The amount of assistance which any needy blind person shall receive shall be determined by the county department with due regard to the resources and necessary expenditures of the individual and the conditions existing in each case and in accordance with the rules and regulations made by the state department, and shall be only sufficient, when added to all other income and support of the recipient, to provide such persons with a reasonable subsistence compatible with decency and health. In making such determination the state department shall disregard the earned income specified by the federal Social Security Act, as amended, and may disregard any other income of the recipient as specified in the federal Social Security Act, as amended.