California Code, Business and Professions Code - BPC § 3109

Directly or indirectly accepting employment to practice optometry from any person not having a valid, unrevoked license as an optometrist or from any company or corporation constitutes unprofessional conduct.  Except as provided in this chapter, no optometrist may, singly or jointly with others, be incorporated or become incorporated when the purpose or a purpose of the corporation is to practice optometry or to conduct the practice of optometry.

The terms “accepting employment to practice optometry” as used in this section shall not be construed so as to prevent a licensed optometrist from practicing optometry upon an individual patient.

Notwithstanding the provisions of this section or the provisions of any other law, a licensed optometrist may be employed to practice optometry by a physician and surgeon who holds a license under this division or by a health care service plan pursuant to the provisions of Chapter 2.2 (commencing with Section 1340) of Division 2 of the Health and Safety Code.