The Office of Management and Budget (OMB), which is part of the White House, has to approve any new regulations that Social Security and other agencies want to publish in the Federal Register. On March 5, OMB approved a final version of new visual disorder listings for Social Security. Once OMB approves new regulations for Social Security, they ordinarily appear in the Federal Register in less than a week. However, that's not required. An agency can decide not to publish regulations even after obtaining OMB approval. Former Commissioner Michael Astrue decided not to publish proposed new mental impairment listings that were approved not long before Barack Obama was elected President.
It's now been two weeks since OMB approved these regulations. The proposal was noncontroversial when it was originally published for comments. I wouldn't read much into this delay but it is getting noticeable.