Wondering how to read your contact lens prescription you got at the eye doctor? Dr. Nagori is here to explain how to make sense of it and what those numbers and acronyms on your prescription mean. On the far left of your prescription, you may see OD, meaning right eye, and OS, meaning left eye. You’ll also see a few measurements under the acronyms Sph, BC, and DIA. Sph is your sphere power, or the main measurement of your prescription. BC and DIA stand for base curve and diameter, which has to d