Coming from the perspective of someone that interviews several ODs per year for the past 12 or more years, I think residency is nice if you have it but not required.
I believe that most ODs coming out of school will have a basic understanding of eye disease. I look for their 4th year experience with some good medical training on externships. I also look at what they did with their summers. Were they playing or working in the field at a doctors office? There is a huge experience factor that can be helpful with the more patient touches you can have.
I also look for someone who can build relationships. A doctor may be really smart and can detect any type of eye disease, but I have seen lots of those smart doctors fail in business because they do not connect with people. I can think of one doctor who is absolutely brilliant in the clinic. He bought out a retiring doctor's practice that had a very good chair-side manner and had built his practice through relationships over the years.
Within two years, the practice was in the hole and the new doctor claimed bankruptcy.