We explain what OD, OS, and the others mean so you can better understand your vision and its necessary corrections. Following an eye exam, ... Glasses are about 12 millimeters ...

Why It’s Crucial to Use Glasses with the Correct Optical Density Working with lasers can pose a major risk if the correct protective equipment isn’t used and the laser isn’t operated properly.

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 ...