Costenbader and Marshall M. Parks (his mentee who would later be known to many as "the father of pediatric ophthalmology") began the first ophthalmology fellowship trained program of any subspecialty at the Children's Hospital in Washington, D.C., now known as the Children's National Medical Center.
Costenbader i Marshall M.Parks (njegov protégé će kasnije postati poznat kao ″otac pedijatrijske oftalmologije″) počeli su prve programe obuke za subspecijalizaciju u Dječjoj bolnici u Washingtonu, D.C., koja je sada poznata kao Dječji nacionalni medicinski centar (Children′s National Medical Center).