Medical variance means a driver has received one of the following from FMCSA that allows the driver to be issued a medical certificate:
(1) An exemption letter permitting operation of a commercial motor vehicle pursuant to part 381, subpart C, of this chapter or § 391.64 of this chapter;
(2) A skill performance evaluation certificate permitting operation of a commercial motor vehicle pursuant to § 391.49 of this chapter.
49 CFR § 390.5T
Unless specifically defined elsewhere, in this subchapter: