Section 16. There shall be a board of registration in optometry, in the following sections called the board, consisting of five members, citizens of the commonwealth to be appointed by the governor, four of whom shall have been engaged in the practice of optometry as defined in section sixty-six of chapter one hundred and twelve for the five years next preceding their appointment, and one of whom shall be a representative of the public, subject to the provisions of section nine B. One member shall annually, in September, be appointed by the governor for a term of five years. No member of the board shall be a stockholder of any school of optometry, a member of the faculty or on the board of trustees thereof, or financially interested in a manufacturing or wholesale optical business. No registered optometrist shall be appointed or reappointed to the board unless he is certified for use of diagnostic pharmaceutical agents under the provisions of section sixty-six A of said chapter one hundred and twelve.