; or (2) if— (A) the veteran maintains substantially gainful employment; and (B) the Secretary, considering the totality of circumstances (including total household medical expenses and the cost of living in the area in which the veteran resides), determines that such assignation is appropriate. (c) Prohibition on the consideration of certain factors In making any determination under subsection (a) or (b), the Secretary may not consider the following: (1) The age of a veteran. (2) The eligibility of a veteran for any retirement benefit, including any benefit under title II of the Social Security Act ( 42 U.S.C. 401 et seq.). (d) Definitions In this section: (1) The term marginal employment means employment for which the earned annual income is less than 100 percent of the official poverty threshold for an individual established by the United States Census Bureau. (2) The term substantially gainful employment means employment for which the earned annual income equals or exceeds 100 percent of the official poverty threshold for an individual established by the United States Census Bureau. . (b) Clerical amendment The table of sections at the beginning of chapter 11 of title 38, United States Code, is amended by adding after the item relating to section 1163 the following: 1164. Determination of total disability by reason of unemployability. . (c) Regulations Not later than 180 days after the effective date of this Act, the Secretary of Veterans Affairs shall prescribe such regulations as may be necessary to carry out this section.