Cal. Bus. & Prof. Code § 3147

(a) Except as otherwise provided by Section 114, an expired optometrist license may be renewed at any time within three years after its expiration, and a retired license issued for less than three years may be reactivated to active status, by filing an application for renewal or reactivation on a form prescribed by the board, paying all accrued and unpaid renewal fees or reactivation fees determined by the board, paying any delinquency fees prescribed by the board, and submitting proof of completion of the required number of hours of continuing education for the last two years, as prescribed by the board pursuant to Section 3059. Renewal or reactivation to active status under this section shall be effective on the date on which all of those requirements are satisfied. If so renewed or reactivated to active status, the license shall continue as provided in Sections 3146 and 3147.5.