Ohio Rev. Code § 4732.20: Practice of medicine prohibited.

This chapter does not authorize any person to engage in any of the acts which are regarded as practicing medicine under section 4731.34 of the Revised Code. In order to make provision for the diagnosis and treatment of medical problems, a licensed psychologist engaging in psychological psychotherapy with clients shall maintain a consultative relationship with a physician licensed to practice medicine by this state. The practice of psychology, the practice of independent school psychology, the practice of school psychology, or the use of psychological procedures does not include the diagnosis or correction of optical defects or conditions through the utilization of optical principles, including optical devices or orthoptics.