because the brand of your lenses only comes in one base curve.

DIA: Diameter - the distance across the surface of the contact lens, measured in millimeters. This number is usually between 14 and 15mm and determines where on your eye the contact lens will sit. If this measurement isn't correct the contact lens will be uncomfortable and may scratch your eye. If your prescription does not include a diameter it's most likely because the brand of your lenses only comes in one size.

For Toric Lenses

CYL: Cylinder value. Usually a number between -0.75 and -2.75, this is the amount of power needed to correct your astigmatism.

Axis: Expresses the orientation of the cylinder value on the lens. This number is displayed in degrees, between 0 and 180°.

For Bifocal or Multifocal Lenses

ADD: Add Power - the additional magnifying power in portions of the lens designed to help with seeing up close (in diopters for some brands, Low/Mid/High for others)

D and N:  Dominant and Non-dominant lens.  Used for certain types of multifocal contact lenses such as the CooperVision family.

A current and valid contact lens prescription is required to place an order. Please be aware that a contact lens prescription is different from a glasses prescription, so you cannot use one for the other.