1. Best candidates will have completed an optional ocular disease residency: http://www.opted.org/about-optometric-education/residency-programs/ would be a good place to start. This site has contact info all the optometry schools.
2. Your state's Optometric Association will have a database of OD's looking to relocate to your state.
3. A letter to the OD's who currently refer to you might come up with some good leads as well.
Thanks. If I recall correctly, weren't you advertising to hire someone a while back? Did you find someone? Interested to know how that turned out, it sounded like you had a good opportunity to offer someone.