LONDON, UNITED KINGDOM - JANUARY 20: Sophie, Countess of Wessex examines the eye of Prince Edward, Earl of Wessex using a Portable Eye Examination Kit, (PEEK) which turns a smart phone into a comprehensive eye exam tool, giving high resolution images of the eye at minimal cost, during a visit to the London School of Hygiene and Tropical Medicine, a centre for research and postgraduate education in public and global health in London, on January 20, 2015, in London, United Kingdom. (Kirsty Wigglesworth - WPA Pool/Getty Images)
