Treatment of Cross-eyed: For more treatment information about Cross-eyed, see treatment of Squint (Cross-eyed).
It can be used to indicate a smaller than average scale (microscopic scale), as opposed to prefixes mega and macro, which can be used to indicate a larger than average scale. Micro may refer to: 1  micro- (Âµ) a prefix in the SI and other systems of units denoting a factor of 10 â6 (one millionth). 2  MICRO Information Management System, an early set-theoretic database management system. 3  Micro programming language, a simple programming language used in teaching compiler construction techniques.
There is no difference - they both mean 'micrograms'. Âµ is the Greek letter micron, which is used as Âµg for micrograms; sometimes this is abbreviated as mcg instead. So 60mcg is one-fifth of 300Âµg, so you are well within the defined limit. (or 60Âµg is one-fifth of 300mcg - they mean the same thing)