Graduated from the University of Oklahoma Medical School in 1966. Completed his internship at Maricopa County General Hospital in Phoenix, Az. Dr. Astle served in the U. S. Army Medical Corps in Vietnam from from 1967 to 1969. Dr. Astle's Residency was completed in 1973 at the University of Colorado Medical School. He is Board Certified by the American Board of Ophthalmology and a member of the American Academy of Ophthalmology, and the American Medical Association.