Cal. Bus. & Prof. Code § 3096

(a) A licensee may be ordered to undergo a professional competency examination if, after investigation and review by the Board of Optometry, there is reasonable cause to believe that the licensee is unable to practice optometry with reasonable skill and safety to patients. Reasonable cause shall be demonstrated by one or more of the following:
1. (1) A single incident of gross negligence.
2. (2) A pattern of inappropriate prescribing.
3. (3) An act of incompetence or negligence causing death or serious bodily injury.
4. (4) A pattern of substandard care.
(b) The results of a competency examination shall be admissible as direct evidence and may be considered relevant in any subsequent disciplinary or interim proceeding against the licensee taking the examination, and, assuming those results are determined to be relevant, shall be considered together with other relevant evidence in making a final determination.