From "reading stones" to contact lenses, this Advent calendar contains stories from the field of ophthalmology. With the discovery of the optical effects of transparent "reading stones" by Alhazenon the 11th century, came a fundamental revolution. Elderly, presbyopic humans were now able to read again. So instead of candy when you open one of 31 doors on the calendar, you´ll lopen to a 2-page brief from a world both wonderful and occasionally weird.weiterlesen