(a) After obtaining a minimum of four years of creditable service, any member who becomes totally and permanently disabled to the extent that he or she is unable to perform the duties of his or her office shall be entitled to receive a disability retirement benefit which shall be one-half of the maximum retirement benefits provided by Code Section 47-23-102 for 16 years of service, unless the member would otherwise qualify for a greater benefit under Code Section 47-23-102 or 47-23-103, in which event the Code section providing the highest benefit would apply.

(b) After obtaining a minimum of ten years of actual service, any member who becomes totally and permanently disabled to the extent that he or she is unable to perform the duties of his or her office shall be entitled to receive a disability retirement benefit which shall be two-thirds of the maximum retirement benefits provided by Code Section 47-23-102.

(c) The disability of any member applying for disability retirement benefits shall be determined by the board in the same manner and under the same procedure as disability of state employees is determined in accordance with the applicable provisions of the Employees' Retirement System of Georgia. Disability retirement benefits shall become effective on the first day of the month following the month the member resigns as a result of the disability.