"Also provide evidence that your research has made a major breakthrough. Such evidence may include journals written about your research and the impact your research has had on your field, and that you research methods have been adopted by other scientists to further your work. "
Pay attention to the quoted. Ask somebody who cited your publications to write a supportting letter and put down something like "his work has major impact in this field and greatly influences ourown reserach etc." EB1a is not as difficult as many people think. You have 15 papers, you have multiple memberships (ACS obviously is not counted by the vo), you need well writen supporting letters. List your minor awards, judging other's work, key role in the NIH project....
If no concrete evidence,use supporting letter. Carefully respond to the RFE. You'll make it!