Dr. Greenhaw attended The University of Oklahoma in Norman, OK where he graduated with a Bachelor of Science degree in zoology in 2003. He then received his doctorate at Northeastern State University College of Optometry (NSUCO) in Tahlequah, Oklahoma where he gained specialized knowledge in advanced clinical methods and ocular laser procedures. As well as completing his externship at McCormick Vision Center in Austin, Texas, he participated in many clinical rotations at NSUCO, W. W. Hastings Hospital in Tahlequah, Park View School for the Blind and clinics in Salina, Stilwell, Jay and Sallisaw.

Dr. Greenhaw is certified to perform specific laser procedures and orthokeratology, a non-surgical correction of nearsightedness. Dr. Greenhaw has received several awards in recognition of his outstanding eye care from NSUCO and he is also actively involved in several professional optometric organizations including American Optometric Association and Oklahoma Association of Optometric Physicians.