(a) A member may apply for a disability retirement annuity by:
(1) filing a written application for retirement with the board of trustees; or
(2) having an application filed with the board by the member's legal representative.
(b) In addition to an application for retirement, a member shall file with the board of trustees the results of a medical examination of the member.
(c) The board of trustees by rule may require the submission to it of additional information about a disability. The retirement system shall prescribe forms for the information required by this section.