Doctors of optometry (ODs) are the primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the visual system, the eye, and associated structures as well as identify related systemic conditions affecting the eye. Optometrists in the United States are licensed to prescribe medications to treat certain eye problems and diseases. The scope of medical care that can be provided by optometrists is determined by state law.