Any judge of the supreme, district or municipal court, including a district associate judge, or a judge of the court of appeals, who shall have served as a judge of one or more of such courts for a period of four years in the aggregate and who believes the judge has become permanently incapacitated, physically or mentally, to perform the duties of the judge’s office may personally or by the judge’s next friend or guardian file with the court administrator a written application for retirement. The application shall be filed in duplicate and accompanied by an affidavit as to the duration and particulars of the judge’s service and the nature of the judge’s incapacity. The court administrator shall forthwith transmit one copy of the application and affidavit to the chief justice who shall request the attorney general in writing to cause an investigation to be made relative to the claimed incapacity and report back the results thereof in writing. If the chief justice finds from the report of the attorney general that the applicant is permanently incapacitated, physically or mentally, to perform the duties of the applicant’s office the chief justice shall by endorsement thereon declare the applicant retired, and the office vacant, and shall file the report in the office of the court administrator, and a copy in the office of the secretary of state. From the date of such filing the applicant shall be deemed retired from the applicant’s office and entitled to the benefits of this article to the same extent as if the applicant had retired under the provisions of section 602.9106.