Subject to subsection (b) of this section, the Commissioner of Social Security may make such administrative and other arrangements (including arrangements for the determination of blindness and disability under section
1382c
(a)(2) and (3) of this title in the same manner and subject to the same conditions as provided with respect to disability determinations under section
421 of this title) as may be necessary or appropriate to carry out the Commissioner’s functions under this subchapter.