Convert from furlong [international] to gnat's eye

Unit Definition (furlong [international])
The furlong is a traditional unit of distance. Long before the Norman Conquest in 1066, Saxon farmers in England were measuring distance in rods and furlongs and areas in acres. The word "furlong", from the Old English fuhrlang, means "the length of a furrow"; it represents the distance a team of oxen could plow without needing a rest. A furlong equals 40 rods, which is exactly 10 chains, 220 yards, 660 feet, or 1/8 mile. One furlong is exactly 201.168 meters, so a 200-meter dash covers a distance very close to a furlong. The length of horse races is often stated in furlongs.

Unit Definition (gnat's eye)
The gnat's eye is an idiomatic "unit" of distance; it's common to hear that something is "as small as a gnat's eye". In fact, the eyes of typical gnats tend to have diameters similar in size to a hair's breadth: roughly 100-150 micrometers (0.10-0.15 millimeters).