For some reason, I was reminded of this joke today. No idea why, but it still makes me laugh. It's a Spider Robinson, of course...
Harry Lime is best remembered by his portrayal by Orson Wells in "The Third Man." During World War II, a British agent actually was known by the code name, Harry Lime. This Harry Lime was very near-sighted and wore thick glasses. His assignment behind Nazi lines as a German Officer would have been impossible if the Americans had not invented a new form
of lens for the myopic. These "contact lenses" were undergoing clinical trials at the Walter Reed Naval Hospital in Bethesda, Maryland.
Arrangements were made to transport Harry secretly to Bethesda by submarine to be fitted with contact lenses. Harry was a womanizer and had an old flame in nearby Washington. Afraid that Harry would use this opportunity to take an unauthorized vacation, it was decided to give him very explicit orders. Therefore, just before leaving for the ship, he was called to his control's office where he was given this direct order
..."You are to go directly from the sub, Lime, to the Reed oculist."