N.D. Cent. Code § 43-13-31

A person may not discriminate between licensed practitioners of optometry and physicians, or interfere with any individual's right to free choice of ocular practitioner, with respect to the providing of professional services within the scope of section 43-13-01. If a health, accident or disability policy or insurance contract, or any other type of benefit or safety program specifically provides for the payment of optometric services within the scope of section 43-13-01, the payment must be made regardless of whether the service is performed by a physician or optometrist.