King-Devick Test® (K-D Test®) All rights reserved. Copyrighted. ©1983, 2010-2017, Patents-Pending. Mayo and Mayo Clinic are registered trademarks owned by Mayo Foundation for Medical Education and Research. Two Mid America Plaza, Suite 110, Oakbrook Terrace, IL 60181. King-Devick Test is for screening purposes only and any suspicion or indication of head trauma should be evaluated by a licensed professional.