(1) A member who has 8 or more years of credited service and who is physically or mentally totally disabled to perform his or her duties is entitled to retire due to disability as provided in this section. A member who has 8 or more years of credited service agrees to submit himself or herself to a medical examination by or under the direction of the medical adviser as required by the retirement board under this subsection. Upon written application for retirement due to disability filed with the retirement system by the member, the chairperson of the judicial tenure commission, or the chief justice of the supreme court, the retirement board shall request that the member submit to a medical examination by or under the direction of the medical adviser.

    (2) The medical adviser, after a medical examination of the member, shall determine if the member is physically or mentally totally disabled to perform his or her duties, if the incapacity is likely to be permanent, and if the member should be retired due to disability. The medical adviser shall file a written report of the medical adviser’s findings and shall certify his or her determination to the retirement system. The retirement board shall notify the member of the medical adviser’s determination under this subsection by registered mail sent to his or her last known residence address.

    (3) The member, before the expiration of 30 days after the date of the notice by the retirement board under subsection (2), may file a written notice to appeal the medical adviser’s determination with the retirement system. If a notice to appeal the medical adviser’s determination is filed by the member under this subsection, the retirement board shall establish a medical committee to hear the appeal. The medical committee consists of a physician appointed by the retirement board, a physician appointed by the member, and a physician appointed by the first 2 physicians appointed under this subsection. The medical committee, after a medical examination of the member, shall determine if the member is physically or mentally totally disabled to perform his or her duties, if the incapacity is likely to be permanent, and if the member should be retired due to disability. The medical committee shall file a written report of the medical committee’s findings and shall certify the medical committee’s determination to the retirement system. The retirement board shall notify the member of the medical committee’s determination under this subsection by registered mail sent to his or her last known residence address. The determination by a majority of the medical committee is binding upon the retirement system and the member.

    (4) A member who refuses to submit to a medical examination required under this section and the refusal continues for 90 days or more; or a member for whom it is determined under this section that he or she should retire due to disability and who fails to retire before the expiration of 60 days after the retirement board sends notice of that determination under subsection (2) or (3), whichever is later, forfeits for himself or herself and his or her heirs and beneficiaries all rights in and to retirement benefits under this act except the refund of accumulated contributions.

    (5) Upon determination under this section that a member who has 8 or more years of credited service is physically or mentally totally disabled to perform his or her duties, the retirement board shall retire the member due to disability. Upon retirement due to disability under this section, the retirement system shall pay to the disability retirant a retirement allowance calculated pursuant to section 503. At the time of retirement under this section, the member may elect to be paid an optional retirement allowance under an optional form of payment provided in section 506 in lieu of the straight life retirement allowance under section 503.