Got your contact lens prescription and not sure what you're looking at? You're in good company. Here's a quick, friendly guide to what each value means — straight from our team at Eyes At Narangba.
Glasses vs contact lens prescriptions — they're not the same. Even if you have a glasses prescription, you'll need a separate one for contact lenses. We'll sort this out for you during your contact lens fitting.
OD and OS if it looks like Latin, you are spot on.
OD stands for oculus dexter, meaning right eye.
OS stands for oculus sinister, meaning left eye.
You may also see OU, which means oculus uterque — both eyes.
A fun language twist here: dexter is the root behind the English word dexterous, which gives the right eye a rather flattering start. Meanwhile, sinister in Latin originally just meant left, but English later gave it a much darker personality. So somewhere along the line, the left eye got a branding problem it did not deserve.
Base Curve (BC) is the curvature of the back of the lens — it needs to match the shape of your eye for a comfortable fit.
Diameter (DIA) is the size of the lens in millimetres. Together with BC, it determines how the lens sits on your eye.
Power / Sphere (PWR or SPH) is your vision correction strength. Negative = short-sighted, positive = long-sighted.
Cylinder (CYL) and Axis only appear if you have astigmatism. CYL is the correction strength, and Axis is the direction. No CYL on your script? You're likely in spherical or multifocal lenses.
Add Power (ADD) shows up on multifocal prescriptions and helps with reading vision as we get a little older — nothing to worry about!
Brand / Lens Type — we stock CooperVision, Alcon, and Bausch + Lomb, and we'll always recommend what suits your eyes best.
Expiration Date — prescriptions are valid for one year. Keep up with your annual eye exam and we'll keep you seeing your best.
Still have questions? Pop in or give us a call — we're always happy to help. Serving Narangba and North Brisbane.
