Following an eye exam, you’ll be given a prescription with abbreviations such as OD, OS, SPH, and CYL. Your provider may know what these mean — but do you? We explain what OD, OS, and the ...

Dr. Colby answers the question: 'Are Different Contact, Glasses Rx OK?' Aug. 24, 2009— -- Question: Is it okay to wear one prescription of contact lenses and a different, older prescription ...