I present for your admiration and study the c. 1518, Portrait of Pope Leo X (Leone dieci, Giovanni di Lorenzo de’ Medici) with Two Cardinals, by Raffaello Sanzio (Raphael).

This painting is one of Raffaello’s last works and one of the few he designed and painted himself in his last years (i.e. without help from Giulio Romano or Gianfrancesco Penni). An illuminated prayer book lies open on the table in front of Pope Leo. On the same table rests a finely carved bell. Both objects reveal the exquisite tastes of the Pope who was an active patron of the arts, and somewhat of a bon vivant The pommel on top of the Pope's chair evokes the symbolic abacus balls of the Medici family, while the illuminated Bible open on the table has been identified as the Hamilton Bible. As an ophthalmologist, I am fascinated by the ocular issues of the de’ Medici and the signs we see here. We know that the de’ Medici were a learned, bookish and myopic family. It is written that Pope Leo “read letters always close to his nose.” But we can go further than inferences. The Pope’s myopia can proven here by the lens that he is holding in his Left hand. You might quite logically think that what the Pope is holding is a magnifying lens. But it is not a magnifier. Look carefully at it and you will not see any enlargement of Leo’s thumb beneath it, which a magnifier would do. (See comments) In fact, the tip of the thumb is slightly smaller than it should be. Thus the lens cannot be a magnifying lens. So what is it? In fact, this handheld lens still exists. You can see it in the Museo di Galileo (formerly Museo Storia della Scienza di Firenze). The handheld lens has been measured at - 12 diopters (minus signs before diopter numbers mean myopia, plus signs mean hyperopia or presbyopia). So, this Pope was myopic, indeed highly myopic. The cardinal to the left of the painting is identified as Giulio di Giuliano de' Medici. He would become the future Pope Clement VII. The other cardinal is usually identified as Luigi de' Rossi, who was a maternal cousin to both Pope Leo X and Cardinal Giulio di Giuliano.