American astrophysicist and author and science communicator Neil deGrasse Tyson once tweeted, “If shrunk to a few inches across, Earth would feel as smooth as a billiard-hall cue ball.” Actually, the surface of an ophthalmic lens has something we have spread across the entire surface of our planet. That something is the system of latitude and longitude, a concept which works well over both curved and flat surfaces. We are consistent in using longitudes (e.g., interpupillary distance), but latitude (e.g., needed for MRP location) is a coordinate too often overlooked. Learn more about lens geography in this Rxpertise feature by Palmer Cook, OD, from 20/20 Magazine. Read More.