Mo. Rev. Stat. § 537.170: Waiver of rights to damages by blind employee.

It shall hereafter be lawful for any blind person over the age of eighteen years to agree to and with his or her employer to waive his or her right to damages or compensation for any personal injury arising out of or in the course of his or her employment for which injury such blindness was the direct or contributory cause and any such agreement shall be valid and binding upon the parties thereto.