Right Eye (O.D.)
OD stands for "Oculus Dexter," Latin for "right eye". This will always be listed first on your prescription.
Left Eye (O.S.)
OS stands for "Oculus Sinister," Latin for "left eye". This will always be listed second on your prescription.
Power / Sphere / D
This is the strength of your prescription. It is sometimes abbreviated to PWR or SPH. Before the number there is a minus or plus symbol before, depending on if you're nearsighted (-) or farsighted (+).
Base Curve (BC)
This number measures the curve of the lens and is usually between 8 and 10. The base curve of your lens determines how it will sit on your eye.
This is the width of the lens in millimeters. Usually this is a number between 13.5 and 15 mm.
This is only for people who have astigmatism, when one part of the eye needs more correction than the rest of the eye. This is different than the measurement for Power.
The axis measurement is only for people who have astigmatism. The axis (between 0 and 180) indicates the location of the cylinder within the lens.
Add Power (ADD)
This is only for individuals who wear multifocal contacts. It is usually written as a plus (+) sign followed by a number or, sometimes with a description like "low" or "high."
Every contact lens prescription is brand specific which indicates which type of contacts you need to buy. Every brand is made with different materials and water content.
Depending on your state, your contact lens prescription is valid for one or two years.